Lochinvar Wall Mount Boiler Wh 55 399 Users Manual I O Rev H

WH 55-399 to the manual 08959e06-5362-414a-a7e2-1244aa81bc5f

2015-02-09

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WH-I-O Rev H

Installation & Operation Manual
Models: WH 55 - 399

 WARNING

This manual must only be used by
a qualified heating installer / service
technician. Read all instructions,
including this manual and the Knight
Wall Mount Service Manual, before
installing. Perform steps in the order
given. Failure to comply could result
in severe personal injury, death, or
substantial property damage.

Save this manual for future reference.

Contents
HAZARD DEFINITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . 2
PLEASE READ BEFORE PROCEEDING . . . . . . . . . . . . 3
THE KNIGHT WALL MOUNT BOILER-- HOW IT WORKS . 4-5
RATINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1. DETERMINE BOILER LOCATION
Provide Clearances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Provide Air Openings to Room . . . . . . . . . . . . . . . . . . . . . 9
Wall Mounting Location . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Residential Garage Installation . . . . . . . . . . . . . . . . . . . . . 9
Vent and Air Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Prevent Combustion Air Contamination . . . . . . . . . . . . . . . 9
Corrosive Contaminants and Sources . . . . . . . . . . . . . . . 10
Using an Existing Vent System to Install a New Boiler . . 10
Removing a Boiler from Existing Common Vent . . . . . . . 11
2. PREPARE BOILER
Remove Boiler from Wood Pallet . . . . . . . . . . . . . . . . . . . 12
Gas Conversions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Mounting the Boiler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3. GENERAL VENTING
Direct Venting Options ..................................................... 14
Install Vent and Combustion Air Piping ........................... 15
Requirements for Installation in Canada .......................... 16
Sizing ............................................................................... 16
Materials ............................................................................ 17
Optional Room Air ............................................................ 18
PVC/CPVC ....................................................................... 19
Polypropylene................................................................... 20
Stainless Steel Vent ......................................................... 21
4. SIDEWALL DIRECT VENTING
Vent/Air Termination - Sidewall ................................... 22-28
Determine Location................................................ 22-24
Prepare Wall Penetrations .......................................... 24
Multiple Vent/Air Terminations ......................................... 25
Sidewall Termination - Optional Concentric Vent ....... 26-28
5. VERTICAL DIRECT VENTING
Vent/Air Termination - Vertical .................................... 29-30
Determine Location..................................................... 29
Prepare Roof Penetrations ......................................... 29
Multiple Vent/Air Terminations .................................... 30
Vertical Termination - Optional Concentric Vent ... 30-31
Alternate Vertical Concentric Venting ......................... 32

6. HYDRONIC PIPING
System Water Piping Methods . . . . . . . . . . . . . . . . . . . . . 33
Low Water Cutoff Device . . . . . . . . . . . . . . . . . . . . . . . . . 33
Chilled Water System. . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Freeze Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
General Piping Information . . . . . . . . . . . . . . . . . . . . . . . 33
Near Boiler Piping Components . . . . . . . . . . . . . . . . . . . . 34
Near Boiler Piping Connections . . . . . . . . . . . . . . . . . . . . 35
Circulator Sizing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Variable Speed Pump Option . . . . . . . . . . . . . . . . . . . . . 37
7. GAS CONNECTIONS
Connecting Gas Supply Piping . . . . . . . . . . . . . . . . . . . . 48
Natural Gas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Pipe Sizing for Natural Gas . . . . . . . . . . . . . . . . . . . . 49
Natural Gas Supply Pressure Requirements . . . . . . . 49
Propane Gas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Pipe Sizing for Propane Gas . . . . . . . . . . . . . . . . . . . 49
Propane Supply Pressure Requirements . . . . . . . . . . 49
Check Inlet Gas Supply . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Gas Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Gas Valve Replacement . . . . . . . . . . . . . . . . . . . . . . . . . 51
8. FIELD WIRING
Line Voltage Connections . . . . . . . . . . . . . . . . . . . . . . . . 52
Low Voltage Connections . . . . . . . . . . . . . . . . . . . . . . . . 52
Wiring of the Cascade . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
9. CONDENSATE DISPOSAL
Condensate Drain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
10. STARTUP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57-63
11. OPERATING INFORMATION
General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Cascade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Sequence of Operation . . . . . . . . . . . . . . . . . . . . . . . 68-69
Knight Wall Mount Boiler Control Module . . . . . . . . . . . . 70
Status Display Screens . . . . . . . . . . . . . . . . . . . . . . . 71-73
12. MAINTENANCE
Maintenance and Annual Startup . . . . . . . . . . . . . . . . 74-77
13. DIAGRAMS
Ladder Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Wiring Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Revision Notes . . . . . . . . . . . . . . . . . . . . . . . . . Back Cover

Hazard definitions
The following defined terms are used throughout this manual to bring attention to the presence of hazards of various risk levels or
to important information concerning the life of the product.
DANGER indicates an imminently hazardous situation which, if not avoided, will result in death or serious
 DANGER injury.
WARNING indicates a potentially hazardous situation which, if not avoided, could result in death or serious

 WARNING injury.

CAUTION indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate

 CAUTION injury.
CAUTION

CAUTION used without the safety alert symbol indicates a potentially hazardous situation which, if not
avoided, may result in property damage.

NOTICE

NOTICE indicates special instructions on installation, operation, or maintenance that are important but not
related to personal injury or property damage.

Installation & Operation Manual

Please read before proceeding
 WARNING

Installer – Read all instructions,
including this manual and the Knight
Wall Mount Service Manual, before
installing. Perform steps in the order
given.
User – This manual is for use only
by a qualified heating installer/
service technician. Refer to the User’s
Information Manual for your reference.
Have this boiler serviced/inspected by
a qualified service technician, at least
annually.
Failure to comply with the above could
result in severe personal injury, death or
substantial property damage.

NOTICE

When calling or writing about the boiler
– Please have the boiler model and serial
number from the boiler rating plate.
Consider piping and installation when
determining boiler location.
Any claims for damage or shortage in
shipment must be filed immediately
against the transportation company by
the consignee.
Factory warranty (shipped with unit)
does not apply to units improperly
installed or improperly operated.

 WARNING

Failure to adhere to the guidelines on this
page can result in severe personal injury,
death, or substantial property damage.

 WARNING

If the information in this manual is not
followed exactly, a fire or explosion may
result causing property damage, personal
injury or loss of life.

When servicing boiler –
• To avoid electric shock, disconnect electrical supply
before performing maintenance.
• To avoid severe burns, allow boiler to cool before
performing maintenance.

Boiler operation –
• Do not block flow of combustion or ventilation air to
the boiler.
• Should overheating occur or gas supply fail to shut off,
do not turn off or disconnect electrical supply to
circulator. Instead, shut off the gas supply at a location
external to the appliance.
• Do not use this boiler if any part has been under water.
The possible damage to a flooded appliance can be
extensive and present numerous safety hazards. Any
appliance that has been under water must be replaced.

Boiler water –
• Thoroughly flush the system (without boiler
connected) to remove sediment. The high-efficiency
heat exchanger can be damaged by build-up or
corrosion due to sediment.
• Continual fresh make-up water will reduce boiler life.
Mineral buildup in the heat exchanger reduces heat
transfer, overheats the stainless steel heat exchanger,
and causes failure. Addition of oxygen carried in by
makeup water can cause internal corrosion in system
components. Leaks in boiler or piping must be repaired
at once to prevent makeup water.
 CAUTION

This appliance MUST NOT be installed
in any location where gasoline or
flammable vapors are likely to be present.
WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electric switch; do
not use any phone in your building.
• Immediately call your gas supplier
from a near by phone. Follow the
gas supplier’s instructions.
• If you cannot reach your gas supplier,
call the fire department.
• Installation and service must be
performed by a qualified installer,
service agency, or the gas supplier.

 CAUTION

Do not use petroleum-based cleaning or
sealing compounds in the boiler system.
Gaskets and seals in the system may be
damaged. This can result in substantial
property damage.
Do not use “homemade cures” or “boiler
patent medicines”. Serious damage to
the boiler, personnel, and/or property
may result.

Freeze protection fluids –
• NEVER use automotive antifreeze. Use only inhibited
propylene glycol solutions, which are specifically
formulated for hydronic systems. Ethylene glycol is
toxic and can attack gaskets and seals used in hydronic
systems.

Installation & Operation Manual

The Knight Wall Mount Boiler - How it works...
1.

Stainless steel heat exchanger
Allows system water to flow around specially designed
tubes for maximum heat transfer, while providing
protection against flue gas corrosion.

Combustion chamber access cover
Allows access to the combustion side of the heat
exchanger.

Blower

18. High voltage junction box

Venturi
Flue gas sensor (limit rated)

Allows for the connection of the PVC air intake pipe to
the boiler.
The junction box contains the connection points for the line
voltage power and all pumps.

19. Low voltage connection board
The connection board is used to connect external low voltage
devices.

20. Low voltage wiring connections (knockouts)
Conduit connection
connection board.

22. Access door
23. Ignition electrode

Temperature and pressure gauge (field installed, not
shown)
Monitors the outlet temperature of the boiler as well as the
system water pressure.

10. Electronic LCD display
The electronic display consists of 4 buttons, a navigation dial
and a multiple line liquid crystal display.

11. Flue pipe adapter
Allows for the connection of the PVC vent pipe system to the
boiler.

12. Burner (not shown)
Made with metal fiber and stainless steel construction,
the burner uses pre-mixed air and gas and provides a
wide range of firing rates.

13. Water outlet (system supply)
The water outlet is the water connection for water leaving the
boiler and entering the system.

14. Water inlet (system return)
The water inlet is the water connection for water entering the
boiler from the system.

for

the

low

voltage

Connects the condensate drain line.

This sensor monitors boiler outlet water temperature (system
supply). If selected as the controlling sensor, the control
module adjusts boiler firing rate so the outlet temperature is
correct.

Boiler inlet temperature sensor

points

21. Condensate drain connection

Boiler outlet temperature sensor (housed with high
limit sensor)

This sensor monitors return water temperature (system
return). If selected as the controlling sensor, the control
module adjusts the boiler firing rate so the inlet temperature is
correct.

The SMART SYSTEM Control responds to internal and
external signals and controls the blower, gas valve, and pumps
to meet the heating demand.

Gas valve

This sensor monitors the flue gas exit temperature. The control
module will modulate and shut down the boiler if flue gas
temperature gets too hot. This protects the flue pipe from
overheating.

16. SMART SYSTEM Control Module

17. Air intake adapter

The venturi controls air and gas flow into the burner.

Threaded pipe connection.
This pipe should be
connected to the incoming gas supply for the purpose of
delivering gas to the boiler.

The blower pulls in air and gas through the venturi (item
5). Air and gas mix inside the blower and are pushed into the
burner, where they burn inside the combustion chamber.
The gas valve senses the negative pressure created by the
blower, allowing gas to flow only if the gas valve is
powered and combustion air is flowing.

15. Gas connection pipe

Provides access to all internal components.
Provides direct spark for igniting the burner.

24. Flame inspection window
The quartz glass window provides a view of the burner
surface and flame.

25. Gas shutoff switch
An electrical switch designed to cut power to the gas valve to
prevent releasing any gas.

26. High limit sensor (housed with outlet sensor)
Device that monitors the outlet water temperature. If the
temperature exceeds its setting, it will break the control circuit,
shutting the boiler down.

27. Relief valve
Protects the heat exchanger from an over pressure condition.
The relief valve provided with the unit is set at 30 psi.

28. Flame sensor
Used by the control module to detect the presence of burner
flame.

29. Line voltage wiring connections (knockouts)
Conduit connection points for the high voltage junction box.

30. Transformer
The transformer provides 24V power to the integrated control.

31. ModBus
The optional ModBus option provides intelligent building
system communications.

32. On/Off switch
The On/Off switch is used to turn 120 VAC on and off to the
unit.

33. Manual air vent

Allows for removal of trapped air from the heat exchanger.

Installation & Operation Manual

The Knight Wall Mount Boiler - How it works...

(continued)

Models 55 - 399

11
21
15

29
32

FRONT OF UNIT

IMG00117

Front View

Bottom View

17
27

5
25

4
11

24
19

7
26

IMG00162

Left Side (inside unit)

IMG00161

Right Side (inside unit)

Installation & Operation Manual

Ratings
A

S
M

Knight Wall Mount Boiler
AHRI Rating
Input
MBH

Model Number
Note: Change
“N” to “L” for
L.P. gas models.

Heating
Capacity
MBH

Net
AHRI
Ratings
Water,
MBH

(Note 5)

Other Specifications
AFUE
%

Boiler Water
Water
Gas
Content
Connections Connections
Gallons

Vent/Air
Size

(Note 4)

Min

Max

(Note 2, 8)

(Note 3, 8)

(Note 1, 8)

WHN055

2.5

1/2"

WHN085

2.5

1/2"

WHN110

110

102

3.5

1/2"

WHN155

155

144

125

3.5

1/2"

WHN199

199

186

162

5.0

1 1/4"

1/2"

WHN285

285

265

230

5.0

1 1/4"

1/2"

WHN399

399

379

330

6.5

1 1/2"

3/4"

Maximum allowed working pressure is located on the rating plate.
7. The Knight Wall Mount boiler input rate, on some models,
Notes:
is reduced for vent lengths beyond the minimum. Two inch
1. As an Energy Star Partner, Lochinvar has determined that
vent will reduce Models WH(N,L) 055, WH(N,L) 085 and
Knight wall mount boilers meet the Energy Star guidelines
WH(N,L)110 by 0.6%, 0.94%, and 1.2% for every 10 feet
for energy efficiency.
of vent. Three inch vent will reduce Models WH(N,L)155,
2. The ratings are based on standard test procedures prescribed
WH(N,L)199 and WH(N,L) 285 by 0.3%, 0.5%, and 0.6%
by the United States Department of Energy.
for every 10 feet of vent. Four inch vent will reduce Model
WH(N,L) 399 by 0.4% for every 10 feet of vent.
3. Net AHRI ratings are based on net installed radiation of
8. Ratings have been confirmed by the Hydronics Section of
sufficient quantity for the requirements of the building
AHRI. Model 399 has a thermal efficiency rating.
and nothing need be added for normal piping and pickup.
Ratings are based on a piping and pickup allowance of 1.15.
9. Knight wall mount boilers comply with the requirements
of CSD-1 Section CW-400 requirements as a temperature
4. Knight wall mount boilers require special gas venting. Use
operation control. The manual reset high limit provided
only the vent materials and methods specified in the Knight
with the Knight wall mount boiler is listed to UL353.
Wall Mount Installation and Operation Manual.
5. Standard Knight wall mount boilers are equipped to operate
from sea level to 4,500 feet only with no adjustments. The
boiler will de-rate by 4% for each 1,000 feet above sea level
up to 4,500 feet.
6. High altitude Knight wall mount boilers are equipped
HIGH ALTITUDE
to operate from 3,000 to 12,000 feet only with no field
adjustments. The boiler will de-rate by 2% for each 1,000
feet above 3,000 feet. High altitude models are manufactured
with a different control module for altitude operation, but
the operation given in this manual remains the same as the
standard boilers. A high altitude label (as shown in FIG. A)
is also affixed to the unit.
NOTICE

UNIT EQUIPPED FOR

3,000FT TO 12,000FT

Figure A High Altitude Label Location

Installation & Operation Manual

Determine boiler location

Installation must comply with:

 WARNING

This appliance is certified as an indoor
appliance. Do not install the appliance
outdoors or locate where the appliance will
be exposed to freezing temperatures or to
temperatures that exceed 100°F.
Do not install the appliance where the
relative humidity may exceed 93%. Do not
install the appliance where condensation
may form on the inside or outside of the
appliance, or where condensation may fall
onto the appliance.
Failure to install the appliance indoors
could result in severe personal injury,
death, or substantial property damage.

 WARNING

This appliance requires a special venting
system. The vent connection to the
appliance is made of CPVC. Field supplied
vent fittings must be cemented to the CPVC
fitting on the boiler. Use only the vent
materials, primer, and cement specified in
the manual to make the vent connections.
Failure to follow this warning could result
in fire, personal injury, or death.

• Local, state, provincial, and national codes, laws,
regulations, and ordinances.
• National Fuel Gas Code, ANSI Z223.1 – latest edition.
• Standard for Controls and Safety Devices for Automatically
Fired Boilers, ANSI/ASME CSD-1, when required.
• National Electrical Code.
• For Canada only: B149.1 Installation Code, CSA C22.1
Canadian Electrical Code Part 1 and any local codes.
NOTICE

The Knight wall mount boiler gas
manifold and controls met safe lighting
and other performance criteria when the
boiler underwent tests specified in ANSI
Z21.13 – latest edition.

Before locating the boiler, check:
1.

Check for nearby connection to:
• System water piping
• Venting connections
• Gas supply piping
• Electrical power

Locate the appliance so that if water connections should
leak, water damage will not occur. When such locations
cannot be avoided, it is recommended that a suitable
drain pan, adequately drained, be installed under the
appliance. The pan must not restrict combustion air
flow. Under no circumstances is the manufacturer to be
held responsible for water damage in connection with
this appliance, or any of its components.

Check area around the boiler. Remove any combustible
materials, gasoline and other flammable liquids.

Failure to keep boiler area clear and free
 WARNING of combustible materials, gasoline, and
other flammable liquids and vapors can
result in severe personal injury, death, or
substantial property damage.
4. The Knight wall mount boiler must be installed so
that gas control system components are protected from
dripping or spraying water or rain during operation or
service.
5. If a new boiler will replace an existing boiler, check for
and correct system problems, such as:
• System leaks causing oxygen corrosion or heat exchanger
cracks from hard water deposits.
• Incorrectly-sized expansion tank.
• Lack of freeze protection in boiler water causing system
and boiler to freeze and leak.

Closet and alcove installations
A closet is any room the boiler is installed in which the room
volume is less than the room volume listed in the table below.
An alcove is any room which meets the criteria for a closet,
but it does not have a door.

Model

Room Volume
(in cubic feet)

55 - 85

110 - 285

108

399

178

Example: Room dimensions = 4 feet long, 4 feet wide, and
9 foot ceiling = 4 x 4 x 9 = 144 cubic feet. This would be
considered a closet for the WHN399 model.
For closet and alcove installations as shown
 WARNING
in FIG.’s 1-1 and 1-2, CPVC or stainless
steel vent material must be used inside
the structure. The two ventilating air
openings shown in FIG. 1-1 are required
for this arrangement. Failure to follow
this warning could result in fire, personal
injury, or death.

Provide clearances:
Clearances from combustible materials
1. Hot water pipes—at least 1/4" from combustible materials.
2. Vent pipe – at least 1" from combustible materials.
3. See FIG.’s 1-1 and 1-2 on page 8 for other clearance
minimums.
Clearances for service access
1. See FIG.’s 1-1 and 1-2 on page 8 for recommended
service clearances. If you do not provide the minimum
clearances shown, it may not be possible to service the
boiler without removing it from the space.

Installation & Operation Manual

Determine boiler location

Figure 1-1 Closet Installation - Minimum Required Clearances
 WARNING

TOP
6" MINIMUM

LEFT
0" MINIMUM

VENTILATING
AIR OPENING

For closet installations, CPVC,
polypropylene or stainless steel
vent material MUST BE used in
a closet structure due to elevated
temperatures. Failure to follow
this warning could result in fire,
personal injury, or death.

RIGHT
0" MINIMUM
1" MINIMUM CLEARANCE
AROUND VENT PIPE
CLOSED DOOR

VENTILATING
AIR OPENING

FRONT
BOTTOM
0" MINIMUM

*AREA OF EACH OPENING:

6" MINIMUM

1 SQ. INCH PER 1000 BTU PER HOUR INPUT
WITH A MINIMUM OF 100 SQ. INCHES.

1/4" MINIMUM CLEARANCE
AROUND HOT WATER PIPES

RECOMMENDED SERVICE CLEARANCES:
FRONT:
24”
BOTTOM: 24”
LEFT SIDE: 12”

Note: Service clearances are recommendations only.

Figure 1-2 Alcove Installation - Minimum Required Clearances
TOP
6" MINIMUM

LEFT
0" MINIMUM

 WARNING

RIGHT
0" MINIMUM
1" MINIMUM CLEARANCE
AROUND VENT PIPE

For alcove installations, CPVC,
polypropylene or stainless steel
vent material MUST BE used in
an alcove structure due to elevated
temperatures. Failure to follow
this warning could result in fire,
personal injury, or death.

OPEN FRONT

FRONT
6" MINIMUM

BOTTOM
0" MINIMUM

1/4" MINIMUM CLEARANCE
AROUND HOT WATER PIPES

RECOMMENDED SERVICE CLEARANCES:
FRONT:
24”
BOTTOM: 24”
LEFT SIDE: 12”

Note: Service clearances are recommendations only.

Installation & Operation Manual

Determine boiler location

(continued)

Provide air openings to room:

Residential garage installation

Knight wall mount boiler alone in boiler room

Precautions

1. No air ventilation openings into the boiler room are
needed when clearances around the Knight wall mount
boiler are at least equal to the SERVICE clearances
shown in FIG.’s 1-1 and 1-2. For spaces that do NOT
supply this clearance, provide two openings as shown
in FIG. 1-1. Each opening must provide one square
inch free area per 1,000 Btu/hr of boiler input.

Take the following precautions when installing the appliance in
a residential garage. If the appliance is located in a residential
garage, it should be installed in compliance with the latest
edition of the National Fuel Gas Code, ANSI Z223.1 and/or
CAN/CGA-B149 Installation Code.

Knight wall mount boiler in same space with other
gas or oil-fired appliances
1. Follow the National Fuel Gas Code (U.S.) or CSA
B149.1 (Canada) to size/verify size of the combustion/
ventilation air openings into the space.
The space must be provided with
 WARNING
combustion/ventilation air openings
correctly sized for all other appliances
located in the same space as the Knight
wall mount boiler.
Do not install the boiler in an attic.
Failure to comply with the above
warnings could result in severe personal
injury, death, or substantial property
damage.
2. Size openings only on the basis of the other appliances
in the space. No additional air opening free area is
needed for the Knight wall mount boiler because it
takes its combustion air from outside (direct vent
installation).

Wall mounting location
Ensure the wall for which the boiler is intended to be
mounted is comprised of either, cement, brick, block, or
wooden studs spaced 16" apart from center. Ensure the
wall is capable of supporting at least 250 pounds for Models
55 - 285 and 300 pounds for the 399 Models.
If flooding is possible, elevate the boiler sufficiently to
prevent water from reaching the boiler.
Ensure the boiler is installed in a location that minimizes
the risk of water damage due to valves, pumps, etc.

• Appliances located in residential garages and in
adjacent spaces that open to the garage and are not part
of the living space of a dwelling shall be installed so that
all burners and burner ignition devices are located not
less than 18 inches (46 cm) above the floor.
• The appliance shall be located or protected so that it is
not subject to physical damage by a moving vehicle.

Vent and air piping
The Knight wall mount boiler requires a special vent system,
designed for pressurized venting.
The boiler is to be used for either direct vent installation or for
installation using indoor combustion air. When room air is
considered, see Section 3, General Venting. Note prevention of
combustion air contamination below when considering vent/
air termination.
Vent and air must terminate near one another and may be
vented vertically through the roof or out a side wall, unless
otherwise specified. You may use any of the vent/air piping
methods covered in this manual. Do not attempt to install the
Knight wall mount boiler using any other means.
Be sure to locate the boiler such that the vent and air piping can
be routed through the building and properly terminated. The
vent/air piping lengths, routing and termination method must
all comply with the methods and limits given in this manual.

Prevent combustion air contamination
Install air inlet piping for the Knight wall mount boiler as
described in this manual. Do not terminate vent/air in locations
that can allow contamination of combustion air. Refer to
Table 1A, page 10 for products and areas which may cause
contaminated combustion air.
 WARNING

You must pipe combustion air to the boiler
air intake. Ensure that the combustion air will
not contain any of the contaminants in Table
1A, page 10. Contaminated combustion air
will damage the boiler, resulting in possible
severe personal injury, death or substantial
property damage. Do not pipe combustion
air near a swimming pool, for example. Also,
avoid areas subject to exhaust fumes from
laundry facilities. These areas will always
contain contaminants.

Installation & Operation Manual

Determine boiler location

Table 1A Corrosive Contaminants and Sources
Products to avoid:
Spray cans containing chloro/fluorocarbons
Permanent wave solutions
Chlorinated waxes/cleaners
Chlorine-based swimming pool chemicals
Calcium chloride used for thawing
Sodium chloride used for water softening
Refrigerant leaks
Paint or varnish removers
Hydrochloric acid/muriatic acid
Cements and glues
Antistatic fabric softeners used in clothes dryers
Chlorine-type bleaches, detergents, and cleaning solvents
found in household laundry rooms
Adhesives used to fasten building products and other
similar products
Areas likely to have contaminants
Dry cleaning/laundry areas and establishments
Swimming pools
Metal fabrication plants
Beauty shops
Refrigeration repair shops
Photo processing plants
Auto body shops
Plastic manufacturing plants
Furniture refinishing areas and establishments
New building construction
Remodeling areas
Garages with workshops

When using an existing vent system to
install a new boiler:
 WARNING

Failure to follow all instructions can result
in flue gas spillage and carbon monoxide
emissions, causing severe personal injury
or death.

Check the following venting components before installing:
• Material - For materials listed for use with this appliance,
see Section 3 - General Venting. For polypropylene or
stainless steel venting, an adapter of the same
manufacturer must be used at the flue collar connection.
• Size - To ensure proper pipe size is in place, see Table 3A.
Check to see that this size is used throughout the vent
system.
• Manufacturer - For a stainless steel or polypropylene
application, you must use only the listed manufacturers
and their type product listed in Tables 3E and 3G for CAT
IV positive pressure venting with flue producing
condensate.
• Supports - Non-combustible supports must be in place
allowing a minimum 1/4" rise per foot. The supports
should adequately prevent sagging and vertical slippage,
by distributing the vent system weight. For additional
information, consult the vent manufacturer’s
instructions for installation.
• Terminations - Carefully review Sections 3 through 5 to
ensure requirements for the location of the vent and air
terminations are met and orientation of these fit the
appropriate image from the Sidewall or Vertical
options listed in the General Venting Section. For
stainless steel vent, only use terminations listed in Table
3H for the manufacturer of the installed vent.
• Seal - With prior requirements met, the system should be
tested to the procedure listed in parts (c) through (f) of
the Removal of an Existing Boiler Section on page 11.
With polypropylene and stainless steel vent, seal and connect
all pipe and components as specified by the vent manufacturer
used; with PVC/CPVC vent, see the Installing Vent or Air
Piping Section on page 19.
If any of these conditions are not met,
 WARNING the existing system must be updated or
replaced for that concern. Failure to
follow all instructions can result in flue gas
spillage and carbon monoxide emissions,
causing severe personal injury or death.

Installation & Operation Manual

Determine boiler location

(continued)

When removing a boiler from existing
common vent system:
 DANGER

Do not install the Knight wall mount
boiler into a common vent with any other
appliance. This will cause flue gas spillage or
appliance malfunction, resulting in possible
severe personal injury, death, or substantial
property damage.

 WARNING

Failure to follow all instructions can result
in flue gas spillage and carbon monoxide
emissions, causing severe personal injury or
death.

g. Any improper operation of the common venting system
should be corrected so the installation conforms with
the National Fuel Gas Code, ANSI Z223.1/NFPA 54
and/or CAN/CSA B149.1, Natural Gas and Propane
Installation Code. When resizing any portion of the
common venting system, the common venting system
should be resized to approach the minimum size as
determined using the appropriate tables in Part 11 of
the National Fuel Gas Code, ANSI Z223.1/NFPA and/or
CAN/CSA B149.1, Natural Gas and Propane Installation
Code.

At the time of removal of an existing boiler, the following steps
shall be followed with each appliance remaining connected
to the common venting system placed in operation, while the
other appliances remaining connected to the common venting
system are not in operation.
a. Seal any unused openings in the common venting system.
b. Visually inspect the venting system for proper size and
horizontal pitch and determine there is no blockage or
restriction, leakage, corrosion, or other deficiencies, which
could cause an unsafe condition.
c.

Test vent system – Insofar as is practical, close all building
doors and windows and all doors between the space in
which the appliances remaining connected to the common
venting system are located and other spaces of the building.
Turn on clothes dryers and any appliance not connected to
the common venting system. Turn on any exhaust fans,
such as range hoods and bathroom exhausts, so they will
operate at maximum speed. Do not operate a summer
exhaust fan. Close fireplace dampers.

d. Place in operation the appliance being inspected. Follow
the lighting instructions. Adjust thermostat so appliance
will operate continuously.
e.

Test for spillage at the draft hood relief opening after
5 minutes of main burner operation. Use the flame of a
match or candle, or smoke from a cigarette, cigar, or pipe.

After it has been determined that each appliance remaining
connected to the common venting system properly vents
when tested as outlined herein, return doors, windows,
exhaust fans, fireplace dampers, and any other gas-burning
appliance to their previous conditions of use.

Installation & Operation Manual

Prepare boiler

Remove boiler from wood pallet

Table 2A LP Conversion Table
LP Conversion Table
Model
LP Orifice Stamping
55
055
85
085
110
110
155
155
199
199
285
H285
399
8.0

1. After removing the outer shipping carton from the boiler,
remove the parts box.
2. To remove the boiler from the pallet:
a. Remove the two (2) lag bolts securing the bottom
of the unit to the pallet.
b. Lift the boiler off the wall bracket mounted to
the pallet.
3. Remove the two (2) lag bolts securing the wall bracket to
the wood pallet. Be certain not to lose the wall bracket
as it will be needed for securing the boiler to the wall
(FIG. 2-1).
NOTICE

Do not drop the boiler or bump the jacket
on the floor or pallet. Damage to the
boiler can result.

Figure 2-1 Boiler Mounted on Shipping Pallet

Remove the front access cover from the unit (no tools
required for removal).

Models 55 - 285 only, locate the power switch on the gas
valve and turn the power switch to the “OFF” position
(FIG. 2-2).

Model 399 only, shut off power at the source.

4. Disconnect the Molex plug from the gas valve.
5. Using a 5/16" nut driver, loosen the band clamp securing the
air intake coupler to the gas valve venturi. Remove the air
intake pipe and coupler from the gas valve venturi.

REMOVE SHIPPING
[WALL] BRACKET
DO NOT DISCARDWILL BE NEEDED TO
SECURE THE BOILER
TO THE WALL

6. Using an Allen wrench, remove the screws securing the
gas valve venturi to the inlet of the combustion blower
(FIG. 2-2).
Figure 2-2 Gas Valve Power Switch & Venturi Removal
REMOVE THE SCREWS SECURING
THE GAS VALVE VENTURI TO THE
INLET OF THE COMBUSTION
BLOWER

Gas conversions
 WARNING

The gas conversion procedure should
be accomplished BEFORE the boiler is
installed. For a boiler already installed,
you must turn off gas supply, turn off
power, and allow the boiler to cool before
proceeding. You must also completely
test the boiler after conversion to verify
performance as described under Start-up,
Section 10 of this manual.
You must install the propane orifice to fire
the Knight wall mount boiler on propane.
Verify when installing that the orifice size
marking matches boiler size (Table 2A).
Failure to comply could result in severe
personal injury, death, or substantial
property damage.

7. Using an Allen wrench, remove the screws securing the gas
pipe to the gas valve. Remove the gas valve venturi assembly
from the unit (FIG. 2-3).
8. Using an Allen wrench, remove the venturi from the gas
valve.
9. Locate the propane orifice disk from the conversion kit bag.
Verify that the stamping on the orifice disk matches the
boiler size (see Table 2A).
10. Place the orifice into the black rubber grommet in the side of
the gas valve and secure inside the gas valve (see FIG. 2-3).
11. Reattach the venturi to the gas valve and reposition the gas
valve venturi assembly inside the unit. Secure the venturi
back to the gas valve (FIG. 2-3).
12. Reattach the gas pipe to the gas valve. Reattach the air intake
and coupler and tighten down on the band clamp.

Installation & Operation Manual

Prepare boiler

(continued)

13. Reattach the Molex plug to the gas valve.
14. Models 55 - 285 only, turn the gas valve power switch to
the “ON” position.
15. Model 399 only, turn on power at the source.
16. After the installation is complete, fill out the gas conversion
label (in the conversion kit bag) and affix it to the unit
under the boiler rating plate inside the unit. Attach the
LP caution label (in the conversion kit bag) to the left side
of the unit in the lower left corner.

 WARNING The boiler is too heavy for a single person to
lift. A minimum of two people is needed for
mounting the boiler onto the bracket.
Mounting to a concrete wall:
1.

Mount the wall bracket using the two (2) wedge anchor
bolts provided with the bracket. To mount the wedge
anchor bolts, drill a 1/4" diameter hole 1 1/8" deep and
insert anchor. Hang the bracket from the anchor and secure
with the two nuts provided. Make sure the top edge of the
bracket is away from the wall. Ensure bracket is level when
mounted. Extreme care is needed to ensure the bolts are
secured in the center of the studs.

17. Replace the front access cover.
 WARNING

After converting to LP, check combustion
per the Start-up procedure in Section 10
of this manual. Failure to check and
verify combustion could result in severe
personal injury, death, or substantial
property damage.

Note: If wall thickness does not allow a 1 1/8" deep hole,
field supplied hardware suitable for the application should be
provided.
2.

Figure 2-3 Installing Propane Orifice
GAS VALVE

GROMMET
BRASS ORIFICE

Hang the boiler on the bracket and secure the bottom of the
boiler with two (2) remaining anchors, following the
instructions above.
The boiler is too heavy for a single person to
 WARNING lift. A minimum of two people is needed for
mounting the boiler onto the bracket.

Mounting to a metal studded wall:
1.

The wall mount bracket is designed for a stud spacing of
16 inches from center. For other stud spacing a solid
mounting surface must be provided by the installer.
Do not mount the boiler to a hollow wall. Be
sure to mount the boiler to the studs only.
Mount the wall bracket using two (2) field supplied toggle
bolts capable of supporting 100 pounds each. Ensure the
top edge of the bracket is away from the wall. Ensure the
bracket is level when mounted. Extreme care is needed to
ensure the bolts are secured in the center of the studs.

 WARNING

SCREWS

VENTURI

Mounting the boiler
See page 9 of this manual for boiler mounting location
instructions.
The Knight Wall Mount boiler is not
NOTICE
intended for floor installation.

Hang the boiler on the bracket and secure the bottom of the
boiler with two (2) field supplied toggle bolts.
 WARNING The boiler is too heavy for a single person
to lift. A minimum of two people is needed
for mounting the boiler onto the bracket.

Mounting to a wood studded wall:
Figure 2-4 Mounting the Boiler
1.

The wall mount bracket is designed for a stud spacing of
16 inches from center. For other stud spacing a solid
mounting surface must be provided by the installer.

WALL:
WOOD OR METAL STUDS ON
16" CENTERS -ORMASONRY / POURED CONCRETE
MOUNTING BRACKET
(FACTORY SUPPLIED)

 WARNING Do not mount the boiler to a hollow wall.
Be sure to mount the boiler to the studs
only.
2.

Mount the wall bracket using the 2 1/4" lag bolts
provided. Make sure the top edge of the bracket is away
from the wall. Ensure the bracket is level when mounted.
Extreme care is needed to ensure the bolts are secured in
the center of the studs.

Hang the boiler on the bracket and secure the bottom of
the boiler with two (2) additional lag bolts provided.

FASTENERS
APPROPRIATE
FOR WALL TYPE
QTY: 4

Installation & Operation Manual

General venting

Direct venting options - Sidewall Vent

Figure 3-1 Two-Pipe Sidewall Termination - See page
22 for more details

Figure 3-3 Two-Pipe Vertical
Termination - See page 29 for
more details

Figure 3-2 PVC/CPVC Concentric Sidewall
Termination - See page 26 for more details

Figure 3-4 PVC/CPVC Concentric
Vertical Termination - See page 30
for more details

Figure 3-5 Vertical Vent, Sidewall Air
- See page 18 for more details

Installation & Operation Manual

General venting

Install vent and combustion air piping
 DANGER

 WARNING

The Knight wall mount boiler must be
vented and supplied with combustion and
ventilation air as described in this section.
Ensure the vent and air piping and the
combustion air supply comply with these
instructions regarding vent system, air
system, and combustion air quality. See
also Section 1 of this manual.
Inspect finished vent and air piping
thoroughly to ensure all are airtight and
comply with the instructions provided and
with all requirements of applicable codes.
Failure to provide a properly installed vent
and air system will cause severe personal
injury or death.

The Knight wall mount boiler vent and air piping can be
installed through the roof or through a sidewall. Follow the
procedures in this manual for the method chosen. Refer to the
information in this manual to determine acceptable vent and
air piping length.

This appliance requires a special venting
system. Use only approved stainless steel,
PVC, CPVC or polypropylene pipe and
fittings listed in Tables 3D, 3E, and 3G for
vent pipe, and fittings. Failure to comply
could result in severe personal injury,
death, or substantial property damage.

Combustion Air Intake Connector (FIG. 3-6) - Used to
provide combustion air directly to the unit from outdoors.
A fitting is provided on the unit for final connection.
Combustion air piping must be supported per guidelines
listed in the National Mechanical Code, Section 305, Table
305.4 or as local codes dictate.

Vent Connector (FIG.'s 3-7 thru 3-9) - Used to provide a
passageway for conveying combustion gases to the
outside. A transition fitting is provided on the unit for
final connection. Vent piping must be supported per the
National Building Code, Section 305, Table 305.4 or as
local codes dictate.

DO NOT mix components from different
 WARNING systems. The vent system could fail,
causing leakage of flue products into the
living space. Mixing of venting materials
will void the warranty and certification of
the appliance.
NOTICE

Installation must comply with local
requirements and with the National
Fuel Gas Code, ANSI Z223.1 for U.S.
installations or CSA B149.1 for Canadian
installations.

 WARNING

For closet and alcove installations, CPVC,
polypropylene or stainless steel material
MUST BE used in a closet/alcove structure.
Failure to follow this warning could result
in fire, personal injury, or death.

 CAUTION

Improper installation of venting systems
may result in injury or death.

NOTICE

You may use any of the vent/air piping methods covered in
this manual. Do not attempt to install the Knight wall mount
boiler using any other means.
You must also install air piping from outside to the boiler
air intake adapter unless following the Optional Room
Air instructions on page 18 of this manual. The resultant
installation is direct vent (sealed combustion).

Air intake/vent connections

Figure 3-6 Near Boiler Air Piping
AIR

Follow the instructions in Section 1, page
11 of this manual when removing a boiler
from an existing vent system.

 WARNING Do not connect any other appliance to
the vent pipe or multiple boilers to a
common vent pipe. Failure to comply
could result in severe personal injury,
death, or substantial property damage.

Installation & Operation Manual

General venting

Requirements for installation in
Canada

Note: The minimum combustion air and vent piping
length is 12 equivalent feet.

When determining equivalent combustion air and vent
length, add 5 feet for each 90° elbow and 3 feet for each
45° elbow.

Installations must be made with a vent pipe system
certified to ULC-S636.
The first three (3) feet of plastic vent pipe from the
appliance flue outlet must be readily accessible for visual
inspection.
The components of the certified vent system must not be
interchanged with other vent systems or unlisted
pipe/fittings. For concentric vent installations, the inner
vent tube must be replaced with field supplied certified vent
material to comply with this requirement.
The 2" and 3" Concentric Vent Kits available from
Lochinvar (see Section 4 – Sidewall Termination – Optional
Concentric Vent) and the 2" and 3" Concentric Vent Kits
available from IPEX are approved for use on the Knight
wall mount boiler. Both kits are listed to the ULC-S636
standard for use in Canada.

Sizing
The Knight boiler uses model specific combustion air intake and
vent piping sizes as detailed in Table 3A below.
Table 3A Air Intake/Vent Piping Sizes
Model
55

2" Max Vent/
Air
*80 feet

3" Max Vent/ 4" Max Vent/
Air
Air
100 feet
N/A

*50 feet

100 feet

N/A

110

*40 feet

100 feet

N/A

155

N/A

100 feet

N/A

199

N/A

100 feet

N/A

285

N/A

*50 feet

100 feet

399

N/A

100 feet

For Models 55, 85, and 110 using 2"

* WARNING venting and Model 285 using 3" venting,
the first seven (7) equivalent feet of vent
must be CPVC (field supplied). This
includes any transition piece used to
increase or decrease the vent diameter.
NOTICE

Increasing or decreasing combustion air or
vent piping sizes is not authorized.

EXAMPLE: 20 feet of PVC pipe + (4) 90° elbows + (2)
45° elbows + (1) concentric vent kit (CVK3003) = 49
equivalent feet of piping.
NOTICE

The appliance output rating will reduce
by up to 1.5% for each 25 feet of vent
length.

Table 3B Concentric Vent Kit Equivalent Vent Lengths

Model Kit Number

Equivalent Vent
Length

55 - 110

CVK3008

3 feet

155 - 199

CVK3003

3 feet

285 - 399

CVK3007

3 feet

Installation & Operation Manual

General venting

(continued)

Materials
Air inlet pipe materials:
The air inlet pipe(s) must be sealed. Choose acceptable
combustion air inlet pipe materials from the following list:
PVC, CPVC, Polypropylene or ABS
Dryer Vent or Sealed Flexible Duct (not recommended
for rooftop air inlet)
Galvanized steel vent pipe with joints and seams sealed as
specified in this section.
Type “B” double-wall vent with joints and seams sealed as
specified in this section.
AL29-4C, stainless steel material to be sealed to
specification of its manufacturer.
*Plastic pipe may require an adapter (not provided) to
transition between the air inlet connection on the appliance
and the plastic air inlet pipe.
 WARNING Using air intake materials other than
those specified can result in personal
injury, death or property damage.
NOTICE

The use of double-wall vent or insulated
material for the combustion air inlet pipe is
recommended in cold climates to prevent
the condensation of airborne moisture in
the incoming combustion air.

The PVC, CPVC, or ABS air inlet pipe should be cleaned and
sealed with the pipe manufacturer’s recommended solvents
and standard commercial pipe cement for the material used.
The PVC, CPVC, ABS, Dryer Vent or Flex Duct air inlet pipe
should use a silicone sealant to ensure a proper seal at the
appliance connection and the air inlet cap connection. Dryer
vent or flex duct should use a screw type clamp to seal the vent
to the appliance air inlet and the air inlet cap. Proper sealing
of the air inlet pipe ensures that combustion air will be free of
contaminants and supplied in proper volume.
When a sidewall or vertical rooftop combustion air supply
system is disconnected for any reason, the air inlet pipe must
be resealed to ensure that combustion air will be free of
contaminants and supplied in proper volume.
 DANGER

Failure to properly seal all joints and seams
as required in the air inlet piping may
result in flue gas recirculation, spillage
of flue products and carbon monoxide
emissions causing severe personal injury
or death.

Sealing of Type “B” double-wall vent material or galvanized
vent pipe material used for air inlet piping on a sidewall or
vertical rooftop Combustion Air Supply System:
a. Seal all joints and seams of the air inlet pipe using either
Aluminum Foil Duct Tape meeting UL Standard 723 or
181A-P or a high quality UL Listed silicone sealant such as
those manufactured by Dow Corning or General Electric.
b. Do not install seams of vent pipe on the bottom of
horizontal runs.
c. Secure all joints with a minimum of three (3) sheet metal
screws or pop rivets. Apply Aluminum Foil Duct Tape or
silicone sealant to all screws or rivets installed in the vent
pipe.
d. Ensure that the air inlet pipes are properly supported.

Installation & Operation Manual

General venting

Optional room air
NOTICE

Optional room air is intended for
commercial applications. Combustion air
piping to the outside is recommended for
residential applications.

Commercial applications utilizing the Knight wall mount
boiler may be installed with a single pipe carrying the flue
products to the outside while using combustion air from
the equipment room. In order to use the room air venting
option the following conditions and considerations must be
followed.
•

•

The unit MUST be installed with the appropriate
room air kit (Table 3C).
•
The equipment room MUST be provided with
properly sized openings to assure adequate
combustion air. Please refer to instructions provided
with the room air kit.
•
There will be a noticeable increase in the noise level
during normal operation from the inlet air opening.
•
Using the room air kit makes the unit vulnerable
to combustion air contamination from within
the building. Please review Section 1, Prevent
Combustion Air Contamination, to ensure proper
installation.
Vent system and terminations must comply with the
standard venting instructions set forth in this manual.

When utilizing the single pipe method,
 WARNING provisions for combustion and ventilation
air must be in accordance with Air for
Combustion and Ventilation, of the latest
edition of the National Fuel Gas Code,
ANSI Z223.1, in Canada, the latest edition
of CGA Standard B149 Installation Code for
Gas Burning Appliances and Equipment, or
applicable provisions of the local building
codes.
Table 3C Optional Room Air Kit
Model
55 - 110
55 - 285
199 - 399

Vent Size
2"
3"
4"

Kit Number
KIT30051
KIT30052
KIT30053

Air contamination
Pool and laundry products and common household and hobby
products often contain fluorine or chlorine compounds.
When these chemicals pass through the boiler, they can form
strong acids. The acid can eat through the boiler wall, causing
serious damage and presenting a possible threat of flue gas
spillage or boiler water leakage into the building.
Please read the information given in Table 1A, page 10,
listing contaminants and areas likely to contain them. If
contaminating chemicals will be present near the location of
the boiler combustion air inlet, have your installer pipe the
boiler combustion air and vent to another location, per this
manual.
 WARNING

If the boiler combustion air inlet is located
in a laundry room or pool facility, for
example, these areas will always contain
hazardous contaminants.

 WARNING

To prevent the potential of severe personal
injury or death, check for areas and
products listed in Table 1A, page 10 before
installing the boiler or air inlet piping.
If contaminants are found, you MUST:
• Remove contaminants permanently.
—OR—
• Relocate air inlet and vent
terminations to other areas.

Installation & Operation Manual

General venting

(continued)

PVC/CPVC

This product has been approved for use with the PVC/CPVC
vent materials listed in Table 3D.
Installing vent and air piping

 WARNING The vent connection to the appliance must
be made with the starter piece provided
with the appliance if PVC/CPVC vent is to
be used. The field provided vent fittings
must be cemented to the CPVC pipe section
using an “All Purpose Cement” suitable for
PVC and CPVC pipe. Use only the vent
materials, primer, and cement specified in
Table 3D to make the vent connections.
Failure to follow this warning could result
in fire, personal injury, or death.
NOTICE

NOTICE

 WARNING

Use only cleaners, primers, and solvents
that are approved for the materials which
are joined together.
All PVC vent pipes must be glued, properly
supported, and the exhaust must be
pitched a minimum of a 1/4 inch per foot
back to the boiler (to allow drainage of
condensate).
Insulation should not be used on PVC
or CPVC venting materials. The use of
insulation will cause increased vent wall
temperatures, which could result in vent
pipe failure.

Work from the boiler to vent or air termination. Do not
exceed the lengths given in this manual for the air or vent
piping.
Cut pipe to the required lengths and deburr the inside
and outside of the pipe ends.

Chamfer outside of each pipe end to ensure even
cement distribution when joining.

Clean all pipe ends and fittings using a clean dry rag.
(Moisture will retard curing and dirt or grease will prevent
adhesion.)

Dry fit vent or air piping to ensure proper fit up before
assembling any joint. The pipe should go a third to
two-thirds into the fitting to ensure proper sealing after
cement is applied.

Priming and Cementing:
a. Handle fittings and pipes carefully to prevent
contamination of surfaces.
b. Apply a liberal even coat of primer to the fitting
socket and to the pipe end to approximately 1/2"
beyond the socket depth.
c. Apply a second primer coat to the fitting socket.
d.

e.
f.

Table 3D PVC/CPVC Vent Pipe, and Fittings

Approved PVC/CPVC Vent Pipe and Fittings
Item

Material

Standard

While primer is still wet, apply an even coat of
approved cement to the pipe equal to the depth of
the fitting socket along with an even coat of
approved cement to the fitting socket.
Apply a second coat of cement to the pipe.
While the cement is still wet, insert the pipe into
the fitting, if possible twist the pipe a 1/4 turn as
you insert it. NOTE: If voids are present,
sufficient cement was not applied and joint could
be defective.
Wipe excess cement from the joint removing ring
or beads as it will needlessly soften the pipe.

PVC Schedule 40, 80 ANSI/ASTM D1785
Vent pipe

PVC - DWV

ANSI/ASTM D2665

Figure 3-7 Near Boiler PVC/CPVC Venting

CPVC Schedule 40, 80 ANSI/ASTM F441
Vent fittings

PVC Schedule 40

ANSI/ASTM D2466

PVC Schedule 80

ANSI/ASTM D2467

CPVC Schedule 80

ANSI/ASTM F439

Pipe Cement / PVC
Primer
CPVC

CPVC STARTER PIECE

ANSI/ASTM D2564
ANSI/ASTM F493

NOTICE: DO NOT USE CELLULAR (FOAM) CORE PIPE
NOTE: In Canada, CPVC and PVC vent pipe, fittings and cement/
primer must be ULC-S636 certified.

Installation & Operation Manual

General venting

Polypropylene

 WARNING

This product has been approved for use with polypropylene
vent with the manufacturers listed in Table 3E.
All terminations must comply with listed options in this manual
and be a single-wall vent offering.
For use of flex pipe, it is recommended to have the vent material
in 32°F or higher ambient space before bending at installation.
No bends should be made to greater than 45° and ONLY
installed in vertical or near vertical installations.

NOTICE

For support and special connections required, see the
manufacturer's instructions. All vent is to conform to standard
diameter and equivalent length requirements established.

NOTICE

Table 3E Polypropylene Vent Pipe and Fittings

Use only the adapters and vent system listed
in Tables 3E and 3F. DO NOT mix vent
systems of different types or manufacturers.
Failure to comply could result in severe
personal injury, death, or substantial
property damage.
Installations must comply with applicable
national, state, and local codes. For
Canadian installation, polypropylene vent
must be listed as a ULC-S636 approved
system.
Installation of a polypropylene vent system
should adhere to the vent manufacturer’s
installation instructions supplied with the
vent system.

Approved Polypropylene Vent Manufacturers
Make

Model

Centrotherm Eco Systems
Duravent (M & G Group)

NOTICE

 WARNING

InnoFlue SW/Flex
PolyPro Single-Wall / PolyPro Flex

The installer must use a specific vent starter
adapter at the flue collar connection.
The adapter is supplied by the vent
manufacturer to adapt to its vent system.
See Table 3F for approved vent adapters.

Figure 3-8 Near Boiler Polypropylene Venting

All vent connections MUST be secured by
the vent manufacturer's joint connector
(FIG. 3-8).
Insulation should not be used on
polypropylene venting materials. The use
of insulation will cause increased vent wall
temperatures, which could result in vent
pipe failure.

JOINT CONNECTOR REQUIRED
AT ALL COMPONENT CONNECTIONS
OF VENT SYSTEM
POLYPROPYLENE ADAPTER
W/FLUE CLAMP

IMG00130

Table 3F Approved PolypropyleneTerminations

Duravent Polypro

Centrotherm InnoFlue SW

Model
55 - 85
110 - 285
399

Polypropylene
Adapter
ISAG0202 w/
IAFC02
ISAG0303 w/
IAFC03
ISAG0404 w/
IAFC04

Joint
Connector

Sidewall
Retaining
Bracket*

IANS02

IATP0202

ISTAGL0202

2PPS-AD w/PPS-PAC

2PPS-LB

2PPS-HLK

IANS03

IATP0303

ISTAGL0303

3PPS-AD w/PPS-PAC

3PPS-LB

3PPS-HLK

IANS04

IATP0404

ISTAGL0404

4PPS-AD w/PPS-PAC

4PPS-LB

4PPS-HLK

Sidewall Adapter* Polypropylene Adapter

* These parts are only needed if the sidewall termination assembly is used (see FIG. 4-4B on page 24).

Joint
Sidewall Kit*
Connector

Installation & Operation Manual

General venting

(continued)

Stainless steel vent

NOTICE

This product has been approved for use with stainless steel
using the manufacturers listed in Table 3G.
 WARNING

Use only the materials, vent systems, and
terminations listed in Tables 3G and 3H.
DO NOT mix vent systems of different
types or manufacturers. Failure to comply
could result in severe personal injury,
death, or substantial property damage.

Installation of a stainless steel vent
system should adhere to the stainless
steel vent manufacturer’s installation
instructions supplied with the vent
system.

Figure 3-9 Near Boiler Stainless Steel Venting
VENT

The installer must use a specific vent starter
adapter at the flue collar connection,
supplied by the vent manufacturer to
adapt to its vent system. See Table 3H for
approved vent adapters. Discard CPVC
starter piece.

NOTICE

REPLACE APPLIANCE
SECURED CPVC ADAPTER
WITH APPROPRIATE
STAINLESS STEEL ADAPTER
FROM TABLE 3H

Installations must comply with applicable
national, state, and local codes. Stainless
steel vent systems must be listed as a
UL-1738 approved system for the United
States and a ULC-S636 approved system
for Canada.

NOTICE

Table 3G Stainless Steel Vent Pipe and Fittings
Approved Stainless Steel Vent Manufacturers
Make
Model
Dura Vent (M & G Group)

FasNSeal Vent / FasNSeal Flex* Vent

Z-Flex (Nova Flex Group)

Z-Vent

Heat Fab (Selkirk Corporation)

Saf-T Vent

*Use of FasNSeal Flex smooth inner wall vent is to be used in vertical or near vertical sections only, taking precaution to ensure
no sagging occurs of the vent system. Connect to the FasNSeal rigid vent using specially designed adapters and sealing method,
see manufacturer’s instructions.
Table 3H Approved Stainless Steel (S.S.) Terminations and Adapters

Model

ProTech

Heat Fab

Z Flex

FasNSeal

Saf-T Vent

Z-Vent

Intake
Intake
Boiler
Flue
Boiler
Flue
Air
Air
Adapter Termination
Adapter Termination
Termination
Termination

55 - 85

303005

110 -285

303006

399

303007

FSBS3
FSRC3(R.C)

303889

FSBS4
FSRC4(R.C)

FSAIH04
303888

WH0002
WH0003
WH0004

9392
5300CI

9314TERM

9492
5400CI

9414TERM

Boiler
Adapter

Flue
Termination

Intake Air
Termination

2SVAKA02

2SVSTP03
2SVSRCX03

2SVSTEX0390

2SVAKA03
2SVAKA04

2SVSTP04
2SVSTEX0490
2SVSRCX04

Installation & Operation Manual

Sidewall direct venting

Vent/air termination – sidewall
 WARNING

Follow instructions below when
determining vent location to avoid
possibility of severe personal injury,
death, or substantial property damage.

 WARNING

A gas vent extending through an exterior
wall shall not terminate adjacent to a wall
or below building extensions such as eaves,
parapets, balconies, or decks. Failure to
comply could result in severe personal
injury, death, or substantial property
damage.

Figure 4-1A PVC/CPVC/Polypropylene Sidewall
Termination of Air and Vent
TO BOILER
INTAKE AIR
CONNECTION

FROM BOILER
VENT PIPE
CONNECTION
12"
MIN
TO
OVERHANG

POSSIBLE ORIENTATIONS

VENT / AIR
TERMINATION

Determine location

12"
MIN
GRADE OR
SNOW LINE

Locate the vent/air terminations using the following guidelines:
1. The total length of piping for vent or air must not exceed Table 4A Sidewall Vent Kit
the limits given in the General Venting Section on page 16
Model Kit Number
of this manual.
2.

Vent Size

55 - 110
KIT30044
2 inch vent
You must consider the surroundings when terminating
the vent and air:
110 - 285
KIT30045
3 inch vent
a. Position the vent termination where vapors will
399
KIT30046
4 inch vent
not damage nearby shrubs, plants or air
conditioning equipment or be objectionable.
If using the alternate sidewall termination:
b. The flue products will form a noticeable plume as 3. The air piping must terminate in a down-turned elbow
they condense in cold air. Avoid areas where the
as shown in FIG. 4-1B. This arrangement avoids
plume could obstruct window views.
recirculation of flue products into the combustion air
c. Prevailing winds could cause freezing of
stream.
condensate and water/ice buildup where flue
4. The vent piping must terminate in an elbow pointed
products impinge on building surfaces or plants.
outward or away from the air inlet, as shown in FIG. 4-1B.
d. Avoid possibility of accidental contact of flue
Do not exceed the maximum lengths of the
products with people or pets.
 WARNING
outside vent piping shown in FIG. 4-1B.
e. Do not locate the terminations where wind eddies
Excessive length exposed to the outside
could affect performance or cause recirculation,
could cause freezing of condensate in the
such as inside building corners, near adjacent
vent pipe, resulting in potential boiler
buildings or surfaces, window wells, stairwells,
shutdown.
alcoves, courtyards, or other recessed areas.

 WARNING
f.
g.

Figure 4-1B Alternate PVC/CPVC/ Polypropylene Sidewall
Sidewall vent and air inlet terminations Termination of Air and Vent w/Field Supplied Fittings
must terminate in the same pressure zone.

Do not terminate above any door or window.
Condensate can freeze, causing ice formations.
Locate or guard vent to prevent condensate damage
to exterior finishes.

TO BOILER
INTAKE AIR
CONNECTION

BIRD SCREEN

FROM BOILER
VENT PIPE
CONNECTION

12” MIN
15” MAX

TERMINATION
PLATE

12”
MIN
BIRD SCREEN
GRADE OR
SNOW LINE

Installation & Operation Manual

Sidewall direct venting

(continued)

Vent/air termination – sidewall

Figure 4-1C Alternate PVC/CPVC/SS/ Polypropylene Venting
Arrangement (if Space Allows) w/Field Supplied Fittings
TO BOILER
INTAKE AIR
CONNECTION

6. Locate terminations so they are not likely to be damaged
by foreign objects, such as stones or balls, or subject to
buildup of leaves or sediment.

COUPLING

Figure 4-2A Clearance to Gravity Air Inlets
12” MIN
15” MAX

FROM BOILER
VENT PIPE
CONNECTION

BIRD SCREEN

12"
MIN.

12”
MIN
BIRD
SCREEN
GRADE OR
SNOW LINE
ALTERNATE VENTING ARRANGEMENT
(IF SPACE PERMITS)

VENT / AIR
TERMINATION

Figure 4-1D Alternate SS Venting Arrangement Typical Stainless Steel Sidewall Termination of Air and
Vent w/Field Supplied Fittings, Utilizing a Hood Intake
BIRD SCREEN
TO BOILER
INTAKE AIR
CONNECTION

12"
MIN.
12"
MIN.

Figure 4-2B Alternate Clearance to Gravity Air Inlets w/
Field Supplied Fittings

12" (305 MM) MIN
15" (381 MM) MAX

FROM BOILER
VENT PIPE
CONNECTION
12”
MIN.

12" (305 MM) MIN

GRADE OR
SNOW LINE

BIRD
SCREEN
(TYPICAL)

Maintain clearances as shown in FIG.’s 4-1A thru 4-3B,
12”
MIN.
pages 22 - 24. Also maintain the following:
12”
a. Vent must terminate:
MIN.
• At least 6 feet from adjacent walls.
• No closer than 12 inches below roof overhang.
Figure 4-3A Clearance to Forced Air Inlets
• At least 7 feet above any public walkway.
IF LESS
THAN 10’
• At least 3 feet above any forced air intake within
10 feet.
VENT / AIR
36"
• No closer than 12 inches below or horizontally
TERMINATION
MIN.
from any door or window or any other gravity air
inlet.
b. Air inlet must terminate at least 12 inches above
FORCED AIR
INLET
grade or snow line; at least 12 inches below the vent
termination; and the vent pipe must not extend
more than 24 inches vertically outside the building
as shown in FIG. 4-1B. Condensate could freeze and
7' MIN. ABOVE ANY
block vent pipe.
PUBLIC WALKWAY
c. Do not terminate closer than 4 feet horizontally
from any electric meter, gas meter, regulator, relief
valve, or other equipment. Never terminate above or
below any of these within 4 feet horizontally.

Installation & Operation Manual

Sidewall direct venting

Figure 4-3B Alternate Clearance to Forced Air Inlets w/
Field Supplied Fittings

Figure 4-4A PVC/CPVC Sidewall Termination Assembly

IF LESS
THAN 10’

36”
MIN.

VENT

FORCED AIR
INLET

7’ MIN. ABOVE ANY
PUBLIC WALKWAY

BIRD
SCREEN
(TYPICAL)

AIR PIPING

AIR

CENTERLINE WIDTH

VENT PIPING
VENT PLATE
WALL PLATE

VENT CAP

GALVANIZED
THIMBLE

Prepare wall penetrations
1.

4.
5.
6.

7.
8.

Use the factory supplied wall plate as a template to locate
the vent and air intake holes and mounting holes.
Air pipe penetration:
a. Cut a hole for the air pipe. Size the air pipe hole as
close as desired to the air pipe outside diameter.
Vent pipe penetration:
a. Cut a hole for the vent pipe. For either combustible
or noncombustible construction, size the vent pipe
hole with at least a 1/2 inch clearance around the
vent pipe outer diameter:
• 4½ inch hole for 3 inch vent pipe
• 5½ inch hole for 4 inch vent pipe
Drill 3/16" diameter holes for inserting the plastic anchors
into the wall.
For Polypropylene Only: Install the vent and air intake
sidewall adapters from Table 3F on page 20 into the vent
plate. Slide the sidewall retaining bracket down the
sidewall adapters flush to the vent plate (FIG. 4-4B).
For PVC/CPVC Only: Install the vent and air intake
piping through the wall into the vent plate openings.
Use RTV silicone sealant to seal the air pipe. Use the
cement/primer listed in Table 3D on page 19 to seal the
vent pipe.
Mount and secure the vent plate to the wall, using stainless
steel screws.
Seal all gaps between the pipes and wall. Seal around the
plate to the wall assuring no air gaps.
Assemble the vent cap to the vent plate (see FIG.'s 4-4A
and 4-4B). Insert the stainless steel screws into the vent
cap screw hole openings and securely attach the vent cap
to the vent plate.
Seal all wall cavities.
PVC/CPVC terminations are designed to accommodate
any wall thickness of standard constructions per the
directions found in this manual.
Stainless steel terminations are designed to penetrate
walls with a thickness up to 9.25 inches of standard
construction.

Table 4B Sidewall Vent Centerline Dimensions

Model

Air

Vent

Centerline Width

151 - 200

5 5/8"

286

5 5/8"

Figure 4-4B Polypropylene Sidewall Termination Assembly
SIDEWALL
ADAPTER
(AIR)

WALL
PLATE
SIDEWALL
RETAINING
PLATE

VENT
PLATE
VENT
CAP
SIDEWALL
ADAPTER
(VENT)

GALVANIZED
THIMBLE

IMG00085

Installation & Operation Manual

Sidewall direct venting

(continued)

Prepare wall penetrations (Alternate Field Supplied Option)
1.

3.
4.
5.

Air pipe penetration:
a. Cut a hole for the air pipe. Size the air pipe hole as
close as desired to the air pipe outside diameter.
Vent pipe penetration:
a. Cut a hole for the vent pipe. For either combustible
or noncombustible construction, size the vent pipe
hole with at least a 1/2 inch clearance around the vent
pipe outer diameter:
• 4½ inch hole for 3 inch vent pipe
• 5½ inch hole for 4 inch vent pipe
b. Insert a galvanized metal thimble in the vent pipe
hole as shown in FIG. 4-4C.
Use a sidewall termination plate as a template for correct
location of hole centers.
Follow all local codes for isolation of vent pipe when
passing through floors or walls.
Seal exterior openings thoroughly with exterior caulk.

Figure 4-5A Multiple Vent Terminations (must also
comply with Figure 4-1A)
12" MIN. BETWEEN EDGE OF AIR
INLET AND ADJACENT VENT OUTLET
VENT
AIR

VENT / AIR
TERMINATION

Figure 4-5B Alternate Multiple Vent Terminations w/Field
Supplied Fittings (must also comply with Figure 4-1B)

Figure 4-4C Alternate Sidewall Termination Assembly
w/Field Supplied Fittings
ELBOW
AIR PIPING
VENT PIPING

BIRD SCREEN

GALVANIZED
THIMBLE

ELBOW
SIDEWALL
TERMINATION PLATE

BIRD SCREEN

Multiple vent/air terminations
1. When terminating multiple Knight wall mount boilers
terminate each vent/air connection as described in this
manual (FIG. 4-5A).
 WARNING All vent pipes and air inlets must terminate
at the same height to avoid possibility
of severe personal injury, death, or
substantial property damage.
2. Place wall penetrations to obtain minimum clearance
of 12 inches between edge of air inlet and adjacent vent
outlet, as shown in FIG. 4-5A for U.S. installations. For
Canadian installations, provide clearances required by
CSA B149.1 Installation Code.
3. The air inlet of a Knight wall mount boiler is part of a
direct vent connection. It is not classified as a forced air
intake with regard to spacing from adjacent boiler vents.

Installation & Operation Manual

Sidewall direct venting

Sidewall termination – optional concentric vent
Description and usage
Lochinvar offers optional concentric combustion air and vent
pipe termination kits (Factory Kit #CVK3003 for 3" diameter
- models 155 - 199, #CVK3008 for 2" diameter - models 55 110, or #CVK3007 for 4" diameter - models 285 - 399). Both
combustion air and vent pipes must attach to the termination
kit. The termination kit must terminate outside the structure
and must be installed as shown below in FIG. 4-6.
The required combustion vent pipe and fittings are listed in
Table 3D, on page 19 of this manual.
Figure 4-6 Concentric Sidewall Termination

3. Cut one (1) hole (5 inch diameter for #CVK3003
installations, 4 inch diameter for #CVK3008, or 7 inch
diameter for #CVK3007 installations) into the structure to
install the termination kit.
4. Partially assemble the concentric vent termination kit.
Clean and cement using the procedures found in these
instructions.
a. Cement the Y concentric fitting to the larger kit pipe
(FIG. 4-7).
b. Cement the rain cap to the smaller diameter kit pipe
(FIG. 4-7).
Figure 4-7 Kit Contents - CVK3008 & CVK3003
(reference Table 3B on page 16)

Figure 4-8 Kit Contents - CVK3007 (reference Table
3B on page 16)
RAIN CAP

Sidewall termination installation
1. Determine the best location for the termination kit (see
FIG. 4-6).

6" (152 MM) TO 4" (102 MM) REDUCER
6" (152 MM) DIA.

2. Reference the Determine Location Section on page 22 of this
manual for general termination considerations.
6" (152 MM) DIA.

4" (102 MM) DIA.
"Y" CONCENTRIC
FITTING
6" (152 MM) DIA.
"FLEXIBLE" PIPE
COUPLING

4" CONCENTRIC
VENT KIT

Installation & Operation Manual

Sidewall direct venting

(continued)

Sidewall termination – optional concentric vent models
Figure 4-9 2" and 3" Concentric Vent Dimensional
Drawing (reference Table 3D on page 19)

Figure 4-10 4" Concentric Vent Dimensional Drawing
(reference Table 3D on page 19)
"C" DIA.

"B" DIA.

"D"

3"
(76 MM)

"E"

"G"

"H" DIA.

"B" DIA. PVC
VENT / EXHAUST

A
60"

"F"

B
4"

(1524 MM) (102 MM)

C
6"

D
21 1/8"

(152 MM) (537 MM)

E
10"

F
7 5/8"

G
3"

H
6 5/8"

(254 MM)

(194 MM)

(76 MM)

(168 MM)

Instead of cementing the smaller pipe to
the rain cap, a field-supplied stainless steel
screw may be used to secure the two (2)
components together when field disassembly
is desired for cleaning (see FIG. 4-11).

5. Install the Y concentric fitting and pipe assembly through
the structure’s hole.

When using the alternate screw assembly
 WARNING method, drill a clearance hole in the rain
cap and a pilot hole in the vent pipe for
the screw size being used. Failure to drill
adequate holes may cause cracking of PVC
components, allowing combustion products
to be recirculated. Failure to follow this
warning could result in personal injury or
death.

6. Install the rain cap and small diameter pipe assembly
into the Y concentric fitting and large pipe assembly.
Ensure small diameter pipe is bottomed and cemented
in the Y concentric fitting for #CVK3003 and 3008
installations and fastened tightly into the rubber adapter
for #CVK3007 installations.

NOTICE

 WARNING

Do not operate the appliance with the rain
cap removed or recirculation of combustion
products may occur. Water may also collect
inside the larger combustion air pipe and
flow to the burner enclosure. Failure to
follow this warning could result in product
damage or improper operation, personal
injury, or death.

NOTICE

Do not allow insulation or other materials
to accumulate inside the pipe assembly
when installing through the hole.

7. Secure the assembly to the structure as shown in FIG.
4-12 using field-supplied metal strapping or equivalent
support material.
Ensure termination location clearance
NOTICE
dimensions are as shown in FIG. 4-6.
NOTICE

Figure 4-11 Rain Cap to Vent Pipe Alternate Assembly

NOTICE

If assembly needs to be extended to allow
sidewall thickness requirement, the two (2)
pipes supplied in the kit may be replaced
by using the same diameter, field-supplied
SDR-26 PVC (D2241) pipe for CVK3003
and 3008, and standard schedule 40 PVC
for CVK3007. Do not extend dimension
D more than 60 inches (see FIG. 4-9 and
FIG. 4-10).
If assembly needs to be reduced, dimension
D can be as short as possible.

Installation & Operation Manual

Sidewall direct venting

Sidewall termination – optional concentric vent
Figure 4-12 Concentric Vent Sidewall Attachment

CAUTION

DO NOT use field-supplied couplings to
extend pipes. Airflow restriction will occur
and may cause intermittent operation.

8. Cement appliance combustion air and vent pipes to the
concentric vent termination assembly. See FIG. 4-12 for
proper pipe attachment.
9. Operate the appliance one (1) heat cycle to ensure
combustion air and vent pipes are properly connected to
the concentric vent termination connections.

Multiventing sidewall terminations
When two (2) or more direct vent appliances are vented near
each other, each appliance must be individually vented (see
FIG. 4-13). NEVER common vent or breach vent this appliance.
When two (2) or more direct vent appliances are vented near
each other, two (2) vent terminations may be installed as shown
in FIG. 4-13. It is important that vent terminations be made as
shown to avoid recirculation of flue gases.

12"
MINIMUM
VENT

COMBUSTION
AIR
Figure 4-13 Concentric Vent and Combustion Air Termination

Installation & Operation Manual

Vertical direct venting

Vent/air termination – vertical
 WARNING

Figure 5-1A PVC/CPVC/Polypropylene Vertical
Termination of Air and Vent

Follow instructions below when
determining vent location to avoid
possibility of severe personal injury, death
or substantial property damage.

ALTERNATE INTAKE LOCATIONS:
INTAKE PIPES MAY BE LOCATED
ANYWHERE WITHIN 24” OF VENT
PIPE

Determine location
BIRD SCREEN
(TYPICAL)

Locate the vent/air terminations using the following
guidelines:
1. The total length of piping for vent or air must not exceed
the limits given in the General Venting Section on page
16 of this manual.

VENT
COUPLING
(FIELD SUPPLIED)
6” MINIMUM
ABOVE ROOF /
SNOW LINE

2. Prepare the vent termination and the air termination
elbow (FIG. 5-1A) by inserting bird screens. Bird screens
should be obtained locally.
3. The vent must terminate at least 3 feet above the highest
place in which the vent penetrates the roof and at least
2 feet above any part of a building within 10 horizontal
feet.
4. The air piping must terminate in a down-turned 180°
return pipe no further than 2 feet from the center of the
vent pipe. This placement avoids recirculation of flue
products into the combustion air stream.

VENT OUTLET
12” MINIMUM
ABOVE AIR INLET

Figure 5-1B Stainless Steel Vertical Termination of Air
and Vent
ALTERNATE INTAKE LOCATIONS:
INTAKE PIPES MAY BE LOCATED
ANYWHERE WITHIN 24” (610 MM)
OF VENT PIPE

5. The vent piping must terminate in an up-turned coupling
as shown in FIG. 5-1A. The top of the coupling must
be at least 1 foot above the air intake. When the vent
termination uses a rain cap as illustrated in FIG. 5-1B
maintain at least 36" (914 mm) above the air inlet. The
air inlet pipe and vent pipe can be located in any desired
position on the roof, but must always be no further than
2 feet (.6 m) apart and with the vent termination at least
1 foot for PVC and 3 feet for stainless steel, above the air
intake.
6. Maintain the required dimensions of the finished
termination piping as shown in FIG. 5-1A.
7. Do not extend exposed vent pipe outside of building
more than shown in this document. Condensate could
freeze and block vent pipe.
 WARNING

Rooftop vent and air inlet terminations
must terminate in the same pressure
zone, unless vertical vent sidewall air is
set up as shown in the General Venting Vertical Vent, Sidewall Air Section.

COMBUSTION
AIR

BIRD SCREEN
(TYPICAL)

VENT

6" (152 MM) MINIMUM
ABOVE ROOF /
SNOW LINE
COM,BUSTION
AIR

VENT OUTLET
36” (914 MM) MINIMUM
ABOVE AIR INLET

8. Locate terminations so they are not likely to be damaged by
foreign objects or subject to buildup of leaves or sediment.

Prepare roof penetrations
1.

Air pipe penetration:
a. Cut a hole for the air pipe. Size the air pipe hole as
close as desired to the air pipe outside diameter.

Vent pipe penetration:
a. Cut a hole for the vent pipe. For either combustible
or noncombustible construction, size the vent pipe
hole with at least a 1/2 inch clearance around the
vent pipe outer diameter:
• 3½ inch hole for 2 inch vent pipe
• 4½ inch hole for 3 inch vent pipe
b. Insert a galvanized metal thimble in the vent pipe
hole.

Installation & Operation Manual

Vertical direct venting

Prepare roof penetrations (continued)
3. Space the air and vent holes to provide the minimum
spacing shown in FIG. 5-1A, page 29.
4. Follow all local codes for isolation of vent pipe when
passing through floors, ceilings, and roofs.
5. Provide flashing and sealing boots sized for the vent pipe
and air pipe.

Multiple vent/air terminations
1. When terminating multiple Knight wall mount boilers,
terminate each vent/air connection as described in this
manual (FIG. 5-2).
 WARNING

Terminate all vent pipes at the same height
and all air pipes at the same height to
avoid possibility of severe personal injury,
death, or substantial property damage.

2. Place roof penetrations to obtain minimum clearance of
12 inches between edge of air intake elbow and adjacent
vent pipe of another boiler for U.S. installations (see
FIG. 5-2). For Canadian installations, provide clearances
required by CSA B149.1 Installation Code.

Vertical termination – optional
concentric vent
Description and usage
Lochinvar offers an optional concentric combustion air and
vent pipe termination kit. Both combustion air and vent
pipes must attach to the termination kit. The termination
kit must terminate outside the structure and must be
installed as shown in FIG. 5-4.
Field supplied pipe and fittings are required to complete
the installation.
The required combustion air and vent pipe fittings are
listed in Table 3D, on page 19 of this manual.
Vertical termination installation
1. See Section 5, Vertical Direct Venting - Determine
Location (where applicable).
Figure 5-4 Concentric Vertical Termination

3. The air inlet of a Knight wall mount boiler is part of a
direct vent connection. It is not classified as a forced air
intake with regard to spacing from adjacent boiler vents.
Figure 5-2 Vertical Terminations with Multiple Boilers

12” MINIMUM VERTICALLY
FROM VENT OUTLET TO
ANY AIR INLET
12” MINIMUM FROM EDGE OF AIR
INTAKE PIPE TO ADJACENT VENT
PIPE FROM ANOTHER BOILER

Figure 5-5 Do Not Install U-Bend to Rain Cap

Figure 5-3 Alternate Vertical Terminations with Multiple
Boilers

2. Cut one (1) hole (5 inch diameter for #CVK3003
installations or 4 inch diameter for #CVK3008 installations)
into the structure to install the termination kit.
3. Partially assemble the concentric vent termination kit.
Clean and cement following the cleaning procedures in
these instructions.
a. Cement the Y concentric fitting to the larger
diameter kit pipe (see FIG. 4-7, page 26).
b. Cement rain cap to the smaller diameter kit pipe (see
FIG. 4-7, page 26).

Installation & Operation Manual

Vertical direct venting
NOTICE

(continued)

Instead of cementing the smaller pipe to
the rain cap, a field supplied stainless steel
screw may be used to secure the two (2)
components together when field disassembly
is desired for cleaning (see FIG. 4-9, page
27).

 WARNING When using the alternate screw assembly
method, drill a clearance hole in the rain
cap and a pilot hole in the vent pipe for
the screw size being used. Failure to drill
adequate holes may cause cracking of PVC
components, allowing combustion products
to be recirculated. Failure to follow this
warning could result in personal injury or
death.
Do not operate the appliance with
 WARNING
the rain cap removed or recirculation
of combustion products may occur.
Water may also collect inside the larger
combustion air pipe and flow to the
burner enclosure. Failure to follow this
warning could result in product damage
or improper operation, personal injury,
or death.
4. Install the Y concentric fitting pipe assembly through the
structure’s hole and field supplied roof boot/flashing.
NOTICE

Do not allow insulation or other materials
to accumulate inside the pipe assembly
when installing through the hole.

5. Secure the assembly to the roof structure as shown
below in FIG. 5-6 using field supplied metal strapping or
equivalent support material.
Figure 5-6 Concentric Vent Roof Installation

NOTICE

CAUTION

Ensure termination height is above the
roof surface or anticipated snow level (12
inches in U.S.A. or 18 inches in Canada) as
shown in FIG. 5-4, page 30.
If assembly is too short to meet height
requirement, the two (2) pipes supplied
in the kit may be replaced by using the
same diameter, field supplied SDR-26 PVC
(D2241) pipe. Add standard schedule 40
PVC pipe for #CVK3007 Do not extend
dimension D more than 60 inches (see FIG.
4-9 and FIG. 4-10, page 27).
DO NOT use field-supplied couplings to
extend pipes. Airflow restriction will occur.

Install the rain cap and the small diameter pipe assembly
into the roof penetration assembly. Ensure the small
diameter pipe is cemented and bottomed in the Y
concentric fitting.

Cement the appliance combustion air and vent pipes to
the concentric vent termination assembly. See FIG. 5-6
for proper pipe attachment.

Operate the appliance through one (1) heat cycle to ensure
combustion air and vent pipes are properly connected to
the concentric vent termination connections.
Multiventing vertical terminations
When two (2) or more direct vent appliances are vented near
each other, each appliance must be individually vented (see
FIG. 5-7). NEVER common vent or breach vent this appliance.
When two (2) or more direct vent appliances are vented near
each other, two (2) vent terminations may be installed as shown
in FIG. 5-7. It is important that vent terminations be made as
shown to avoid recirculation of flue gases.
Figure 5-7 Concentric Vent and Combustion Air Vertical
Termination
12”
MINIMUM

COMBUSTION
AIR (TYPICAL)

12” (18” FOR CANADA)
MINIMUM CLEARANCE
ABOVE HIGHEST
ANTICIPATED SNOW
LEVEL. MAXIMUM OF
24” ABOVE ROOF.

Installation & Operation Manual

Vertical direct venting

Alternate vertical concentric
venting
This appliance may be installed with a concentric vent
arrangement where the vent pipe is routed through an
existing unused venting system; or by using the existing
unused venting system as a chase for vent and combustion
air routing.

Concentric Venting Arrangement
The venting is to be vertical through the roof. The annular
space between the O.D. of the vent pipe and the I.D. of the
existing unused venting system is utilized for the combustion
air source.
The minimum size of the existing vent system required to
achieve enough annular space for combustion air can be found
in Table 5A.
The upper and lower termination as well as any other unsealed
joints in the existing vent system must be sealed to ensure that
all combustion air is drawn from under the vent cap as shown
in FIG.’s 5-8 and 5-9.

Figure 5-8 Concentric Vent Example 1
FLUE EXHAUST

SEAL
COMBUSTION AIR
AIR INLET
W/ SCREEN
EXISTING

12”
MIN.

SEAL
SEALED
CAP
FLUE OUTLET

*For concept illustration only. Individual installations
may vary due to job site specific equipment.

Figure 5-9 Concentric Vent Example 2
SEAL

COMBUSTION AIR

Approved venting materials must be used as specified in Table
3D on page 19.
Follow all vent / air termination and clearance requirements
per this section to the appropriate example. Installation must
comply with local requirements and with the National Fuel
Gas Code.

FLUE EXHAUST

SEAL

EXISTING
SEAL
SEALED
CAP
FLUE OUTLET

The maximum allowable equivalent vent and air intake
lengths for this venting arrangement are to be determined
from the General Venting Section.
If an existing unused venting system is converted for use
with this method of concentric venting, the installer must
ensure that the existing venting system is clean and free from
particulate contamination that will harm this appliance and
cause increased nuisance calls or maintenance. See Table 1A
on page 10 for a list of corrosive contaminants and sources.
Two example scenarios of a concentric venting arrangement
are shown for illustrative purposes in FIG.’s 5-8 and 5-9.

*For concept illustration only. Individual installations may
vary due to job site specific equipment.

Existing vent as a chase
Follow all existing termination and clearance requirements and
allowable pipe lengths. Use only approved venting materials
listed in the General Venting Section of this manual.

Figure 5-10 Existing Vent as a Chase
Table 5A Alternate Vertical Concentric Vent / Chase Sizes

Vent / Air Inlet Size

Minimum Existing
Vent / Chase Size

2"
3"
4"

4"
5"
7"

FLUE EXHAUST
AIR INLET

SEAL

EXISTING
CAP

SEAL
FLUE OUTLET

*For concept illustration only. Individual installations
may vary due to job site specific equipment.

Installation & Operation Manual

Hydronic piping

System water piping methods

General piping information

The Knight wall mount is designed to function in a closed
loop pressurized system not less than 12 psi. A temperature
and pressure gauge is included to monitor system pressure
and outlet temperature and should be located on the boiler
outlet.

Basic steps are listed below along with illustrations on the
following pages (FIG.’s 6-3 through 6-12), which will guide
you through the installation of the Knight wall mount boiler
(reference FIG.’s 6-1A and 6-1B).
1.

Connect the system return marked “Inlet”.

It is important to note that the boiler has a minimal
amount of pressure drop and must be figured in when
sizing the circulators. Each boiler installation must have
an air elimination device, which will remove air from
the system. Install the boiler so the gas ignition system
components are protected from water (dripping, spraying,
etc.) during appliance operation for basic service of circulator
replacement, valves, and others.

Connect the system supply marked “Outlet”.

Install purge and balance valve or shutoff valve and drain
on system return to purge air out of each zone.

Install a backflow preventer on the cold feed make-up water
line.

Install a pressure reducing valve on the cold feed makeup water line, (15 psi nominal). Check temperature and
pressure gauge (shipped separately), which should read a
minimum pressure of 12 psi.

Install a circulator as shown on the piping diagrams in this
section. Make sure the circulator is properly sized for the
system and friction loss.

Install an expansion tank on the system supply. Consult the
tank manufacturer’s instruction for specific information
relating to tank installation. Size the expansion tank for the
required system volume and capacity.

Install an air elimination device on the system supply.

Install a drain valve at the lowest point of the system.

Observe a minimum of a 1/4 inch clearance around all
un-insulated hot water pipes when openings around the pipes
are not protected by non-combustible materials.

Low water cutoff device
On a boiler installed above radiation level, some states and
local codes require a low water cutoff device at the time of
installation.

Chilled water system
If the boiler supplies hot water to heating coils in air handler
units, flow control valves or other devices must be installed to
prevent gravity circulation of heater water in the coils during
the cooling cycle. A chilled water medium must be piped in
parallel with the heater.

Freeze protection
Freeze protection for new or existing systems must use glycol
that is specially formulated for this purpose. This includes
inhibitors, which prevent the glycol from attacking the
metallic system components. Make certain to check that
the system fluid is correct for the glycol concentration and
inhibitor level. The system should be tested at least once
a year and as recommended by the producer of the glycol
solution. Allowance should be made for the expansion of the
glycol solution in the system piping.
 WARNING

Use only inhibited propylene glycol
solutions, which are specifically formulated
for hydronic systems. Ethylene glycol is
toxic and can attack gaskets and seals used
in hydronic systems.

10. This appliance is supplied with a relief valve sized in
accordance with ASME Boiler and Pressure Vessel Code,
Section IV (“Heating Boilers”). The safety relief valve is
installed at the factory located on the left-hand side of the
boiler. Pipe the discharge of the safety relief valve to prevent
injury in the event of pressure relief. Pipe the discharge to a
drain. Provide piping that is the same size as the safety relief
valve outlet. Never block the outlet of the safety relief valve.
See the *piping illustrations included in this section, FIG.’s 6-3
through 6-10 for suggested guidelines in piping the Knight wall
mount boiler with either zone valves or circulator pumps.
NOTICE

*Please note that these illustrations are
meant to show system piping concept only,
the installer is responsible for all equipment
and detailing required by local codes.

Installation & Operation Manual

Hydronic piping

Near boiler piping components
1. Boiler system piping:
Boiler system piping MUST be sized per the pipe
requirements listed in Table 6A. Reducing the pipe size
can restrict the flow rate through the boiler, causing
inadvertent high limit shutdowns and poor system
performance. Flow rates are based on 20 feet of piping,
4 - 90° elbows, and 2 - fully ported ball valves.
2. Boiler circulating pump:
A Grundfos UPS15-58FC pump for Models 55 - 155
and a Grundfos UPS26-99FC pump for Models 199 399 will be provided by the factory as the boiler circulation
pump based on 20 feet of piping, 4 - 90° elbows, and 2 - fully
ported ball valves.
Knight wall mount boilers are capable of controlling a
variable speed boiler circulator.
Variable speed
circulators MUST be sized to meet the specified
minimum flow requirements listed in FIG. 6-2 on page 36
at full speed.
3. Domestic hot water circulating pump:
Field supplied. The pump MUST be sized to meet
the specified minimum flow requirements listed in
FIG. 6-2. Consult the indirect water heater operating
guide to determine flow characteristics for the selected
product used.
4. Boiler isolation valves:
Field supplied. Full port ball valves are required. Failure
to use full port ball valves could result in a restricted flow
rate through the boiler.
5. Check valves:
Field supplied. Check valves are recommended for
installation as shown in FIG.’s 6-3 through 6-10. Failure
to install check valves could result in a reverse flow
condition during pump(s) off cycle.
6. Domestic indirect hot water isolation valves:
Field supplied.
Full port ball valves are
required. Failure to use full port ball valves could
result in a restricted flow rate through the boiler.
7. Anti-scald mixing valve:
Field supplied.
An anti-scald mixing valve is
recommended when storing domestic hot water above
115°F.
8. Unions:
Field supplied. Recommended for unit serviceability.
9. Temperature and pressure gauge:
Factory supplied. The temperature and pressure gauge is
shipped loose. It is the responsibility of the contractor to
install the temperature and pressure gauge on the boiler
water outlet.
10. Pressure relief valve:
Factory supplied. The pressure relief valve is sized to
ASME specifications.

11. Boiler purge valve:
Factory supplied. The boiler purge valve is used to
remove entrapped air from the heat exchanger during
start-up.
12. System temperature sensor:
Lochinvar supplies a system temperature sensor.
The sensor is to be installed in the heating loop
downstream from the boiler hot water piping and
heating loop junction. Typically the sensor will be
located far enough downstream to sense system diluted
water temperature.
13. Indirect water heaters:
The Knight wall mount boiler may be piped to an indirect
water heater to heat domestic hot water with the space heat
transfer medium. As depicted in the piping diagrams on
page 38 thru 47, there are two options when utilizing an
indirect water heater.
A. The space heating piping will branch off to flow the
space heat transfer medium through a single wall
heat exchanger coil inside the indirect water heater.
B. The indirect water heater is connected to the system
supply piping. A pump controlled by the Knight
(wall mount) boiler’s control will regulate the flow of
water through the indirect water heater. The indirect
water heater’s temperature will be regulated by the
Knight (wall mount) boiler’s control.
The Knight wall mount boiler is pre-configured to control
the operation of the DHW pump with Domestic Hot Water
Prioritization programming. The DHW programming is
designed to control and balance the space heating
demand by switching between DHW and space heating.
Lochinvar offers the Squire which is a series of indirect
water heaters. The Squire features a stainless steel vessel
with a single wall stainless steel heat exchanger.
 WARNING The National Standard Plumbing Code, the
National Plumbing Code of Canada and the
Uniform Plumbing Code limit the pressure
of the heat transfer fluid to less than the
minimum working pressure of the potable
water system up to 30 psi maximum. Also,
the heat transfer fluid must be water or
other non-toxic fluid having a toxicity of
Class 1, as listed in Clinical Toxicology of
Commercial Products, 5th Edition.
14. Y-Strainer:
Field supplied. A Y-strainer or equivalent multipurpose
strainer is recommended at the inlet of the heat exchanger
to remove system particles from older hydronic systems and
protect newer systems.

Installation & Operation Manual

Hydronic piping

(continued)

Near boiler piping connections
Figure 6-1A Near Boiler Piping

Figure 6-1B Near Boiler Piping w/Low Loss Header
AIR

AIR
VENT
VENT

VENT

DOMESTIC
HOT WATER
PUMP

OUTLET
INLET
M
FRO

CONDENSATE
DRAIN

BOILER
PUMP

OUTLET
INLET

INDIRECT
DOMESTIC
HOT WATER
TANK
TO

ST
SY

DOMESTIC HOT
WATER PUMP
OM
FR
INDIRECT
DOMESTIC
HOT WATER
TANK
TO

CONDENSATE
DRAIN

SYSTEM
SENSOR
LVE

SYSTEM
PUMP

TO FLOOR
DRAIN

A
AIR
KV
EC
SEPARATOR
CH

AIR VENT
VALVE

SYSTEM
PUMP

BOILER
PUMP

Y-STRAINER
(RECOMMENDED)

OM
FR

ST
SY

AIR
SEPARATOR
EXPANSION TANK

EM
ST
EM
SY
ST
SY
M
O
FR

FILL VALVE
Y-STRAINER
(RECOMMENDED)
EXPANSION TANK

LOW LOSS HEADER
(TYPICAL)

DRAIN (TYPICAL)
DRAIN VALVE

Circulator sizing
The Knight wall mount boiler heat exchanger does have a pressure drop, which must be considered in your system design. Refer
to the graph in FIG. 6-2 for pressure drop through the Knight wall mount boiler heat exchanger.

Installation & Operation Manual

Hydronic piping

Figure 6-2 Pressure Drop vs. Flow
3.00

9.00
8.00

2.50

1.50

1.00

110

4.00

155

2.00
1.00

0.00
-0.50

5.00
3.00

0.50

MODEL

6.00
FT/HD

2.00
FT/HD

7.00

MODEL

0.00

FLOW

3.50
3.00

MODEL

2.00
1.50

199

1.00

285

0.50
0.00

FT/HD

2.50

2.00
1.80
1.60
1.40
1.20
1.00
0.80
0.60
0.40
0.20
0.00

MODEL
399

FLOW

Table 6A Circulator Recommendations for Temperature Rise Applications_20°, 25°, and 35°

20°F Temperature Rise Applications
Model

GPM

FT/HD

Minimum Pipe
Size

55
85
110
155
199
285
399

5
8
10
15
19
27
38

0.27
0.94
1.53
4.26
1.13
2.42
1.42

1"
1"
1"
1"
1.25"
1.25"
1.5"

Grundfos
UPS 15-58FC (1)
UPS 15-58FC (1)
UPS 15-58FC (2)
UPS 15-58FC (3)
UPS26-99F
UPS26-99F
UPS26-99F

Pump
TACO

B&G

Armstrong

NRF-22
NRF-22
NRF-22
NRF-22
NRF-36 (1)
NRF-36 (3)
PL-55

E7
E7
E7
E7
E7
E7
E11

B&G
NRF-22
NRF-22
NRF-22
NRF-36 (1)
NRF-36 (1)
NRF-36 (3)
PL-55

Armstrong
E7
E7
E7
E7
E7
E7
E11

Pump
Minimum Pipe
Model GPM
FT/HD
Size
Grundfos
TACO
B&G
55
3
0.10
1"
UPS 15-58FC (1)
007
NRF-22
85
5
0.37
1"
UPS 15-58FC (1)
007
NRF-22
110
6
0.55
1"
UPS 15-58FC (2)
007
NRF-22
155
9
1.76
1"
UPS 15-58FC (3)
007
NRF-36 (1)
199
11
0.38
1.25"
UPS 15-58FC (3)
0010
NRF-36 (1)
285
16
0.85
1.25"
UPS 15-58FC (3)
0010
NRF-36 (1)
399
22
0.48
1.5"
UPS26-99F
0011
NRF-36 (1)
Pumps listed in bold type are provided by the factory as the boiler circulation pump.
NOTICE

Armstrong
E7
E7
E7
E7
E7
E7
E7

007
007
007
007
0011
0011
0012

25°F Temperature Rise Applications
Model

GPM

FT/HD

Minimum Pipe
Size

55
85
110
155
199
285
399

4
7
8
12
15
22
31

0.17
0.72
0.98
3.13
0.71
1.61
0.95

1"
1"
1"
1"
1.25"
1.25"
1.5"

Pump
Grundfos
UPS 15-58FC (1)
UPS 15-58FC (1)
UPS 15-58FC (2)
UPS 15-58FC (3)
UPS26-99F
UPS26-99F
UPS26-99F

TACO
007
007
007
007
0011
0011
0012

35°F Temperature Rise Applications

NOTICE

The temperature rise provided by a pump/model combination will decrease by 3% per 1000 feet of elevation.

Installation & Operation Manual

Hydronic piping

(continued)

Variable speed pump option
Table 6B Recommended Variable Speed Pumps

VFD PUMP
36.00
33.00
30.00

FT/HD

27.00
24.00

155

21.00

199
285

18.00

399

15.00

UPS26-96FC/VS

12.00

TACO 0013 IFC VS

9.00

UPS26-96 FC/VS 50%

6.00

TACO 0013 IFC VS 50%

3.00
0.00
0

FLOW

Variable speed pumping to maintain a set differential temperature (ΔT) between two (2) sensors allows for the following:
Automatic adjustment of the pump's performance to match the low of the system or zone
Eliminate velocity noise in the zone valve systems
Conserve energy
Since ΔT is directly releated to flow rate, the pump's speed continually adjusts to the required BTU per hour. In almost all
applications the design of the system was based on being able to maintain a certain ΔT and figured by using the universal
hydronics equation of BTU/hr = GPM x 500 x ΔT. Given that, any time there is a change to the heat load (i.e., warmer day
or greater heat loss from a structure) then the GPM should change to match the required BTU/hr. This is achieved when the
variable speed circulators automatically and continually adjust their GPM output (by varying speed) to match the required
BTU/hr output of the system, no matter the changes in heat load, while always maintaining the designed ΔT between a supply
and return sensor.
Variable speed pump setup
Before operation, ensure the following:
- Pump is set for an input signal of 0 - 10Vdc by the dip switches on the pump control
- Pump is set for external signal control (if applicable)
- Pump is set for linear output (if applicable)
- If pump does not come equipped with a 0 - 10 Vdc input option, an optional module
will be required from the vendor
NOTICE

NOTICE

Pump sizing and flow requirements are
based on 20 feet of piping, 4 - 90° elbows,
and 2 - fully ported ball valves.
It is recommended that near boiler
piping systems utilize Primary/Secondary
configurations as shown in FIG.’s 6-3
through 6-9 only. The use of other near
boiler piping configurations could result in
improper building and system flow rates
leading to inadvertent boiler high limit
shutdowns and poor system performance if
proper pump sizing and system flow rates are
not adhered to.

SMART SYSTEM / Multi-temperature loop
control option
The Knight wall mount boiler is capable of producing up
to three (3) set point temperatures to meet different space
heating demands. When using more than one temperature
demand it is necessary to protect the lower temperature
loop from overheating. To help aid with this protection,
Lochinvar offers the Multi- Temperature Loop Control Board
Kit (RLY30086).

Installation & Operation Manual

Hydronic piping

Figure 6-3 Single Boiler - Primary / Secondary Piping

PRESSURE
REDUCING VALVE
PRESSURE
GAUGE

BACKFLOW
PREVENTER

MAKE UP WATER

AIR
SEPARATOR

SYSTEM SUPPLY
SENSOR

MAY SUBSTITUTE LOW LOSS HEADER

TO
SYSTEM
BALL VALVE
(TYPICAL)

FROM
SYSTEM
NOT TO EXCEED 4 PIPE DIA OR MAX. OF 12" APART

SYSTEM
CIRCULATOR

Y-STRAINER
(RECOMMENDED)
FLOW CHECK
VALVE

EXPANSION
TANK

DOMESTIC
HOT WATER
CIRCULATOR

DRAIN POINT
(TYPICAL)

ANTI-SCALD
MIXING VALVE

HOT
WATER
OUT
COLD
WATER
IN

BOILER
CIRCULATOR
PRESSURE
RELIEF
VALVE

BOILER

UNION
(TYPICAL)

DRAIN

INDIRECT
DHW TANK

TEMPERATURE /
PRESSURE
GAUGE

NOTICE

Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.

Installation & Operation Manual

Hydronic piping

(continued)

Figure 6-4 Single Boiler - Single Temperature with Zone Valves - DHW Priority

ZONE #1

PRESSURE
REDUCING VALVE

PRESSURE
GAUGE

ZONE #2

ZONE #3

ZONE #4

BACKFLOW
PREVENTER
ZONE VALVES
(TYPICAL)

MAKE UP
WATER

DIFFERENTIAL
PRESSURE
BYPASS VALVE
(RECOMMENDED)

SYSTEM SUPPLY SENSOR
AIR SEPARATOR

SYSTEM
CIRCULATOR
EXPANSION
TANK

BALL VALVE
(TYPICAL)

MAY SUBSTITUTE LOW LOSS HEADER
NOT TO EXCEED 4 PIPE DIA OR MAX. OF 12" APART

HOT
WATER
OUT

Y-STRAINER
(RECOMMENDED)
FLOW CHECK
VALVE

DRAIN POINT
(TYPICAL)

DOMESTIC
HOT WATER
CIRCULATOR

ANTI-SCALD
MIXING VALVE

COLD
WATER
IN

BOILER
CIRCULATOR
PRESSURE
RELIEF VALVE

BOILER

INDIRECT
DHW TANK

UNION
(TYPICAL)

DRAIN

TEMPERATURE /
PRESSURE
GAUGE

NOTICE

Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.

Installation & Operation Manual

Hydronic piping

Figure 6-5 Single Boiler - Single Temperature Zoned with Circulators - DHW Priority

ZONE #1

PRESSURE
REDUCING VALVE

PRESSURE
GAUGE

ZONE #2

ZONE #3

ZONE #4

BACKFLOW
PREVENTER

FLOW CHECK
VALVE
(TYPICAL)

MAKE UP
WATER
SYSTEM SUPPLY SENSOR
ZONE CIRCULATORS
(TYPICAL)

AIR SEPARATOR

EXPANSION
TANK

BALL VALVE
(TYPICAL)

DRAIN POINT
(TYPICAL)

MAY SUBSTITUTE LOW LOSS HEADER
NOT TO EXCEED 4 PIPE DIA OR MAX. OF 12" APART

Y-STRAINER
(RECOMMENDED)

HOT
WATER
OUT
DOMESTIC
HOT WATER
CIRCULATOR

ANTI-SCALD
MIXING
VALVE

COLD
WATER
IN

BOILER
CIRCULATOR

PRESSURE
RELIEF VALVE

UNION
(TYPICAL)

BOILER

DRAIN
TEMPERATURE /
PRESSURE
GAUGE

NOTICE

INDIRECT
DHW TANK

Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.

Installation & Operation Manual

Hydronic piping

(continued)

Figure 6-6 Multiple Boilers - Single Temperature Zoned with Zone Valves - DHW Priority

Model 2
55
85
110
155
199
285
399

Number of Units
4
5
6
7
Required Pipe Sizes

1-1/4" 1-1/2" 1-1/2" 2"
2"
2"
2"
1-1/4" 1-1/2" 2"
2"
2" 2-1/2" 2-1/2"
1-1/2" 2"
2" 2-1/2" 2-1/2" 2-1/2" 3"
2"
2" 2-1/2" 2-1/2" 3"
3"
4"
2"
2" 2-1/2" 3"
4"
4"
4"
2-1/2" 2-1/2" 3"
4"
4"
4"
5"
2-1/2" 3"
4"
4"
5"
5"
5"

ZONE #1

PRESSURE
REDUCING
VALVE

BACKFLOW
PREVENTER

ZONE #2 ZONE #3 ZONE #4
PRESSURE
GAUGE

BALL VALVE
(TYPICAL)

ZONE VALVES
(TYPICAL)

MAKE UP WATER
DIFFERENTIAL PRESSURE
BYPASS VALVE
(RECOMMENDED)

SYSTEM SUPPLY
SENSOR
AIR SEPARATOR

SYSTEM
CIRCULATOR

EXPANSION
TANK

MAY SUBSTITUTE LOW LOSS HEADER
NOT TO EXCEED 4 PIPE DIA OR MAX. OF 12" APART

DRAIN POINT
(TYPICAL)

ANTI-SCALD
Y-STRAINER
MIXING VALVE
(RECOMMENDED)
(TYPICAL)
DOMESTIC
HOT WATER
CIRCULATOR

BOILER
CIRCULATOR

HOT
WATER
OUT
COLD
WATER
IN

PRESSURE
RELIEF VALVE

BOILER 1
(LEADER)

BOILER 2
(MEMBER 1)

INDIRECT
DHW TANK
TEMPERATURE /
PRESSURE
GAUGE

NOTICE

DRAIN
UNION
(TYPICAL)

Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.

Installation & Operation Manual

Hydronic piping

Figure 6-7 Multiple Boilers - Single Temperature Zoned with Circulators - DHW Priority

Model 2
55
85
110
155
199
285
399

Number of Units
4
5
6
7
Required Pipe Sizes

ZONE #1
PRESSURE
REDUCING VALVE

PRESSURE
GAUGE

BACKFLOW
PREVENTER

ZONE #2 ZONE #3 ZONE #4

MAKE UP
WATER

FLOW CHECK
VALVE
(TYPICAL)

SYSTEM SUPPLY
SENSOR
AIR SEPARATOR

ZONE CIRCULATORS
(TYPICAL)
EXPANSION
TANK

BALL VALVE
(TYPICAL)

MAY SUBSTITUTE LOW LOSS HEADER
NOT TO EXCEED 4 PIPE DIA OR MAX. OF 12" APART

DRAIN POINT
(TYPICAL)

ANTI-SCALD
MIXING VALVE
Y-STRAINER
(RECOMMENDED)
(TYPICAL)
DOMESTIC
HOT WATER
CIRCULATOR

BOILER
CIRCULATOR

HOT
WATER
OUT

PRESSURE
RELIEF VALVE

BOILER 2
(MEMBER 1)
TEMPERATURE /
PRESSURE
GAUGE

NOTICE

COLD
WATER
IN

BOILER 1
(LEADER)

DRAIN
UNION
(TYPICAL)

INDIRECT
DHW TANK

Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.

Installation & Operation Manual

Hydronic piping

(continued)

Figure 6-8 Single Boiler - Multiple Temperature - DHW Priority

PRESSURE
REDUCING VALVE

BACKFLOW
PREVENTER

TEMPERATURE
LOOP #1

TEMPERATURE
LOOP #2

TEMPERATURE
LOOP #3

PRESSURE
GAUGE

MAKE
UP
WATER

MIXING VALVES
(TYPICAL)

SYSTEM
SUPPLY
SENSOR

AIR SEPARATOR

EXPANSION
TANK
WIRES TO
LOOP SENSORS

MAY SUBSTITUTE
LOW LOSS HEADER

BALL VALVE
(TYPICAL)

DRAIN POINT
(TYPICAL)

NOT TO EXCEED 4 PIPE DIA
120VAC TO PUMPS
OR MAX. OF 12" APART
24V SIGNAL TO
Y-STRAINER
MIXING VALVES
(RECOMMENDED)
SHIELDED CABLE TO
BOILER CONTROL
BOILER
CIRCULATOR
DOMESTIC
HOT WATER
FLOW CHECK
CIRCULATOR
VALVE

MULTI-TEMP
LOOP CONTROL

HOT WATER
OUT

ANTI-SCALD
MIXING VALVE

COLD
WATER
IN
PRESSURE
RELIEF
VALVE

BOILER

UNION
(TYPICAL)

DRAIN

TEMPERATURE /
PRESSURE
GAUGE

CAUTION
NOTICE

INDIRECT
DHW TANK

IMG00190

Mixing valves are required for the protection of low temperature loops.
Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.

Installation & Operation Manual

Hydronic piping

Figure 6-9 Multiple Boilers - Multiple Temperature - DHW Piped as a Zone

Model 2
55
85
110
155
199
285
399
PRESSURE
REDUCING VALVE

BACKFLOW
PREVENTER

Number of Units
4
5
6
7
Required Pipe Sizes

TEMPERATURE
LOOP #1

TEMPERATURE
LOOP #2

TEMPERATURE
LOOP #3

WIRES TO
LOOP
SENSORS

PRESSURE
GAUGE

MAKE
UP
WATER

MIXING VALVES
(TYPICAL)
SYSTEM
SUPPLY
SENSOR
AIR SEPARATOR
EXPANSION
TANK
MAY SUBSTITUTE
LOW LOSS HEADER

NOT TO EXCEED 4 PIPE DIA OR MAX. OF 12" APART

BALL VALVE
(TYPICAL)

24V SIGNAL TO
MIXING VALVES
120VAC TO PUMPS
MULTI-TEMP TO
DOMESTIC
LOOP CONTROL
HOT WATER
CIRCULATOR

DRAIN POINT
(TYPICAL)
Y-STRAINER
(RECOMMENDED)

FLOW
CHECK
VALVE

SHIELDED CABLE TO
BOILER CONTROL
HOT WATER
OUT

BOILER
CIRCULATOR

ANTI-SCALD
MIXING VALVE

COLD
WATER
IN

PRESSURE
RELIEF
VALVE

BOILER

DRAIN
UNION
(TYPICAL)

BOILER

TEMPERATURE /
PRESSURE GAUGE

INDIRECT
DHW TANK
IMG00191

CAUTION

Mixing valves are required for the protection of low temperature loops.

NOTICE

Please note that the installer is responsible for ensuring DHW prioritization when piped as a zone.

NOTICE

Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.

Installation & Operation Manual

Hydronic piping

(continued)

Figure 6-10 Single Boiler - Full Flow - Single Temperature - Zoned with Zone Valves - DHW Priority

ZONE #1

PRESSURE
REDUCING VALVE

PRESSURE
GAUGE

ZONE #2

ZONE #3

ZONE #4

BACKFLOW
PREVENTER
ZONE VALVES
(TYPICAL)

MAKE UP
WATER
SYSTEM SUPPLY
SENSOR

DIFFERENTIAL
PRESSURE
BYPASS VALVE
(RECOMMENDED)

AIR SEPARATOR

EXPANSION
TANK

BALL VALVE
(TYPICAL)
DRAIN POINT
(TYPICAL)

Y-STRAINER
(RECOMMENDED)
FLOW CHECK
VALVE

DOMESTIC
HOT WATER
CIRCULATOR

HOT
WATER
OUT

BOILER
CIRCULATOR

ANTI-SCALD
MIXING VALVE

COLD
WATER
IN

PRESSURE
RELIEF VALVE

BOILER

INDIRECT
DHW TANK
UNION
(TYPICAL)

DRAIN

TEMPERATURE /
PRESSURE
GAUGE

NOTICE

It is the responsibility of the installer to ensure that the minimum flow requirements of the boiler are met at
all times during boiler operation. If the minimum flow requirements cannot be met at any time the boiler
must be hydraulically separated from the system.
Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.

Installation & Operation Manual

Hydronic piping

Figure 6-11 Single Boiler - Full Flow - Single Temperature Zoned with Valves - DHW Piped as a Zone

ZONE #1

PRESSURE
REDUCING VALVE

PRESSURE
GAUGE

ZONE #2

ZONE #3

ZONE #4

BACKFLOW
PREVENTER
ZONE VALVES
(TYPICAL)

MAKE UP
WATER
SYSTEM SUPPLY
SENSOR

DIFFERENTIAL
PRESSURE
BYPASS VALVE
(RECOMMENDED)

AIR SEPARATOR

EXPANSION
TANK

BALL VALVE
(TYPICAL)

Y-STRAINER
(RECOMMENDED)

DRAIN POINT
(TYPICAL)

BOILER
CIRCULATOR

HOT
WATER
OUT
ANTI-SCALD
MIXING VALVE

COLD
WATER
IN

PRESSURE
RELIEF VALVE

BOILER

INDIRECT
DHW TANK
UNION
(TYPICAL)

DRAIN

TEMPERATURE /
PRESSURE
GAUGE

NOTICE

Installation & Operation Manual

Hydronic piping

(continued)

Figure 6-12 Single Boiler - Full Flow - Single Temperature Zoned with Circulators - DHW Piped as a Zone

ZONE #1

PRESSURE
REDUCING VALVE

PRESSURE
GAUGE

ZONE #2

ZONE #3

ZONE #4

BACKFLOW
PREVENTER

FLOW CHECK
VALVE
(TYPICAL)

MAKE UP
WATER
SYSTEM SUPPLY SENSOR
ZONE CIRCULATORS
(TYPICAL)

AIR SEPARATOR

EXPANSION
TANK

Y-STRAINER
(RECOMMENDED)
DRAIN POINT
(TYPICAL)

HOT
WATER
OUT

DOMESTIC
HOT WATER
CIRCULATOR
ANTI-SCALD
MIXING VALVE

BALL VALVE
(TYPICAL)

COLD
WATER
IN

PRESSURE
RELIEF VALVE

UNION
(TYPICAL)

BOILER

TEMPERATURE /
PRESSURE
GAUGE

NOTICE

DRAIN

INDIRECT
DHW TANK

Installation & Operation Manual

Gas connections

Connecting gas supply piping
1. Remove the front access panel and refer to FIG. 7-1
to pipe gas to the boiler.
a. Install a field supplied sediment trap / drip leg
upstream of the boiler gas controls.

2. Support piping with hangers, not by the boiler or its
accessories.
 WARNING

Figure 7-1 Gas Supply Piping

The gas valve and blower will not support
the weight of the piping. Do not attempt
to support the weight of the piping with the
boiler or its accessories. Failure to comply
could result in severe personal injury, death,
or substantial property damage.

3. Purge all air from the gas supply piping.
4. Before placing the boiler in operation, check the boiler and
its gas connection for leaks.
a. Close manual main shutoff valve during any
pressure testing at less than 13 inches w.c.
b. Disconnect the boiler and gas valve from the gas
supply piping during any pressure testing greater
than 13 inches w.c.
 WARNING
MANUAL SHUTOFF VALVE
(FIELD SUPPLIED)

GAS SUPPLY

UNION

DRIP LEG

Do not check for gas leaks with an open
flame – use the bubble test. Failure to
use the bubble test or check for gas leaks
can cause severe personal injury, death, or
substantial property damage.

5. Use pipe sealing compound compatible with propane gases.
Apply sparingly only to male threads of the pipe joints so
that pipe dope does not block gas flow.

Installation & Operation Manual

Gas connections

 WARNING

(continued)

Failure to apply pipe sealing compound
as detailed in this manual can result
in severe personal injury, death, or
substantial property damage.

 WARNING Knight wall mount boilers are typically
shipped ready to fire on natural gas.
Check boiler rating plate to determine
which fuel the boiler is set for. If set to
natural gas, it may be converted to LP
by installing an orifice (see page 13).
In order to operate on LP gas, an orifice
MUST BE installed. Failure to comply
could result in severe personal injury,
death, or substantial property damage.
 WARNING

Use two wrenches when tightening gas
piping at boiler (FIG. 7-2), using one
wrench to prevent the boiler gas line
connection from turning. Failure to
support the boiler gas connection pipe
to prevent it from turning could damage
gas line components.

Figure 7-2 Inlet Pipe with Backup Wrench

Natural gas:
Pipe sizing for natural gas
1. Refer to Table 7A for pipe length and diameter. Based on
rated boiler input (divide by 1,000 to obtain cubic feet per
hour).
a. Table 7A is only for natural gas with specific gravity
0.60 inches, with a pressure drop through the gas
piping of 0.5 inches w.c.
b. For additional gas pipe sizing information, refer to
ANSI Z223.1 (or B149.1 for Canadian installations).
Natural gas supply pressure requirements
1. Pressure required at the gas valve inlet pressure port:
• Maximum 14 inches w.c. with no flow (lockup) or with
boiler on.
• Minimum 4 inches w.c. with gas flowing (verify during
boiler startup).
2. Install 100% lockup gas pressure regulator in supply line if
inlet pressure can exceed 14 inches w.c. at any time. Adjust
lockup regulator for 14 inches w.c. maximum.

Propane Gas:
 WARNING Knight wall mount boilers are typically
shipped ready to fire on natural gas. Check
boiler rating plate to determine which fuel the
boiler is set for. If set to natural gas, it may be
converted to LP by installing an orifice (see
page 13). In order to operate on LP gas, an
orifice MUST BE installed. Failure to comply
could result in severe personal injury, death,
or substantial property damage.
Pipe sizing for propane gas

USE BACK UP WRENCH
TO PREVENT PIPE FROM
ROTATING

NOTICE

Maximum inlet gas pressure must not
exceed the value specified. Minimum
value listed is for the purposes of input
adjustment.

1. Contact gas supplier to size pipes, tanks, and 100%
lockup gas pressure regulator.
Propane Supply Pressure Requirements
1. Adjust propane supply regulator provided by the gas
supplier for 14 inches w.c. maximum pressure.
2. Pressure required at gas valve inlet pressure port:
• Maximum 14 inches w.c. with no flow (lockup) or with
boiler on.
• Minimum 8 inches w.c. with gas flowing (verify during
boiler startup).
 WARNING

Ensure that the high gas pressure regulator
is at least 6 - 10 feet upstream of the
appliance.

Installation & Operation Manual

Gas connections

Table 7A Natural Gas Pipe Size Chart

Natural Gas Pipe Capacity Chart
Length of Pipe in Straight Feet for 1/2 PSI

Nominal
Iron Pipe
Size (Inches)
10

100

125

150

175

200

1/2

175

120

N/A

3/4

369

256

205

174

155

141

128

121

113

106

697

477

384

328

292

267

246

236

210

200

179

164

149

138

1-1/4

1400

974

789

677

595

543

502

472

441

410

369

333

308

287

1-1/2

2150

1500

1210

1020

923

830

769

707

666

636

564

513

472

441

4100

2820

2260

1950

1720

1560

1440

1330

1250

1180

1100

974

871

820

2-1/2

6460

4460

3610

3100

2720

2460

2310

2100

2000

1900

1700

1540

1400 1300

11200

7900

6400

5400

4870

4410

4000

3800

3540

3330

3000

2720

2500 2340

23500 16100 13100 11100 10000

9000

8300

7690

7380

6870

6150

5640

5130 4720

 WARNING

Knight wall mount boilers are typically shipped ready to fire on natural gas. Check boiler rating plate to
determine which fuel the boiler is set for. If set to natural gas, it may be converted to LP by installing an
orifice (see page 13). In order to operate on LP gas, an orifice MUST BE installed. Failure to comply could
result in severe personal injury, death, or substantial property damage.

Check inlet gas supply

CSA or UL listed flexible gas connections
are acceptable, but you must exercise
caution to ensure that the line has
adequate capacity to allow your boiler
to fire at full rate. Consult with local
codes for proper installation or service
procedures.
DO NOT adjust gas valve outlet
 WARNING
pressure. The gas valve is factory-set
for the correct outlet pressure. This
setting is suitable for natural gas and
propane, requiring no field adjustment.
Attempting to alter the gas valve outlet
pressure could result in damage to the
valve, causing potential severe personal
injury, death, or substantial property
damage.
The gas piping must be sized for the proper flow and length
of pipe, to avoid excessive pressure drop. Both the gas
meter and the gas regulator must be properly sized for the
total gas load.
If you experience a pressure drop greater than 1 inch w.c.,
the meter, regulator, or gas line is undersized or in need of
service. Perform the steps below when checking inlet gas
supply:
1. Shut off power at source.
2. Shut off gas supply at the manual gas valve in the gas
piping to the appliance.
NOTICE

4.
5.
6.
7.

9.
10.

11.
12.
13.

Loosen the set screw one (1) full turn from inside the
pressure tap on top of the gas valve. Place the tubing of
the manometer over the tap once the set screw is
loosened as shown in FIG. 7-3.
Slowly turn on the gas supply at the field installed
manual gas valve.
Turn on power at source..
Adjust the temperature set point on the control panel of
the SMART SYSTEM control module to call for heat.
Observe the gas supply pressure as the burner fires at
100% of rated input. Percent of burner input will be
displayed on the control panel.
Ensure inlet pressure is within specified range.
Minimum and maximum gas supply pressures are
specified in this section of the manual.
If gas supply pressure is within normal range and no
adjustments are needed, proceed on to Step 11.
If the gas pressure is out of range, contact the gas utility,
gas supplier, qualified installer or service agency to
determine the necessary steps to provide proper gas
pressure to the control.
Shut off power at source.
Shut off the gas supply at the manual gas valve in the gas
piping to the appliance.
Remove the manometer from the pressure tap on top of
the gas valve. Re-tighten the set screw inside the pressure
tap.

Installation & Operation Manual

Gas connections

 WARNING

(continued)

When re-tightening the set screw, be
sure to tighten securely to prevent gas
leaks.
Do not check for gas leaks with an open
flame -- use the bubble test. Failure to
use the bubble test or check for gas leaks
can cause severe personal injury, death,
or substantial property damage.

14. Turn on the gas supply at the manual gas valve.
15. Turn on power at source.
16. Adjust the temperature set point on the control panel
of the SMART SYSTEM control module to the desired
water temperature so the appliance will call for heat.
17. Check burner performance by cycling the system while
you observe burner response. The burner should
ignite promptly. Flame pattern should be stable. Turn
system off and allow burner to cool, then cycle burner
again to ensure proper ignition and flame
characteristics.

Gas Pressure
The gas pressure must remain between 4 inches w.c. (natural),
8 inches w.c. (LP) minimum and 14 inches w.c. (natural and LP)
maximum during stand-by (static) mode and while in operating
(dynamic) mode. If an in-line regulator is used, it must be a
minimum of 10 feet from the Knight wall mount boiler. It is
very important that the gas line is properly purged by the gas
supplier or utility company. Failure to properly purge the
lines or improper line sizing, will result in ignition failure. The
problem is especially noticeable in NEW LP installations and
also in empty tank situations. This can also occur when a utility
company shuts off service to an area to provide maintenance to
their lines.

Gas valve replacement
The gas valve MUST NOT be replaced with a conventional gas
valve under any circumstances. As an additional safety feature,
this gas valve has a flanged connection to the venturi and blower.

 WARNING

Failure to follow all precautions could
result in fire, explosion, or death!

 WARNING

DO NOT adjust gas valve outlet pressure.
The gas valve is factory-set for the correct
outlet pressure. This setting is suitable
for natural gas and propane, requiring
no field adjustment. Attempting to
alter the gas valve outlet pressure could
result in damage to the valve, causing
potential severe personal injury, death, or
substantial property damage.

Figure 7-3 Inlet Gas Supply Check

LOOSEN SET SCREW [1] FULL TURN
THEN PLACE TUBING OVER PRESSURE TAP
IMG00163

DETAIL A

Installation & Operation Manual

Field wiring

 WARNING

NOTICE

ELECTRICAL SHOCK HAZARD – For
your safety, turn off electrical power supply
before making any electrical connections
to avoid possible electric shock hazard.
Failure to do so can cause severe personal
injury or death.
Wiring must be N.E.C. Class 1.
If original wiring as supplied with boiler
must be replaced, use only type 105°C
wire or equivalent.

4. Wire the boiler pump as shown in FIG. 8-2.
5. When connecting a domestic hot water (DHW) pump,
connect the wiring to the line voltage terminal strip as
shown in FIG. 8-2.
6. To activate a system pump, wire as shown in FIG. 8-2. If
the motor is larger than 1/8 hp or 1.8 amps, you must isolate
with a relay.
Figure 8-2 Line Voltage Field Wiring Connections

Boiler must be electrically grounded as
required by National Electrical Code
ANSI/NFPA 70 – latest edition.
 CAUTION

Label all wires prior to disconnection when
servicing controls. Wiring errors can cause
improper and dangerous operation.

Figure 8-1 Remove Bezel

Low voltage connections
1. Route all low voltage wires through the knockouts in the
bottom front right side, just under the control panel, as
shown in FIG. 8-3.

REMOVE BEZEL

Installation must comply with:

2. Connect low voltage wiring to low voltage connection board
as shown in FIG. 8-4 on page 55 of this manual and the
boiler wiring diagram.
Figure 8-3 Routing Field Wiring

1. National Electrical Code and any other national, state,
provincial, or local codes, or regulations.
2. In Canada, CSA C22.1 Canadian Electrical Code Part 1,
and any local codes.

Line voltage connections
1. Remove bezel as shown in FIG. 8-1.
LINE VOLTAGE
JUNCTION BOX

2. Connect 120 vac power wiring to the line voltage terminal
strip in the junction box, as shown in FIG. 8-2.
3. Provide and install a fused disconnect or service switch
(15 amp recommended) as required by the code (see
FIG. 8-2).

LOW VOLTAGE
CONNECTION
BOARD
LOW VOLTAGE
KNOCKOUTS

LINE VOLTAGE
KNOCKOUTS

IMG00164

Installation & Operation Manual

Field wiring

(continued)

Thermostat
1. Connect the room thermostat or end switch (isolated
contact only) to heat/loop demand 1, 2, or 3, as shown
in FIG. 8-4.
2. Install the thermostat on the inside wall away from
influences of drafts, hot or cold water pipes, lighting
fixtures, television, sunlight, or fireplaces.
3. Thermostat anticipator (if applicable):
a. If connected directly to boiler, set for 0.1 amps.
b. If connected to relays or other devices, set to
match total electrical power requirements of
connected devices. See device manufacturers’
specifications and thermostat instructions for
details.

Outdoor temperature sensor
1.

Mount the sensor on an exterior wall, shielded from
direct sunlight or flow of heat or cooling from other
sources.

2. Route sensor wires through a knockout in the bottom
front right side of the boiler (see FIG. 8-3).
3. Connect outdoor temperature sensor (FIG. 8-4) to the
outdoor sensor terminals on the connection board to
enable outdoor reset operation of the Knight wall mount
boiler. If fixed temperature operation is required, do not
install outdoor sensor.

DHW thermostat

1. Connect storage indirect water heater (DHW) thermostat
(FIG. 8-4) to the DHW thermostat terminals on the
connection board. If a tank sensor is connected (see
DHW Tank Sensor below) the tank thermostat is ignored.

DHW tank sensor
1. By installing a tank sensor, the SMART SYSTEM control
can perform the tank thermostat function. The SMART
SYSTEM control automatically detects the presence of
this sensor and generates a DHW call for heat when
the tank temperature drops 6°F (3°C) below the tank
set point and finishes the call for heat when the tank
temperature reaches the tank set point.
2. The tank sensor included with the Lochinvar Squire
Indirect DHW tank (TST20015) is the only sensor
suitable for use with the SMART SYSTEM control.
Connect the sensor leads to the Tank Sensor terminals
on the Low Voltage Connection Board.
 WARNING

Failure to use the correct sensor may
result in the tank temperature being either
above or below the set point.

3. If the TST20015 is not compatible with the indirect tank,
a tank thermostat can be used to control the boiler. The
tank thermostat should be installed per the manufacturers
instructions and wired to the DHW Thermostat terminals
on the Low Voltage Connection Board.

Louver relay
1. If louvers need to operate when the boiler fires, they can
be controlled by this output. Connect these terminals to
a 24 vac relay coil, which is wired to operate the louvers
(FIG. 8-4).

Louver proving switch
1. When the operation of the louvers needs to be verified
before the boiler fires, remove the jumper wire from these
terminals and connect them to the normally open contacts
on its proving switch (FIG. 8-4).

Flow switch
1. A flow switch is used to guarantee flow through the boiler
before allowing it to fire. The flow switch must be installed
at the boiler outlet.
2. Remove the jumper wire from these terminals and connect
these terminals to the normally open contacts on the flow
switch (FIG. 8-4).

Variable speed system pump
If a variable speed pump is used in the primary loop, and a
0-10V signal is available from the pump speed control, this
signal can be used by the SMART SYSTEM control to anticipate
changes in the building heat load. By connecting this 0 - 10V
signal to the 0 - 10V SYS PUMP IN terminals, the boiler (or
cascade) can modulate up and down as the primary flow
increases and decreases.

Boiler pump speed output
This 0 - 10V output is available to control the speed of a variable
speed boiler pump. The SMART SYSTEM control will vary the
speed of this pump in order to maintain a minimum T across
the heat exchanger, as well as prevent high limit lockouts when
the flow in the primary loop is extremely low. Connect this
output to the 0 - 10V input on the boiler pump speed control.

Rate output
This output provides a 0 - 10V signal that is proportional to the
firing rate of the boiler. This may be used by a BMS system to
monitor the actual rate of the boiler.

ModBus
When the optional ModBus interface module is installed, the
RS-485 ModBus cable is connected to these terminals. Use
shielded, 2-wire twisted pair cable. If desired, the shield can
be connected to ground by installing a jumper wire between
terminals 1 and 3 on connector X5 on the optional ModBus
interface module.

Installation & Operation Manual

Field wiring

System supply sensor

Wiring of the cascade

1. By installing the system supply sensor into the supply
of the primary loop, the temperature of the primary
supply can be controlled. The SMART SYSTEM control
automatically detects the presence of this sensor, and
controls the boiler firing rate to maintain the system
supply temperature to the set point (if the outlet sensor
control is currently selected). If it is desired to control
the system return temperature, then program the SMART
SYSTEM control to use the inlet sensor as the controlling
sensor. See the Knight Wall Mount Service Manual for
instructions on how to do this. When the inlet sensor
is programmed as the controlling sensor, it is strongly
recommended that the SYSTEM SUPPLY sensor be
installed. DO NOT INSTALL THE SYSTEM SUPPLY
SENSOR INTO THE SYSTEM RETURN.

When wiring the boilers for Cascade operation, select one boiler
as the Leader boiler. The remaining boilers will be designated
as Members. See page 63 “Configuration of the Cascade” for a
detailed explanation of this procedure.

2. The TST2032 sensor provided with the boiler must be
used for the system sensor.
3. Connect these terminals to the system supply sensor
(FIG. 8-4).

Boiler management system
1. An external control may be connected to control either
the firing rate or the set point of the boiler. If the external
control uses a set of contacts to enable the boiler, connect
the contacts to the Heat/Loop Demand 1 terminals.
Otherwise, the SMART SYSTEM control will be enabled
by the 0-10V signal.
2. Make sure the (-) terminal is connected to the (-) or
common output terminal of the external control, and
the (+) terminal is connected to the 0 - 10 vdc or (+)
terminal of the external control. Make sure the (-)
voltage is not below ground.

Runtime contacts
The SMART SYSTEM control closes a set of dry contacts
whenever the burner is running. This is typically used by
Building Management Systems to verify that the boiler is
responding to a call for heat.

Alarm contacts
The SMART SYSTEM control closes another set of contacts
whenever the boiler is locked out or the power is turned off.
This can be used to turn on an alarm, or signal a Building
Management System that the boiler is down.

Connect the system supply sensor and outdoor air sensor (if
used) to the Leader boiler. For the Cascade system to work
properly the system supply sensor must be installed. The
location of the system supply sensor should be downstream
of the boiler connections in the main system loop (FIG.’s 6-4
and 6-6). The system supply sensor should be wired to the Low
Voltage Connection Board at the terminals marked for the
system sensor (see FIG. 8-4). The Leader control will use the
water temperature at the system supply sensor to control the
operation of the Cascade.
If outdoor air reset is desired, the outdoor air sensor should be
wired to the Low Voltage Connection Board at the terminals
marked for the outdoor air sensor (FIG. 8-4). If the outdoor
air sensor is connected, the Leader control will calculate the
water temperature set point based on the programmed reset
curve parameters. If the outdoor air sensor is not connected,
the Leader control will maintain the fixed water temperature set
point that is programmed into the control.
If a Thermostat, Zone Control enable output, or Building
Management System enable output is available, it should be
wired to the Low Voltage Connection Board on the Leader
boiler at the terminals marked for one of the Heat/Loop
Demands 1-3 (FIG. 8-4). If the boilers are to run continuously,
connect a jumper wire between the R and W terminals for the
Heat/Loop demand input. This will initiate a call for heat on
the Cascade.
Communication between the Leader boiler and the Member
boilers is accomplished by using shielded, 2-wire twisted pair
communication cable. Connect one of the twisted pair wires
to Cascade terminal A on each of the Low Voltage Connection
boards, and the other wire of the twisted pair to Cascade
terminal B on each of the Low Voltage Connection Boards.
Connect the shield wires to one of the shield terminals on the
Low Voltage Connection Boards (FIG. 8-4). If more than two
boilers are on the Cascade, daisy chain the wiring from the
Cascade terminals on the second boiler to the Cascade terminals
on the third boiler, then from the third to the forth, and so on.
The connections between boilers can be made in any order,
regardless of the addresses of the boilers. Try to keep each cable
as short as possible.

COM
NO

HEAT / LOOP
DEMAND 1

HEAT / LOOP
DEMAND 2

HEAT / LOOP
DEMAND 3

TANK THERMOSTAT

FLOW SWITCH

LOUVER
PROVING SWITCH

WIRE AS
NEEDED

BOILER PUMP

SYSTEM PUMP
SPEED CONTROL

BUILDING
MANAGEMENT
SYSTEM

SHIELD

IMG00126

NOTE:
CONNECTION BOARD SPLIT FOR
ILLUSTRATION PURPOSES

SYSTEM SUPPLY SENSOR

OUTDOOR SENSOR

TANK SENSOR

Field wiring

LOUVER RELAY

SHIELD

A TO
B NEXT
BOILER

LOW WATER
CUTOFF

FROM A
PREVIOUS B
BOILER

Installation & Operation Manual

(continued)

Figure 8-4 Low Voltage Field Wiring Connections

Installation & Operation Manual

Condensate disposal

Condensate drain

NOTICE

1. This boiler is a high efficiency appliance that produces
condensate.
2. The bottom of the boiler has a 1 1/4 inch pipe for
connection of the condensate trap (FIG. 9-1).
3. Slope condensate tubing down and away from the boiler
into a drain or condensate neutralizing filter. Condensate
from the Knight wall mount boiler will be slightly acidic
(typically with a pH from 3 to 5). Install a neutralizing
filter if required by local codes.
A Neutralizer Kit is available from the factory (Kit 3087).
4. Do not expose condensate line to freezing temperatures.
5. Use only plastic tubing or piping as a condensate drain
line (FIG. 9-1).

NOTICE

Use materials approved by the authority
having jurisdiction. In the absence of other
authority, PVC and CPVC pipe must comply
with ASTM D1785 or D2845. Cement and
primer must comply with ASME D2564 or
F493. For Canada use CSA or ULC certified
PVC or CPVC pipe, fittings, and cement.
To allow for proper drainage on large
horizontal runs, a second line vent may be
required and tubing size may need to increase
to 1 inch.
The condensate line must remain
unobstructed, allowing free flow of
condensate. If condensate is allowed to
freeze in the line or if the line is obstructed in
any other manner, condensate can exit from
the boiler tee, resulting in potential water
damage to property.

6. A condensate removal pump is required if the boiler is
below the drain. When installing a condensate pump, select
one approved for use with condensing boilers and furnaces.
The pump should have an overflow switch to prevent
property damage from condensate spillage. The switch
should be wired in series with the blocked drain switch
inside the boiler (see FIG. 10-1 on page 58).
Figure 9-1 Condensate Disposal

CONDENSATE
TRAP

CONDENSATE DRAIN CONNECTION ROUTE TO FLOOR DRAIN OR
NEUTRALIZING FILTER USING
3/4" PVC TUBING

REMOVABLE CAP
FOR CLEANING
TRAP
IMG00159

Installation & Operation Manual

Start-up

Check/control water chemistry
Do not use petroleum-based cleaning or
sealing compounds in the boiler system.
Damage to elastomer seals and gaskets
in the system could occur, resulting in
substantial property damage.
Hardness less than 7 grains
 CAUTION

1. Consult local water treatment companies for hard water
areas (above 7 grains hardness).
Chlorine concentration less than 200 ppm
1. Do not fill boiler or operate with water containing
chlorine in excess of 200 ppm.
2. Filling with chlorinated fresh water should be acceptable
since drinking water chlorine levels are much lower.
3. Do not use the boiler to directly heat swimming pool or
spa water.
Test/replace freeze protection fluid
1. For systems using freeze protection fluids, follow fluid
manufacturer’s instructions.
2. Freeze protection fluid must be replaced periodically due
to degradation of inhibitors over time. Follow all fluid
manufacturer’s instructions.

Freeze protection (when used)
1.

Determine freeze protection fluid quantity using
system water content, following fluid manufacturer’s
instructions. Boiler water content is listed on page 6.
Remember to include expansion tank water content.

Local codes may require a backflow preventer or actual
disconnect from city water supply.

When using freeze protection fluid with automatic fill,
install a water meter to monitor water makeup. Freeze
protection fluid may leak before the water begins to
leak, causing concentration to drop, reducing the freeze
protection level.

The freeze protection set points may be lowered when
freeze protection fluid is used (see the Knight Wall
Mount Service Manual).

Fill and test water system

4. At initial fill and during boiler startup and testing, check
system thoroughly for any leaks. Repair all leaks before
proceeding further.
 WARNING Eliminate all system leaks. Continual fresh
makeup water will reduce boiler life. Minerals
can build up in the heat exchanger, reducing
heat transfer, overheating the heat exchanger,
and causing heat exchanger failure.

Purge air from water system
1. Purge air from system:
a. Connect a hose to the purge valve (see purge/drain
valves, in piping diagrams on pages 38 through 47).
Route the hose to an area where water can drain and
be seen.
b. Close the boiler or system isolation valve between
the purge valve and fill connection to the system.
c. Close zone isolation valves.
d. Open quick-fill valve on cold water makeup line.
e. Open purge valve.
f. One zone at a time, open the isolation valves. Allow
water to run through the zone, pushing out the air.
Run until no noticeable air flow is present. Close the
zone isolation valves and proceed with the next zone.
Follow this procedure until all zones are purged.
g. Close the quick-fill water valve and purge valve and
remove the hose. Open all isolation valves. Watch
that system pressure rises to correct cold-fill
pressure.
h. After the system has operated for a while, eliminate
any residual air by using the manual air vents located
throughout the system.
i. If purge valves are not installed in the system, open
the manual air vents in the system one at a time,
beginning with the lowest floor. Close the vent when
water squirts out. Repeat with remaining vents.
2.

Open other vents:
a. Starting on the lowest floor, open air vents one at a
time until water squirts out.
b. Repeat with remaining vents.

3. Refill to correct pressure.

1. Fill system only after ensuring the water meets the
requirements of this manual.
2. Close boiler drain valve and manual air vent.
3. Fill to correct system pressure. Correct pressure will vary
with each application.
a.

The minimum cold water fill pressure for a
residential system is 12 psi.

Pressure will rise when boiler is turned on and
system water temperature increases.

Installation & Operation Manual

Start-up

Check for gas leaks
 WARNING

 WARNING

Before starting the boiler, and during
initial operation, smell near the floor and
around the boiler for gas odorant or any
unusual odor. Remove the front access
panel and smell the interior of the boiler
enclosure. Do not proceed with startup
if there is any indication of a gas leak.
Use an approved leak detection solution.
Repair any leaks at once.
DO NOT adjust gas valve outlet pressure.
The gas valve is factory set for the correct
outlet pressure. This setting is suitable
for natural gas and propane, requiring
no field adjustment. Attempting to
alter the gas valve outlet pressure could
result in damage to the valve, causing
potential severe personal injury, death, or
substantial property damage.
Propane boilers only – Your propane
supplier mixes an odorant with the propane
to make its presence detectable. In some
instances, the odorant can fade, and the
gas may no longer have an odor. Before
startup (and periodically thereafter), have
the propane supplier verify the correct
odorant level in the gas.

Inspect/fill condensate system
Inspect/check condensate lines and fittings
1. Inspect the condensate drain line, condensate fittings and
condensate trap.
2. Fill condensate trap with enough water to make the ball
float (FIG. 10-1).
3. Loosen compression fitting (FIG. 10-1).
4. Slide condensate trap onto condensate drain at the bottom
of the unit.
5. Tighten compression fitting.
 WARNING

The condensate trap (FIG. 10-1) must have
the float ball in place during all times of
boiler operation to avoid flue gas emission
from the condensate drain line. Failure to
ensure the float ball is in place could result in
severe personal injury or death.

Figure 10-1 Condensate Trap
COMPRESSION
FITTING

Check thermostat circuit(s)
1. Disconnect the two external wires connected to each
of the heat/loop demand terminals on the connection
board.

CONDENSATE
DRAIN
FLOAT BALL

2. Connect a voltmeter across these two incoming wires.
Close each thermostat, zone valve, and relay in the
external circuit one at a time and check the voltmeter
reading across the incoming wires.
3. There should NEVER be a voltage reading.
4. If a voltage does occur under any condition, check and
correct the external wiring. (This is a common problem
when using 3-wire zone valves.)
REMOVABLE CAP TO
CLEAN OUT TRAP

5. Once the external thermostat circuit wiring is checked and
corrected if necessary, reconnect the external thermostat
circuit wires to the connection board.

IMG00209

Clean/Inspect Trap Assembly
1. Remove the clean out cap on the bottom of the trap. Let the
condensate and any debris drain out.
2. Refill the trap according to the instructions above.

Installation & Operation Manual

Start-up

(continued)

Final checks before starting the boiler

 Check vent piping and air piping

 Read the Knight Wall Mount Service Manual to
familiarize yourself with SMART SYSTEM control
module operation. Read this manual, pages 60 and 61
for proper steps to start boiler.

1. Check for gas tight seal at every connection, seam of air
piping, and vent piping.
 WARNING

 Verify the boiler and system are full of water and all
system components are correctly set for operation.
 Verify the preparation procedures of Section 10, pages 57
and 58 have been completed.
 Ensure float ball is inside condensate trap (see FIG. 10-1).
 Verify electrical connections are correct and securely
attached.

Venting system must be sealed gas tight
to prevent flue gas spillage and carbon
monoxide emissions, which will result in
severe personal injury or death.

 Check gas piping
1. Check around the boiler for gas odor following the
procedure on page 48 of this manual (connecting gas supply
piping).
 WARNING

 Inspect vent piping and air piping for signs of deterioration
from corrosion, physical damage or sagging. Verify air
piping and vent piping are intact and correctly installed
per this manual.

If you discover evidence of any gas leak,
shut down the boiler at once. Find the
leak source with a bubble test and repair
immediately. Do not start the boiler again
until corrected. Failure to comply could
result in severe personal injury, death, or
substantial property damage.

Start the boiler

 Propane boilers – verify conversion

1. Read and follow the Operating instructions in FIG.’s 10-2
and 10-3 on pages 60 and 61.

1. Verify propane conversion has been completed per the
Propane Conversion instructions.

If boiler does not start correctly

 WARNING

DO NOT adjust gas valve outlet pressure.
The gas valve is factory-set for the correct
outlet pressure. This setting is suitable
for natural gas and propane, requiring
no field adjustment. Attempting to alter
the gas valve outlet pressure could result
in damage to the valve, causing potential
severe personal injury, death, or substantial
property damage.

 WARNING

Knight wall mount boilers are typically
shipped ready to fire on natural gas. Check
boiler rating plate to determine which fuel
the boiler is set for. If set to natural gas,
it may be converted to LP by installing
an orifice (see page 13). In order to
operate on LP gas, an orifice MUST BE
installed. Failure to comply could result in
severe personal injury, death, or substantial
property damage.

1. Check for loose connections, blown fuse or service switch
off?
2. Is boiler water temperature above 200°F?
3. Is thermostat set below room temperature?
4. Is gas turned on at meter or boiler?
5. Is incoming gas pressure less than 4 inches w.c.?
If none of the above corrects the problem, refer to the
Troubleshooting Section of the Knight Wall Mount Service
Manual.

Check system and boiler
 Check water piping
1. Check system piping for leaks. If found, shut down
the boiler and repair immediately. (See WARNINGS
on pages 57 and 58 (startup) regarding failure to repair
leaks.)
2. Vent any remaining air from the system using manual
vents. Air in the system will interfere with circulation
and cause heat distribution problems and noise.

Check flame and combustion
1. Shut off the main power to the boiler by placing the On/Off
switch in the OFF position.
2. Remove the flue temperature sensor from the flue pipe
connection. Note: Combustion measurements will be
made at this point.
3. Turn on the main power to the boiler by placing the On/Off
switch in the ON position.

Installation & Operation Manual

Start-up

Figure 10-2 Operating Instructions - Models 55 - 285

Installation & Operation Manual

Start-up

(continued)

Figure 10-3 Operating Instructions - Model 399

Installation & Operation Manual

Start-up

Check flame and combustion (continued)
NOTICE

Please note that the brackets ([]) denote
screen status.

4. Place the boiler into the active position by pressing the
RIGHT SELECT [ON] key (FIG. 11-1, page 70).
5. Locate the pinhole button below the RESET button on
the display board (FIG. 11-1). Insert a thin wire (such as
a paper clip) into the hole and press the button once and
hold for 5 seconds to place the boiler into Service Mode.
In Service Mode the boiler will fire at ignition speed and
will then modulate up to full fire.
6. Insert the probe from a combustion analyzer into the hole
left by the removal of the flue temperature sensor.
7. Once the boiler has modulated up to full fire, measure
the combustion. The values should be in the range listed
in Table 10A below. The CO levels should be less than
150 ppm for a properly installed unit.
If the combustion is not within the specified range,
reference the Troubleshooting Section of the Knight Wall
Mount Service Manual for possible causes and corrective
actions.
Table 10A Flue Products Chart
Natural Gas

Set space heating operation
Determine controlling sensor
For space heating systems, the temperature control can be
based on one of three sensors; the inlet, outlet, or system
supply sensor. The SMART SYSTEM control is programmed at
the factory to control the temperature of the outlet sensor. The
control will automatically switch to the system supply sensor
once it is connected. If it is desired to base the temperature
control on the inlet sensor, the appropriate parameter must
be changed in the control. See the Knight Wall Mount Service
Manual for a detailed explanation of this procedure.
Verify space heat circulator mode
The Space Heating Mode controls both the system pump (if
connected), and the boiler pump. When the SMART SYSTEM
control receives a space heating call for heat, it turns on the
system pump. If the boiler is not heating an indirect DHW
(Domestic Hot Water) tank, and the set point is not met, it
also turns on the boiler pump. After the space heating call
for heat ends, the system pump continues to run for a short
period of time. The system pump can be programmed to run
continuously, except during outdoor shutdown. If the boiler
pump was running, it continues to run for a short period of
time as well. These pump delays are factory set to 30 seconds.
If different delays are desired, the appropriate parameters in
the control must be changed. See the Knight Wall Mount
Service Manual for a detailed explanation of this procedure.

Propane

CO2

8.0% - 10%

3.0% - 6.5%

10.0% - 11%

4.1% - 5.4%

Adjust set point temperature(s)
NOTICE

Please note that the brackets ([]) denote
screen status.

Once the combustion analysis is complete, test the
safety shutoff device by turning the manual shutoff
switch to the OFF position and ensuring that the boiler
shuts down and registers an alarm. Turn the manual
shutoff switch to the ON position and reset the control.

The NAVIGATION dial may be used during normal operation
to adjust the space heating and tank set point temperatures.

Turn off power at source and replace the flue temperature
sensor into the flue pipe connection.

3.
4.

10. Place the boiler back into normal operation.
You must replace the flue gas temperature
 WARNING
sensor to prevent flue gas spillage into
the room. Failure to comply could
result in severe personal injury, death, or
substantial property damage.

1.
2.

5.
6.
7.

From the Status Screen press the NAVIGATION dial.
Turn the NAVIGATION dial counterclockwise to select the
appropriate set point.
Press the NAVIGATION dial to adjust the temperature.
Once the desired temperature is displayed, press the
RIGHT SELECT [SAVE] key.
If necessary repeat Steps 3 and 4 to make adjustments to
additional set points.
Press the RIGHT SELECT [HOME] key to upload the
changes.
If the RIGHT SELECT [SAVE] key is not pressed, the
new settings will be discarded.

Installation & Operation Manual

Start-up

(continued)

Set domestic hot water (DHW) operation
Verify DHW mode
There are two (2) modes of operation for DHW. In Normal
Mode, when a DHW demand begins, the control will start
the DHW pump, turn off the boiler pump (if running), and
modulate to bring the outlet temperature to the DHW boiler
set point. The maximum firing rate may be limited in this
mode if desired.

Turn the NAVIGATION dial to adjust the minutes. Press
the NAVIGATION dial.

Turn the NAVIGATION dial to adjust the month. Press the
NAVIGATION dial.

Turn the NAVIGATION dial to adjust the date. Press the
NAVIGATION dial.

In Zone Mode it is assumed that the indirect DHW tank is
piped as a zone on the primary loop. When a DHW demand
begins, the control will turn on the DHW pump output, and
raise the system temperature set point to the DHW boiler set
point (if higher). The boiler pump will be turned on. The
system pump may be forced on, forced off, or not changed,
depending on the System Pump Mode selected (reference
the Knight Wall Mount Service Manual for details). In this
mode, any low temperature zones (such as radiant heating)
may need additional controls to limit the water temperature
sent to those zones.

The clock is automatically updated whenever a PC is connected
and the Win_Pro-Installer program is started.

Set DHW boiler target temperature

Configuration of the cascade

When in the DHW Mode, the control will modulate to
maintain the boiler outlet temperature or system supply
temperature to a set point. This set point is set at the factory
to 180°F. If a different set point is desired, the appropriate
parameter in the control must be changed. See the Knight
Wall Mount Service Manual for a detailed explanation of this
procedure.
Set maximum DHW fan speed
If the rated input of the indirect tank is less than the maximum
output of the boiler, change the maximum DHW fan speed
setting to limit the boiler output accordingly, see the Knight
Wall Mount Service Manual for a detailed explanation of this
procedure.
Set clock
NOTICE

Please note that the brackets ([]) denote
screen status.

The SMART SYSTEM control has a built-in clock that it
uses for its night setback feature and for logging events. This
clock must be set when the boiler is installed, and anytime the
boiler has been powered off for more than 4 hours. Use the
following procedure to set the clock:
1.
2.
3.
4.
5.
6.

Press and hold the LEFT SELECT [MENU] key for at
least 5 seconds.
The display changes to read [PASSWORD],
with four (4) zeros below it.
Press the RIGHT SELECT [SAVE] key.
The display will then show a menu with the time and
date and temperature unit.
Press the NAVIGATION dial twice.
Turn the NAVIGATION dial to adjust the hours. Press
the NAVIGATION dial.

10. Turn the NAVIGATION dial to adjust the year. Press the
RIGHT SELECT [SAVE] key.
11. Press the RIGHT SELECT [HOME] key.

NOTICE

The internal clock does not adjust for
Daylight Savings Time and therefore, will
require a manual adjustment.

Please note that the brackets ([]) denote
screen status.

When installed in a Cascade system, the individual controls must
be programmed for cascade operation. This is accomplished by
accessing the control parameters.
Press the [MENU] key for at least five (5) seconds. Input the
Installer code as described in the Knight Wall Mount Service
Manual. Once the control parameters have been accessed, use
the NAVIGATION dial to select the Control Mode parameters.
Press the NAVIGATION dial to access these parameters.
Rotate the NAVIGATION dial to select the parameter Cascade
Address. Press the NAVIGATION dial to access this parameter.
Each appliance in the Cascade system must be programmed
with its own address. The boiler designated as the Leader will
have an address of 0. The remaining boilers in the Cascade
will be Members and have addresses from 1 - 7. Rotate the
NAVIGATION dial to select the appropriate address. Press the
RIGHT SELECT [SAVE] key.
Press the RIGHT SELECT [HOME] key to upload the address
into the control. Repeat this procedure for all boilers in the
Cascade, designating the Leader control and the Member
controls.

Installation & Operation Manual

Operating information

General

How the boiler operates
The Knight wall mount boiler uses an advanced stainless
steel heat exchanger and electronic control module that
allows fully condensing operation. The blower pulls in air
and pushes flue products out of the boiler through the heat
exchanger and flue piping. The control module regulates
blower speed to control the boiler firing rate. The gas valve
senses the amount of air flowing into the boiler and allows
only the right amount of gas to flow.

How the control module operates
The SMART SYSTEM control module receives inputs
from boiler sensors and external devices. The control
module activates and controls the blower and gas valve to
regulate heat input and switches the boiler, Domestic Hot
Water (DHW), and system pumps on and off as needed.
The user programs the module to meet system needs by
adjusting control parameters. These parameters set operating
temperatures and boiler operating modes. Boiler operation
can be based on boiler outlet water temperature, boiler inlet
water temperature, system temperature, a 0 - 10V signal, or
Modbus, depending on the parameter settings.

Control inputs and outputs
Space heating demands
There are three (3) heat/loop demand connections available
on this control. These inputs tell the boiler to provide water
for space heating. Each demand connection has its own set
point and outdoor air reset curve. When multiple demands
have a call for heat the control will give priority to the
demand with the highest set point.
Example: Assume that both Heat/Loop Demand 1 and Heat/
Loop Demand 2 have a call for heat. Heat/Loop Demand 1
has a set point of 110°F. Heat/Loop Demand 2 has a set point
of 140°F. The boiler will regulate the system temperature to
140°F until Heat/Loop Demand 2 has been satisfied. Once
Heat/Loop Demand 2 has been satisfied the boiler will
provide 110°F water to the system.
When multiple temperature loops are
 CAUTION
used, thermostatic mixing valves are
required for the protection of any low
temperature loops.
0 - 10V input (set point or power)
The Knight wall mount boiler can be controlled by a Building
Management System (BMS) using a 0 - 10 vdc signal. The
control can be configured by the installer to use this signal to
either control set point or firing rate.
SMART SYSTEM Multi-temp loop control
The Knight wall mount boiler is capable of producing up
to three (3) set point temperatures to meet different space
heating demands. This device controls the temperatures
of up to three (3) separate loops, based on the settings for
the three (3) heat/loop demands (reference Lochinvar kit
RLY30086).

The Knight wall mount boiler can also be programmed to
accept a call for heat from a 0 - 10V signal, reference the Knight
Wall Mount Service Manual for a detailed explanation of this
procedure.
DHW priority
The SMART SYSTEM control allows the connection of a DHW
thermostat or tank sensor to the low voltage connection board.
When a tank sensor is connected, the DHW thermostat input
is ignored. When a boiler is programmed for DHW Normal
Mode, the maximum firing rate can be limited to match the
input rating of the indirect tank coil.
DHW / space heating (SH) cycling
If a DHW call for heat is received while a space heating call is
in progress, and the DHW is in Normal Mode, the control will
start the DHW pump and shut the boiler pump off. The system
pump will remain on. For stand-alone boilers, if the space
heating call is still active while the DHW call is in operation, the
control will wait for 30 minutes (time adjustable by installer)
then it will switch back to the space heating demand. There is
a timer to switch from space heating to DHW and a timer to
switch from DHW to space heating. The control will switch
back and forth until one of the heat demands end.
Programmable controlling sensor
The control module is programmed to use the outlet sensor
as the control sensor by default. If a system supply sensor
is connected, the control automatically uses it as the control
sensor. The control sensor can be changed by the installer to
the inlet sensor. If the inlet sensor is chosen as the controlling
sensor, it is recommended that the system supply sensor
be installed in order to provide the best control of the inlet
temperature.
Anti-cycling
After the burner turns off, the control will delay the next burner
cycle for a set time period (time is adjustable by the installer).
The time delay will be bypassed if the inlet water temperature
drops too far during the delay.
Boiler and system pump control
The boiler pump will run whenever the burner is firing, unless
the DHW is programmed for Normal Mode and the boiler is
heating the DHW tank. The boiler pump will run during Freeze
Protection Mode as well. It will continue to run for a short time
after the burner turns off or the Freeze Protection Mode ends.
The system pump will run whenever there is a space heating call
for heat, or the boiler goes into Freeze Protection Mode. It may
be programmed to run during a DHW call for heat when the
DHW is programmed for Zone Mode. It will continue to run
for a short time after the end of the heat demand or the Freeze
Protection Mode. The system pump can be programmed to run
continuously if desired, except during outdoor shutdown and/
or a DHW call for heat.

Temperature control
Modulation
The Knight wall mount boiler is capable of modulating its firing
rate from a minimum of 20% to a maximum of 100%. The
firing rate is dictated by the call for heat (i.e., space heating or
domestic hot water), the heating load, ramp delay (if enabled),
and various other temperature limitations.

Installation & Operation Manual

Operating information

(continued)

Ramp delay

Protection features

For systems with lower flow, the SMART SYSTEM can limit
the firing rate (when enabled) when a space heating call for
heat starts, or when switching from a DHW call for heat to a
space heating call for heat. There are six (6) limits that can be
programmed, as well as six (6) time intervals corresponding
to each limit. The sixth limit will also limit the firing rate for
the rest of the call for heat.

Outlet temperature, flue temperature, and temperature
rise limiting
The outlet temperature is monitored by the boiler outlet
temperature sensor. When the outlet temperature exceeds
185°F, the unit will reduce the fan speed. If the outlet water
temperature exceeds 195°F the control will shut the unit down
until it cools off.

Gradient limiting

Outdoor air reset

The control module monitors the flue temperature by a sensor
located in the flue exhaust. If the flue temperature exceeds
215°F the control will reduce the maximum fan speed. If
the flue temperature exceeds 240°F the control will shut the
unit down. The unit will restart automatically once the flue
temperature drops 25°F and the minimum off time has expired.

With the outdoor air sensor connected, the control module
will calculate the set points of the three (3) space heating
demands based on the programmed reset curves. The
installer can change the slope of the reset curves by several
adjustable parameters. The user can limit the maximum set
point for the system using the space heating set points.

The control monitors the temperature difference between the
inlet and the outlet sensor. If this difference exceeds 55°F the
control will reduce the maximum fan speed. If the temperature
difference exceeds 60°F the control will shut the unit down. The
unit will restart automatically once the temperature difference
has dropped below 55°F and the minimum off time has expired.

Boost function

Freeze protection

If outdoor air reset is active, and any space heating demand
has been active continuously for a set period of time (time
adjustable by installer) and there has been no DHW demands,
the control will increase the set point of that demand by a
fixed number of degrees (adjustable by installer). This process
will continue until the space heating demand ends, the set
point reaches the programmed set point or a maximum of
20 increases has occurred. Once the system heat demand is
satisfied, the set point will revert to the value determined by
the reset curve.

DO NOT install the boiler in a room likely to freeze.

If during operation of the boiler the outlet water temperature
is rising too quickly, the control will reduce the firing rate to
its lowest setting.

Night setback
The controller may be programmed to reduce the space
heating and DHW set points during certain times each week.
Seven different start and stop times may be programmed for
the space heating setback and seven start and stop times for
the DHW setback. Any night setback scheduled within the
next seven (7) days can be temporarily bypassed if desired.

The following integral feature of the SMART SYSTEM control
module provides some protection for the boiler only -- not for
the system.
•

•
•
•
•

The SMART SYSTEM control module provides
freeze-up protection as follows when the boiler
water temperature drops below 45°F:
Below 45°F, the boiler and system pumps operate
constantly.
Below 37°F, the boiler turns on and runs at 20% of rate.
Boiler and pumps turn off if boiler water
temperature rises above 45°F.
Lower temperatures may be programmed for
systems with anti-freeze solutions (see the Knight Wall
Mount Service Manual.

NOTICE

Flame current support
To prevent nuisance shutdowns when the boiler is firing at
minimum rates, the control will increase the firing rate when
the flame signal drops too low.

 CAUTION

When system return temperatures
are maintained below the dew point,
condensation will form on the inside of the
boiler jacket causing some internal sheet
metal components to rust.
This feature of the SMART SYSTEM control
module does not eliminate the possibility
of freezing. The installation must still
use recognized design, installation and
maintenance practice to prevent freeze
potential for the boiler and system.

Installation & Operation Manual

Operating information

Monitor external limits

High limit operations

Connections are provided on the connection board for
external limits such as flow switch, low water cutoff, gas
pressure switches, and a louver proving switch. The SMART
SYSTEM will shut off the burner and inhibit relighting
whenever any of these external limits open.

The Knight wall mount is equipped with adjustable automatic
reset and manual reset high limits. The automatic reset high
limit has a maximum set point of 200°F and the manual reset
high limit has a maximum set point of 210°F.
When the outlet temperature exceeds 200°F, the automatic
high limit action occurs. The boiler shuts down until the outlet
water temperature cools below 190°F, and a 60 second timer
has expired. If the outlet temperature continues to increase, the
manual reset high limit action will occur at 210°F.

Run-time and alarm outputs
The boiler provides dry contacts for indicating when the
boiler is running, and when it is unable to operate.
Run-time and cycle counting
The control uses two timers to monitor the total hours of
burner operation. One timer monitors the time the boiler is
firing in the Space Heating Mode. The other timer monitors
the time the boiler is in the DHW Mode.

High limit test procedure
NOTICE
1.
2.

The control uses two (2) ignition counters to monitor the
amount of boiler cycles. The first counter counts all ignitions
of the control. The second counter counts only ignition
attempts that have failed.

3.
4.

Service reminder

The control can be programmed for service reminder
notification. This notification will become active when either
a set time frame has expired, or a set amount of running
hours or cycles has expired (all adjustable by the installer).
The display will show a Maintenance Required screen. The
installer's name and phone number can be programmed into
the control. This information will appear on the Maintenance
Required screen. The service reminder notification can be
reset or disabled by the installer.

6.
7.
8.

Error logging
The control will hold in memory the last 10 lockouts as
well as the last 10 blockings. The date and time of the
occurrence will be recorded as well. Only the 10 most current
occurrences of each will be held in memory.

Boiler temperature regulation

10.

Operating temperature (target)
The SMART SYSTEM control module senses water
temperature and regulates boiler firing and firing rate to
achieve a target temperature. The target temperature can be
set between 32°F and 190°F.
•

Target temperature is fixed when the outdoor
sensor is not installed.

•

Target temperature is calculated as described in
this section under “Outdoor Reset Operation” and
“Target Temperature Boost” when the outdoor
sensor is connected.

11.
12.
13.
14.
15.

Please note that the brackets ([]) denote
screen status.

Turn ON the main power to the boiler by placing the
ON/OFF switch in the ON position.
From the Status Screen, press the NAVIGATION dial to
access the Set Points Screen.
Press the LEFT SELECT (LIMITS) key.
Select the manual reset high limit (MRHL) by rotating
the NAVIGATION dial counterclockwise, then press
the NAVIGATION dial.
Decrease the set point of the MRHL to below the current
outlet temperature (or to its minimum setting, whichever
is higher) by turning the NAVIGATION dial
counterclockwise.
Press the RIGHT SELECT [SAVE] key.
Press the RIGHT SELECT [HOME] key. The new
parameter will upload to the control.
If the current outlet temperature is above the new MRHL
set point, the MRHL will function causing boiler lockout.
If this occurs, skip to Step 11.
If the current outlet temperature is below the new MRHL
set point, locate the pinhole (SERVICE button) below the
RESET button on the display board. Insert a thin probe
(such as a paper clip) into the hole and press the button
continuously for five (5) seconds to place the boiler into
Service Mode. In Service Mode, the boiler will fire at
ignition speed and will then modulate up to full fire.
Once the outlet temperature rises up to the MRHL set
point, the MRHL will function, causing the boiler to shut
down and lock out.
Repeat Steps 2, 3 and 4.
Set the MRHL to the appropriate set point by turning the
NAVIGATION dial clockwise.
Repeat Steps 6 and 7.
Press the RESET button to clear the lockout.
If needed, press the RIGHT SELECT [STOP] key to exit
Service Mode.

Installation & Operation Manual

Operating information

Low water cutoff protection
1. The SMART SYSTEM control module uses temperature
sensing of both supply and return areas of the heat
exchanger. If the flow rate is too low or the outlet
temperature too high, the control module modulates and
shuts the boiler down. This ensures boiler shutdown in
the event of low water or low flow conditions.
2. Some codes and jurisdiction may accept these integral
features of the control in lieu of requiring an additional
limit control or low water cutoff. Consult local
jurisdiction to determine. A low water cutoff is available
from the factory (WTR20009).

Outdoor reset operation, if used
Target temperature with outdoor reset
This feature improves the system’s efficiency as the outdoor
temperature warms up.
See the Knight Wall Mount Service Manual to change the
settings.
Reset curve
The reset curve looks at outdoor air temperature and adjusts
the set point.

Cascade
When multiple boilers are installed, they can be wired
together in a cascade sequence. A maximum of eight boilers
can be controlled from a single control. In this application
one boiler would be designated as the Leader control and all
others would be designated as Member controls. The Leader
control can be programmed to use Lead/Lag or Efficiency
Optimization control methods.
Once the Leader boiler receives a call for heat from a room
thermostat, BMS, or Modbus, the control will determine what
the set point will be. If outdoor air reset is desired, connect
the outdoor air sensor to the terminals on the Low Voltage
Connection Board on the Leader boiler. The set point will be
calculated based on the programmed reset curve parameters.
See the Knight Wall Mount Service Manual to program the
reset curve. If outdoor air reset is not desired, do not connect
the outdoor air sensor. A fixed temperature set point can be
programmed into the control. See page 62 of this manual to
program the set point.
If the water temperature at the system supply sensor is
less than the set point + the turn-off offset - the off-on
differential, then the control will initiate a call for heat on
the Cascade (see the Knight Wall Mount Service Manual for
an explanation of the offset and differential). The Leader will
energize the lead boiler on the Cascade. For a new startup this
will be the Leader boiler.

(continued)

Sequence of the cascade
To equalize the run time of all boilers on the Cascade, the firing
sequence will automatically be changed at set intervals. The
sequence will change every hour during the first 24 hours, after
that the sequence will be changed once every 24 hours. The
switching on/off sequence will be as follows:
TIME

SWITCHING ON SEQUENCE

Start

L-M1-M2-M3-M4-M5-M6-M7

1 hour

M1-M2-M3-M4-M5-M6-M7-L

2 hours

M2-M3-M4-M5-M6-M7-L-M1

If a boiler is used to heat an indirect DHW tank, or locks out,
it will automatically be given the lowest priority for the rest of
that 24 hour period.
DHW, Night Setback, and Ramp Delay operation with
cascade
For Normal Mode DHW operation any boiler(s) in the Cascade
can be selected to provide heat for a DHW call. Select a boiler
to be designated as the DHW boiler. Connect the DHW
thermostat or sensor to the terminals on the Low Voltage
Connection Board marked for the corresponding device. When
the boiler receives a DHW call, the Leader control will take that
boiler out of the Cascade sequence. If another boiler is available,
the Leader will start it up to take its place.
The DHW boiler will adjust its set point to the programmed
DHW boiler set point and will adjust its firing rate to maintain
this. Once the DHW call has been satisfied, the Leader control
will place that boiler back into the Cascade sequence.
Switching of the boiler between DHW operation and SH
operation when there is a call for both does not occur in
Cascade Mode.
When DHW is programmed for Zone Mode, connect the DHW
thermostat or tank sensor to the Leader boiler. When a DHW
call is received, the Leader will modulate the entire Cascade to
bring the system supply temperature up to the DHW boiler set
point.
Night Setback operation of the boilers within the Cascade is
available. Programming of the Night Setback will be done
through the Leader boiler. Refer to the Knight Wall Mount
Service manual for information regarding Night Setback.
Ramp Delay operation of the boilers as described in the Knight
Wall Mount Service Manual is not active when the boilers are
part of a Cascade system.

Installation & Operation Manual

Operating information

Sequence of operation
OPERATION

1. Upon a call for heat, the gas pressure switch(es) must be closed.

2. Once the gas pressure switch(es) are closed, the control turns
on the appropriate pumps (system and boiler pumps for space
heating, DHW pump for DHW). The flow switch and/or LWCO
must close.

3. The control turns on power to the louver relay. The louver
proving switch, air pressure switch, and blocked drain switch
must close.

4. The control starts the prepurge cycle by initiating the blower.

5. The control starts the trial for ignition by firing the spark
electrode and opening the gas valve.

6. If flame is not detected after the sparking ends, the control will
perform a postpurge, then start another prepurge cycle and try to
light the burner again. The control will perform a total of 4
attempts before locking out.

7. If flame is detected, it holds the firing rate steady for a few
seconds to let the flame stabilize, then it begins to modulate the
firing rate based on a set point or some other command (such
as a 0-10V BMS signal).

DISPLAY

Installation & Operation Manual

Operating information

(continued)

OPERATION

DISPLAY

8. If the space heating call for heat is active, and the tank thermostat
or sensor starts a DHW call for heat, the boiler will switch to the
DHW mode. If programmed for normal DHW operation (not as a
zone), the DHW pump will turn on first, then the boiler pump will
turn off (boiler and DHW pump operation briefly overlap to ensure
flow is maintained through the unit). This will divert the boiler’s
outlet water from the heating system and send it to the tank coil
instead. The control will then modulate to maintain the outlet
temperature to the DHW boiler set point.
9. If the boiler is not part of a Cascade, and both the space heating
and DHW calls for heat remain active long enough, the boiler will
switch back and forth between the two heating modes until one of
them is satisfied.

10. Once both calls for heat are satisfied, the control will turn off
the burner. The blower will continue to run during the postpurge
period.

11. Any pumps that are running will continue to run for their respective
pump delay times before turning off, unless programmed to
remain on continuously. A 60 second anti-cycle period will start,
which will delay any new call for heat until it times out.

12. In Standby, ready to start a new cycle.

Access modes
User

Saving parameters (reference the Parameter Table in
the Knight Wall Mount Service Manual)
NOTICE

Please note that the brackets ([]) denote
screen status.

The user can adjust space heating and tank target temperatures
by pressing the NAVIGATION dial when “SETPOINTS” is
flashing at the bottom of the display. The date and time, and
the temperature units can also be changed (see page 63).

To save parameters and exit programming:

Installer

Press the RIGHT SELECT [SAVE] key and then press the
RIGHT SELECT [HOME] key.

Most parameters are available only to the installer, accessible
by entering the installer password, see the Knight Wall Mount
Service Manual.

To enter a parameter and continue programming:
Press the RIGHT SELECT [SAVE] key 1 time to return to the
parameter listings; press again to return to the menu listings.
Remember to press the RIGHT SELECT [HOME] key when
finished programming in order to save the changes made.
See the Knight Wall Mount Service Manual for a detailed
description of parameters and access modes.

Installation & Operation Manual

Operating information

Knight wall mount boiler control module

Use the control panel (FIG. 11-1) to set temperatures, operating conditions, and monitor boiler operation.
Figure 11-1 Control Panel

NAVIGATION DIAL

The information on the bottom of the display shows the functions of the two SELECT keys (on either corner), and the
NAVIGATION dial (in the center):
MENU = Left SELECT Key
SETPOINTS = NAVIGATION Dial - Pressing Down
SHDN = Right SELECT Key

Installation & Operation Manual

Operating information

(continued)

Figure 11-2 Status Display Screen

(BOILER
STATUS)

(CALL FOR
HEAT)

C
(OPERATIONAL
INFORMATION)

(RIGHT SELECT KEY)

(LEFT SELECT
KEY)

E
(NAVIGATION DIAL)

Status Display Screens
Section

A
(Boiler Status
Bar)

Display

Description

STANDBY

The unit has not received a call for heat from a remote thermostat nor
has it received a call for heat from a DHW thermostat.

START

The unit has begun a burn cycle and is checking all safety circuits.

PREPURGE

The unit has initiated a prepurge period on a call for heat.

IGNITION

The unit has begun a spark period to ignite the main burner.

The unit has fired and is running at the displayed percentage.

POSTPURGE

The call for heat has been satisfied and the unit runs the fan for an
additional postpurge period to clear the combustion chamber and
vent system of residual flue products.

SHUTDOWN

The unit has been placed in the OFF position.

SETPOINT MET

The controlled temperature has exceeded its set point and its offset.

BLOCKED

The unit has detected a condition that has temporarily interrupted
the current call for heat.
Heat/Loop Demand 1 has a call for heat.
Heat/Loop Demand 2 has a call for heat.

B
(Call for Heat
Indicators)

Heat/Loop Demand 3 has a call for heat.
The tank thermostat or sensor has a call for heat.
Indicates which heat/loop demand shows priority.
The unit is being controlled by a 0 - 10V BMS signal.
The member unit is supplying heat while in Cascade Mode.

Installation & Operation Manual

Operating information
Status Display Screens (cont’d)
Display

Section

C
(Operational
Information)

Description

SYSTEM:

The temperature read by the system supply sensor (if connected).

TANK:

The temperature read by the tank sensor (if connected).

OUTDOOR:

The temperature read by the outdoor sensor (if connected).

INLET TEMP:

The temperature read at the inlet to the heat exchanger.

OUTLET TEMP:

The temperature read at the outlet of the heat exchanger.

DELTA T:

The temperature difference between the inlet and the outlet of the
heat exchanger.

FLUE TEMP:

The temperature read by the flue sensor.

FLAME CURRENT:

The current measured by the flame sense circuit.

FAN SPEED:

The speed of the combustion blower.

BOILER PUMP:

The status of the boiler pump output.

SYSTEM PUMP:

The status of the system pump output.

DHW PUMP:

The status of the DHW pump output.

BMS VOLTAGE:

The voltage received from a BMS system.

BLR PUMP OUTPUT:

The speed signal sent to a variable speed boiler pump in percent.

SYS PUMP INPUT:

The speed signal received from a variable speed system pump control.

RATE OUTPUT:

A 0 - 10V signal indicating the firing rate of the boiler.

SH RUN HOURS:

The total hours of operation in the Space Heating Mode.

SH CYCLES:

The total burner cycles in the Space Heating Mode.

DHW RUN HOURS:

The total hours of operation in the DHW Mode.

DHW CYCLES:

The total burner cycles in the DHW Mode.

LAST 10 FAULTS NO:*

The last 10 lockouts.

NIGHT SETBACK

Shows the next Night Setback trigger (if active).

Installation & Operation Manual

Operating information

Status Display Screens (cont’d)
Display
Description

Section

D
(LEFT SELECT
key function)

(continued)

Press and hold the LEFT SELECT key for 5 seconds to enter the Menu
Screen.

EXIT

Press the LEFT SELECT key to exit the current screen or setting.

YES

Press the LEFT SELECT key to confirm that the boiler needs to
shutdown.

LIMITS

Press the LEFT SELECT key to enter the screen that allows you to
adjust the limit settings.

HOME

Press the LEFT SELECT key to return to the Status Screen and upload
parameter changes.

SKIP

Press the LEFT SELECT key when in the Night Setback Screen to
access the Night Setback Skip Screen.
Turning the NAVIGATION dial will select the next or previous Status
Screen.
Pressing the NAVIGATION dial will show the next fault, NSB (Night
Setback) trigger, or ramp delay setting.
Pressing the NAVIGATION dial will select the setting indicated by
the cursor.

E
(NAVIGATION
Dial Function)

Pressing the NAVIGATION dial will display the Set Points Screen.
Turning the NAVIGATION dial will move the cursor up or down.
Turning the NAVIGATION dial will increase or decrease the current
setting.

F
(RIGHT SELECT
key function)

SHDN

Press the RIGHT SELECT key to turn the boiler OFF.

Press the RIGHT SELECT key to turn the boiler ON.

Press the RIGHT SELECT key to cancel the shutdown operation.

SAVE

Press the RIGHT SELECT key to save the current change.

HOME

Press the RIGHT SELECT key to return to the Status Screen and
upload parameter changes.

Installation & Operation Manual

Maintenance

Maintenance and annual startup
Table 12A Service and Maintenance Schedules

Service technician
(see the following pages for instructions)

Owner maintenance

(see the Knight Wall Mount User’s Information
Manual for instructions)

General:
• Address reported problems
• Inspect interior; clean and vacuum if
necessary;

• Check boiler area

Daily

• Clean condensate trap and fill with fresh
water

• Check pressure/temperature
gauge

ANNUAL START-UP

• Check for leaks (water, gas, flue,
condensate)
• Verify flue and air lines in good condition
and sealed tight

• Check vent piping

• Check system water pressure/system
piping/expansion tank

• Check air piping

• Check control settings

Monthly

• Check ignition and flame sense
electrodes (sand off any deposits; clean
and reposition)

• Check relief valve
• Inspect condensate drain system

• Check wiring and connections

• Check air vents

• Perform start-up checkout and
performance verification per Section 10
of this manual.
• Flame inspection (stable, uniform)

• Test low water cutoff (if used)

Periodically

• Flame signal (at least 10 microamps at
high fire)
• Clean the heat exchanger if flue
temperature is more than 54°F above
return water temperature.

If combustion or performance
indicate need:

• Check air and vent termination
screens

Every
6 months

• Reset button (low water cutoff)

• Check boiler piping (gas and
water) for leaks
• Operate relief valve

• Clean heat exchanger
• Remove and clean burner using
compressed air only
• Clean the blower wheel

End
of season
months

• Shut boiler down (unless boiler
used for domestic hot water)

Installation & Operation Manual

Maintenance

 WARNING

(continued)

Follow the Service and maintenance procedures given throughout this manual and in component literature
shipped with the boiler. Failure to perform the service and maintenance could result in damage to the boiler
or system. Failure to follow the directions in this manual and component literature could result in severe
personal injury, death, or substantial property damage.

 WARNING The boiler should be inspected annually only by a qualified service technician. In addition, the maintenance
and care of the boiler designated in Table 12A and explained on the following pages must be performed to
assure maximum boiler efficiency and reliability. Failure to service and maintain the boiler and system could
result in equipment failure.
 WARNING

Electrical shock hazard – Turn off power to the boiler before any service operation on the boiler except as
noted otherwise in this instruction manual. Failure to turn off electrical power could result in electrical shock,
causing severe personal injury or death.

Address reported problems
1. Inspect any problems reported by the owner and correct
before proceeding.

Inspect boiler area

1. Verify that boiler area is free of any combustible materials,
gasoline and other flammable vapors and liquids.
2. Verify that air intake area is free of any of the contaminants
listed in Section 1 of this manual. If any of these are
present in the boiler intake air vicinity, they must be
removed. If they cannot be removed, reinstall the air and
vent lines per this manual and the Knight Wall Mount
Service Manual.

3. After the condensate trap is cleaned or serviced, it must be
checked to ensure that it is installed and draining properly.
Figure 12-1 Condensate Trap

Inspect boiler interior

1. Remove the front access cover and inspect the interior of
the boiler.
2. Vacuum any sediment from inside the boiler and
components. Remove any obstructions.

Inspect condensate trap
Monthly inspection:
1. The condensate trap should be inspected monthly to
ensure the trap is properly installed and connected to the
condensate pipe under the boiler, see FIG. 12-1.
2. The condensate line should be inspected monthly
for obstructions, making sure it allows free flow for
condensate to drain.
3. Inspect the neutralizing kit (if installed) monthly to
ensure the condensate is draining properly, and there is
still an adequate amount of neutralizing agent available.
Annual cleaning:
1. The condensate trap should be cleaned at least once
annually, or at the end of each heating season, by
removing the bottom cap and cleaning out any sediment
that exists.
2. The provided condensate trap is equipped with a ball
that acts as a seal against harmful flue gases escaping in
case there is no condensate in the trap. If this ball is not
present, flue gases may be able to pass through the trap
when there is no condensate present, resulting in an
unsafe environment. It is important to check and make
sure the ball is still located in the trap, acting as a seal
against flue gases at least once annually and after every
cleaning.

FLOAT BALL

CONDENSATE DRAIN

BOTTOM CAP

 WARNING

IMG00046

It is in the best interest of the end user
to make sure the ball is present and the
condensate trap is filled with water during
all times of boiler operation to avoid flue
gas emission from the condensate drain
line. Failure to have the ball present or to
fill the trap could result in severe personal
injury or death.

Check all piping for leaks
 WARNING

Eliminate all system or boiler leaks.
Continual fresh makeup water will reduce
boiler life. Minerals can build up in sections,
reducing heat transfer, overheating heat
exchanger, and causing heat exchanger
failure. Leaking water may also cause severe
property damage.

1. Inspect all water and gas piping and verify to be leak free.
2. Look for signs of leaking lines and correct any problems
found.
3. Check gas line using the procedure found in Section 7 Gas Connections.

Installation & Operation Manual

Maintenance

Flue vent system and air piping
1.

Visually inspect the entire flue gas venting system and air
piping for blockage, deterioration or leakage. Repair any
joints that show signs of leakage. Verify that air inlet pipe
is connected and properly sealed.

Verify that boiler vent discharge and air intake are clean
and free of obstructions.
 WARNING Failure to inspect for the above conditions
and have them repaired can result in severe
personal injury or death.

Check water system
1. Verify all system components are correctly installed and
operational.
2. Check the cold fill pressure for the system. Verify it is
correct (must be a minimum of 12 psi).
3. Watch the system pressure as the boiler heats up (during
testing) to ensure pressure does not rise too high.
Excessive pressure rise indicates expansion tank sizing or
performance problem.
4. Inspect air separators.

Check expansion tank
1. Expansion tanks provide space for water to move in
and out as the heating system water expands due to
temperature increase or contracts as the water cools.
Tanks may be open, closed or diaphragm or bladder
type. See Section 6 - Hydronic Piping for suggested best
location of expansion tanks and air eliminators.

Check boiler relief valve
1. Inspect the relief valve and lift the lever to verify flow.
Before operating any relief valve, ensure that it is piped
with its discharge in a safe area to avoid severe scald
potential. Read Section 6 - Hydronic Piping before
proceeding further.
Following installation, the valve lever
 WARNING must be operated AT LEAST ONCE
A YEAR to ensure that waterways are
clear.
Certain naturally occurring
mineral deposits may adhere to the valve,
rendering it inoperative. When manually
operating the lever, water will discharge
and precautions must be taken to avoid
contact with hot water and to avoid water
damage. Before operating lever, check
to see that a discharge line is connected
to this valve directing the flow of hot
water from the valve to a proper place of
disposal. Otherwise severe personal injury
may result. If no water flows, valve is
inoperative. Shut down the boiler until a
new relief valve has been installed.

 WARNING

Safety relief valves should be re-inspected
AT LEAST ONCE EVERY THREE YEARS,
by a licensed plumbing contractor or
authorized inspection agency, to ensure
that the product has not been affected by
corrosive water conditions and to ensure
that the valve and discharge line have not
been altered or tampered with illegally.
Certain naturally occurring conditions may
corrode the valve or its components over
time, rendering the valve inoperative. Such
conditions are not detectable unless the
valve and its components are physically
removed and inspected. This inspection
must only be conducted by a plumbing
contractor or authorized inspection agency
– not by the owner. Failure to re-inspect the
boiler relief valve as directed could result in
unsafe pressure buildup, which can result in
severe personal injury, death, or substantial
property damage.

2. After following the warning directions in this manual, if
the relief valve weeps or will not seat properly, replace the
relief valve. Ensure that the reason for relief valve weeping
is the valve and not over-pressurization of the system due to
expansion tank waterlogging or undersizing.

Inspect ignition and flame sense
electrodes
1. Remove the ignition and flame sense electrodes from the
boiler heat exchanger access cover.
2. Remove any deposits accumulated on the ignition/flame
sense electrode using sandpaper. If the electrodes cannot be
cleaned satisfactorily, replace with new ones.
3. Replace ignition/flame sense electrode, making sure gasket
is in good condition and correctly positioned.

Check ignition ground wiring
1. Inspect boiler ground wire from the heat exchanger access
cover to ground terminal strip.
2. Verify all wiring is in good condition and securely attached.
3. Check ground continuity of wiring using continuity meter.
4. Replace ground wires if ground continuity is not satisfactory.

Check all boiler wiring
1. Inspect all boiler wiring, making sure wires are in good
condition and securely attached.

Check control settings
1. Set the SMART SYSTEM control module display to
Parameter Mode and check all settings. See Section 1 of
the Knight Wall Mount Service Manual. Adjust settings if
necessary. See Section 1 of the Knight Wall Mount Service
Manual for adjustment procedures.
2. Check settings of external limit controls (if any) and adjust
if necessary.

Installation & Operation Manual

Maintenance

(continued)

Perform start-up and checks
1. Start boiler and perform checks and tests specified in
Section 10 - Start-up.
2. Verify cold fill pressure is correct and that operating
pressure does not go too high.

Check burner flame
1. Inspect flame through observation window.
2. If the flame is unsatisfactory at either high fire or low fire,
turn off boiler and allow boiler to cool down. Remove the
burner and clean it thoroughly using a vacuum cleaner
or compressed air. Do not use compressed air to clean
burner if performed inside a building.
3. Remove the burner, reference FIG. 12-2 (page 77).
4. When replacing the burner, ensure gasket is in good
condition and positioned correctly (FIG. 12-2).
Figure 12-2 Burner Assembly

BURNER PLATE
GASKET,
BURNER PLATE
INSULATION,
BURNER DOOR
BURNER
GASKET
BURNER

Check flame signal
1. At high fire the flame signal shown on the display should
be at least 10 microamps.
2. A lower flame signal may indicate a fouled or damaged
flame sense electrode. If cleaning the flame sense electrode
does not improve, ground wiring is in good condition,
and ground continuity is satisfactory, replace the flame
sense electrode.
3. See Section 3 - Troubleshooting of the Knight Wall
Mount Service Manual for other procedures to deal with
low flame signal.

Review with owner
1. Review the Knight Wall Mount User’s Information Manual
with the owner.
2. Emphasize the need to perform the maintenance schedule
specified in the Knight Wall Mount User’s Information
Manual (and in this manual as well).
3. Remind the owner of the need to call a licensed contractor
should the boiler or system exhibit any unusual behavior.
4. Remind the owner to follow the proper shutdown procedure
and to schedule an annual start-up at the beginning of the
next heating season.

Cleaning boiler heat exchanger
1. Shut down boiler:
• Follow the “To Turn Off Gas to Appliance” instructions
for the boiler in Section 10 - Startup.
• Do not drain the boiler unless it will be exposed to
freezing temperatures. If using freeze prevention fluid
in system, do not drain.
2. Allow time for the boiler to cool to room temperature if it
has been firing.
3. Remove the nuts securing the heat exchanger access cover
to the heat exchanger and set aside.
4. Remove the heat exchanger access cover and burner.
 WARNING The boiler contains ceramic fiber materials.
Use care when handling these materials per
instructions in the Service Manual. Failure
to comply could result in severe personal
injury.
5. Remove the condensate trap from the bottom of the boiler.
Place a bucket underneath the condensate fitting attached
to the heat exchanger.
6. Use a vacuum cleaner to remove any accumulation on the
boiler heating surfaces. Do not use any solvent.
7. Using a clean cloth dampened with warm water, wipe out
the combustion chamber. Rinse out debris with a low
pressure water supply.
8. Allow the heat exchanger to thoroughly dry.
9. Perform start-up and check-out procedures in the Check
Flame and Combustion - Section 10 - Startup on pages 59
and 62 of this manual.
10. Replace the burner, access cover and condensate trap.
Restore boiler to operation.
 CAUTION

* Do NOT use a metal brush.

Oiled bearing circulators
1. The circulator shipped with the Knight wall mount boiler is
water-lubricated. No oiling is required.
2. Check other circulators in the system. Oil any circulators
requiring oil, following circulator manufacturer’s
instructions. Over-oiling will damage the circulator.
3. Replace the boiler front access cover.

Installation & Operation Manual

Diagrams

Figure 13-1 Ladder Diagram
JUNCTION BOX

120VAC

NEUTRAL GROUND

TERMINAL STRIP
120V SUPPLY "L"

TERMINAL STRIP
120V SUPPLY "N"
1
INTEGRATED CONTROL

ON / OFF
SWITCH

X1-2

SYSTEM
PUMP "L"

X1-4

BOILER
PUMP "L"

X1-3

DHW
PUMP "L"

X1-1

X1-6

2
BLOWER

GND
SYSTEM
PUMP "N"

3.15A
SYSTEM
PUMP

F1
5A

SYSTEM PUMP
RELAY
BOILER PUMP
RELAY

BOILER
PUMP

DHW PUMP
RELAY

F3
.8A

GND
DHW
PUMP "N"

TERMINAL
STRIP

24V DC
SUPPLY

X5-9

GND
BOILER
PUMP "N"

DHW
PUMP

TERMINAL
STRIP

X5-1

120 VAC
X4-3

24 VAC
CONNECTION BOARD
INTEGRATED
CONTROL

CN5-5

LWCO

FLOW

CN7-3

CN7-4

CN5-14

X4-8

SWITCH

CN5-10 X4-12
24 VAC
CN7-2

CN7-1

HEAT/LOOP
DEMAND

1
CN5-7

X4-1

CN5-13

X4-9

CN5-6

X4-2

19
19

HEAT/LOOP
DEMAND

17
HEAT/LOOP
DEMAND

15
15

16
TANK
THERMOSTAT

CN5-12 X4-10

13
13

14
HIGH GAS
PRESSURE
SWITCH

LOW GAS
PRESSURE
SWITCH

CN5-11

X4-11

CN5-3

X4-5

CN5-4

X4-4

INTEGRATED
CONTROL

LOUVER
RELAY COIL

24VAC

LOUVER
PROVING SWITCH

X7
8

RIBBON CABLE

X5-2

PC INTERFACE
ALARM
BELL

INLET
SENSOR

OPERATING
SENSOR

HIGH LIMIT
SENSOR

SILENCING
SWITCH

2
FLUE
SENSOR

6
FLUE
SENSOR

X5-4

RUN-TIME
CONTACTS

X2-2

X5-14

CN5-8

X4-14

X5-8

CN5-2

X4-6

X5-15

CN5-9

X4-13

TR2

CN6

TANK
SENSOR

X1-7

FLAME ROD
SPARK
ROD

24
CN6

SHIELD

27
29

CN6

SHIELD

CN6

32
0-10V

0-10V

40
41
CN8-1

X6-1

42
43

CN8-2

X6-2

SHIELD

CN8-3

X6-3

X5-16

OUTDOOR
SENSOR

+
IN SYS PUMP +
IN BLR PUMP +
OUT RATE +
OUT -

X5-7

2
X4-7

BMS

CN5-1

CN6

SHIELD

GAS VALVE
RELAY

X2-1
X5-13

S3b

21
22

MODBUS

GAS VALVE

X5-5

S3a

CASCADE

X5-11

AIR PRESSURE
SWITCH
X5-12

S1b

CONNECTION
BOARD

ALARM
CONTACTS

S1a

BLOWER

SYSTEM
SENSOR

X5-10

X5-6

M
O
D
B
U
S

CAUTION

HIGH VOLTAGE SPARK LEAD

NOTES:
1. Where possible, switches are shown without utilities (gas, water or
electricity) connected to the unit. As such, actual switch states may
vary from those shown on diagrams depending upon whether utilities
are connected or a fault condition is present.
2. See wiring diagram for additional notes.

BOX DEPICTS
OPTIONAL ITEMS

X4-1

X9-2

X4-2

X9-1

X4-3

X9-3

LOW VOLTAGE
120 VAC
HIGH VOLTAGE
LADDER DIAGRAM
LBL20170 REV D

Installation & Operation Manual

Diagrams

(continued)

Figure 13-2 Wiring Diagram
LOW VOLTAGE
120 VAC
HIGH VOLTAGE

BOX DEPICTS
OPTIONAL ITEMS
BOX DEPICTS
DUAL SENSOR
SINGLE HOUSING

INTEGRATED
CONTROL

SILENCING SWITCH

BELL JUMPER

ALARM BELL

CONNECTION BOARD

ALARM
CONTACTS
RUN-TIME
CONTACTS
24 VAC LOUVER
RELAY COIL
LOUVER
PROVING SWITCH
GAS PRESSURE
SWITCH

FLOW
SWITCH
TANK
THERMOSTAT
HEAT/LOOP
DEMAND
HEAT/LOOP
DEMAND
HEAT/LOOP
DEMAND

3
2
1

11
12
13
14
15
16
17
18
19
20

X-7

TANK
SENSOR
SHIELD
A
B

SHIELD

X1-4

CN5-1
CN5-8
CN5-2
CN5-9
CN5-3
CN5-10
CN5-11
CN5-4
CN5-5
CN5-14
CN5-12
CN5-6
CN5-13
CN5-7

X4-7
X4-14
X4-6
X4-13
X4-5
X4-12
X4-11
X4-4
X4-3
X4-8
X4-10
X4-2
X4-9
X4-1

BK
BK
BK
BK
BK
BK
BK
BK
BK
BK
BK
BK
BK
BK

+ 0-10V
+ 0-10V
+ 0-10V
+ 0-10V
-

SHIELD

MODBUS
OPTION

B
SHIELD

24 VAC
COM

N
L

DHW
PUMP

BOILER
PUMP

SYSTEM
PUMP

ON/OFF
SWITCH
X1-6
X1-5

BK
W

X1-8

X1-1

L
N

L 120V
GND
SUPPLY
N

RWG
1 2 3

BLOWER
1 2 3 4 5

33
34
35
36
37
38
39
40
41
42
43
44

X5-7

X5-16

X5-8

X5-15

X5-9

X5-1

X5-2

X5-10

X5-11

O/BK

X5-4

R/BK

X5-12

X5-6

P/BK

X5-5

W/BK

X5-13

AIR PRESSURE SWITCH
-T

OPERATING SENSOR S1a
-T

CN7-1
CN7-2
CN7-3
CN7-4

HIGH LIMIT SENSOR S1b
-T

CN8-1
CN8-2
CN8-3

LOW
WATER
CUT-OFF

X1-2

TRANSFORMER

CN6

BMS
IN
SYS PUMP
IN
BLR PUMP
OUT
RATE
OUT

X1-3

21
22
23
24
25
26
27
28
29
30
31
32

SYSTEM
SENSOR
OUTDOOR
SENSOR

CASCADE

1
2
3
4
5
6
7
8
9
10

BOX DEPICTS
OPTIONAL
ITEMS

JUNCTION
BOX

INLET SENSOR S2
-T

FLUE SENSOR S3a
-T

X6-3
X6-2
X6-1
X6-4

R BLG

SHIELD
GROUNDING
JUMPER

MODBUS BOARD
MTR-01

X4-1
X4-2
X4-3
X4-4

O
GY
G

X9-1
X9-2
X9-3
X9-4

X5-14

X2-2

X2-1

X1-7

W/R

TR2

X5-1
X5-2
X1-1
X1-2
X1-3

FLUE SENSOR S3b

GAS VALVE
@24VAC
FLAME SENSOR
G
SPARK
ROD
CAUTION HIGH VOLTAGE SPARK LEAD

BK
W
G

Notes:
1. All wiring must be installed in accordance with: local, state, provincial and national code requirements per either N.E.C. in USA or C.S.A. in Canada.
2. If any original equipment wire as supplied with the appliance must be replaced, it must be replaced with wire having same wire gauge (AWG) and rated for a
minimum of 105°C. Exceptions: Replacement high vo ltage spark lead and ribbon cables must be purchased from the factory. Use of a non-approved spark lead
or ribbon cables can lead to operational problems which could result in non-repairable damage to the integrated controller or other components.
3. Actual connector block locations may vary from those shown on diagrams. Refer to actual components for proper connector block locations when using
diagrams to troubleshoot unit.

WIRING DIAGRAM
LBL20169 REV D

Revision A (ECO #C06854) initial release.
Revision B (ECO #C08222) reflects the changes to the water pipe
clearances from 1" to a 1/4" (ECR #R04077), pages 7, 8, and 33 and
changes made to the service clearances (left side) from 24" to 12" (ECR
R04002).
Revision C (ECO #C08645) reflects additional cleaning and inspection
instructions for the condensate trap (page 75).
Revision D (ECO #C09197) reflects additional information added to the
humidity warning on page 7, along with updates made to the SMART
SYSTEM control (ECR #R04523).
Revision E (ECO #C09803) reflects the addition of the new Polypropylene
Vent material section, rearranging the venting section, and the addition
of the AHRI and ASME logos (R05009).
Revision F (ECO #C09843) reflects the addition of the manual air vent in
the outlet tubing and the new condensate trap pipe (R04984).
Revision G (ECO C10297) reflects the addition of the venting notice on
page 16 and updates made to the ignition timing information.
Revision H (ECO C10450) reflects changes made to Table 10A on
page 62.
WH-I-O Rev H
05/12

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