LENNOX Furnace/Heater, Gas Manual L0806204

User Manual: LENNOX LENNOX Furnace/Heater, Gas Manual LENNOX Furnace/Heater, Gas Owner's Manual, LENNOX Furnace/Heater, Gas installation guides

Open the PDF directly: View PDF .
Page Count: 56

Download
Open PDF In Browser	View PDF

INSTALLATION
INSTRUCTIONS

LF WVOX)
®
_ 2006 Lennox Industries Inc.
Dallas, Texas, USA

G61MP SERIES UNITS
GAS UNITS
505,124M
07/2007
Supersedes 09/2006

_)
Technical
_.LLL. Publications
Lithe U.S.A.

Unit Dimensions ...............................
G61MP Parts Identification ......................
Shipping and Packing List .......................
Safety Information ..............................
General .......................................
Combustion, Dilution & Ventilation Air .............
Installation - Setting Equipment ..................
Filters ........................................
Duct System ..................................
Pipe & Fittings Specifications ...................
Vent Piping Guidelines .........................
Joint Cementing Procedure .....................
Venting Practices .............................
Gas Piping ...................................
Electrical .....................................
Integrated Control Board .......................
Unit Start-Up .................................
Gas Pressure Adjustment ......................
High Altitude Information .......................
Other Unit Adjustments ........................
Service ......................................
Ignition Control Board Diagnostic Codes .........
Troubleshooting ...............................
Repair Parts List ..............................
Vent Pipe Sizing Worksheet ....................
Start-Up & Performance Check List ..............

RETAIN THESE INSTRUCTIONS
FOR FUTURE REFERENCE

2
3
4
4
6
6
8
17
17
18
20
21
21
32
34
41
41
43
44
45
47
49
50
55
56
56

A WARNING

Do not store or use gasoline or other
flammable vapors and liquids in the
vicinity
of this or any other appliance.
Installation
and service
must be
performed
by a qualified installer,
service agency or the gas supplier.

WHAT TO DO IF YOU SMELL

• Do not try to light any appliance.
• Do not touch any electrical switch; do not
use any phone in your building.
• Leave the building immediately.
• Immediately
call your gas supplier from a
neighbor's phone. Follow the gas supplier's
instructions.
• If you cannot reach your gas supplier, call
the fire department.

07/07

IIIllllllnlnllllllllllllllllllllllllllll

GAS:

505,124M
Page 1

IIIIIINIIIIIIIIIIIIIIIHIIII

*NOTE - 60C and 60D size units installed in upflow applications that require air volumes over 1800 cfm (850 L/s)
must have one of the following:
1. Single side return air with transition, to accommodate
20 x 25 x 1 in. (508 x 635 x 25 mm) air filter.
Required to maintain proper air velocity.
2. Single side return air with optional RAB Return Air Base
3. Bottom return air.
4. Return air from both sides.
5. Bottom and one side return air.
Refer to Engineering Handbook for additional information.

SUPPLY AIR
OPENING

**Consider sizing requirements for optional IAQ equipment before cutting side return opening.

_OPTIONAL

SIDE RETURN
AIR FILTER KIT
(Either Side)

1 Optional External Side Return Air Filter Kit is not for use
with the optional NAB Return Air Base.

,,_

23-3/4

EXTERNAL.

i_--_

25 (635)

TOP VIEW
28 -1/2

A -_
J_

B-_

(603)

_-9/16(14)

5-112

(724)

r_
....

6-1/2

9/16
91-(14)

19-7116_

COMBUSTION AIR INTAKE
_
(Either Side)

( ly
9- _/_

\ / EXHAUST
AIR OUTLET
Av
(Either Side)

11-5/8 11}5) *-_

(295) Right
9-3/4 (248)
Left

1 OPTIONAL
EXTERNAL
SIDE RETURN
AIR FILTER KIT
(Either Side)

4-1/8
(103)

6-3/4
(171)

3/4 (19)

(Either Side)
_

(476)

{1_2_1
_A
I
I
I

(584)
*OPTIONAL
RETURN CUTOUT
(Either Side)

I
14"*

L
5/8(16)

--I-

3/4 (19)

*Bottom Return
Air Opening

4-1/4
(108)

+*Bottom Return
Air Opening

FRONT VIEW

SIDE VIEW

A
Model No.

INLET

....
I

-I_

,E,,
i ers

ELECTRICAL

(64) _

AIR FLOW

--J_l-

.r_ CONDENSATE
TRAPCONNECTION

°Oo_

,
18-3/4

(Either Side)
\

4-7/8 (124) Right
2-1/4 (57) Left -I_
(1016)

JL--o

GAS
P,P,NG,NLET

_11
_ y\

in.

17-1/2

446

16-3/8

416

406

G61 MP-48C-090
G61MP-60C-090
G61MP-48C-110
G61MP-60C-110

533

19-7/8

454

19-1/2

495

G61MP-60D-135

24-1/2

622

23-3/8

546

584

G61MP-36B-045
G61MP-36B-070

Page 2

G61MP

PARTS

IDENTIFICATION

DuralokPlus TM
HEATEXCHANGER
ASSEMBLY
CABINET

GAS VALVE
AND MANIFOLD

/
FLUE
COLLAR

COMBUSTION
AIR PRESSURE
PROVE SWITCHES*
COMBUSTION
INDUCER

WARM HEADER
(COLLECTOR)
BOX
AIR
CONDENSER

BURNER
ACCESS
PANEL

PRIMARY LIMIT

COLD HEADER
(COLLECTOR)
BOX

--.¢

BLOWER
ACCESS
DOOR

DOOR
INTERLOCK
SWITCH

*G61MP-090 shown.
G61MP-045 and -070
are equipped with
two switches.

-....

SECONDARY
LIMITS (2)

BLOWER
ASSEMBLY

SIGHT
GLASS
CONTROL BOX

FIGURE 1

Page 3

COIL

TheG61MPgasfurnaceisshippedreadyforinstallation
in
theupflow,downflow,
horizontal
leftairdischarge
or horizontalrightairdischargeposition.Thefurnaceis shipped
withthebottompanelin place.Thebottompanelmustbe
removedif theunitis tobeinstalledin upflowapplications
withbottomreturnair.Thebottompanelmustalsoberemovedanddiscarded
inalldownflow
orhorizontal
applications.
Thefurnaceis equippedforinstallation
in naturalgasapplications.
A conversion
kit(ordered
separately)
is required
forusein propane/LP
gasapplications.

The following items may also be ordered separately:
1- Thermostat
1 - Propane/LP changeover kit
Check equipment for shipping damage. If you find any
damage, immediately contact the last carrier.

-&WARNING

The G61MP can be installed as either a Direct Vent or a
Non-Direct Vent gas central furnace.
NOTE - In Direct Vent installations, combustion air is taken
from outdoors and flue gases are discharged outdoors. In
Non-Direct Vent installations, combustion air is taken from
indoors and flue gases are discharged outdoors. See figure 2 for appfications involving roof termination.
DIRECT VENT INSTALLATION
COMBUSTION
AIR INTAKE
OUTSIDE
OF
HOUSE

NON-DIRECT
VENT
INSTALLATION

EXHAUST

EXHAUST
OUTLET

OUTLET

COMBUSTION
AIR

CONDENSATE
DRAIN"_I,

INTAKE INSIDE
OF HOUSE

CONDENSATE
DRAIN

FIGURE 2

Package 1 of 1 contains
1 - Assembled G61MP unit
1 - Bag assembly containing the following:
3 - Screws
3 -Wire nuts
1 - Snap bushing
1 - Snap plug
1 - Wire tie
1 - Condensate
1 - Condensate
2 -2" diameter
1 - 3" diameter
1 -2" diameter

- CAUTION

trap
trap cap
vent / intake plugs
cabinet plug (intake)
debris screen

1 -Logo sticker (for use in downflow applications)
NOTE - G61MP-48C-110 and G61MP-60C-110 units also
include a 2" diameter ABS street elbow, which is shipped
on the blower deck in the heating compartment.
G61MP-60D-135 units are shipped with a 3" to 2"ABS reducing elbow.

Use only the type of gas approved for use with this furnace.
Refer to unit nameplate.
G61MP units are CSA International certified to ANSI
Z21.47 and CSA 2.3 standards.
In the USA, installation of gas furnaces must conform with
local building codes. In the absence of local codes, units
must be installed according to the current National Fuel
Gas Code (ANSl-Z223.1/NFPA
54). The National Fuel
Gas Code is available from the following address:
American National Standards Institute, Inc.
11 West 42nd Street
New York, NY 10036
In Canada, installation must conform with current National
Standard of Canada CSA-B149 Natural Gas and Propane
Installation Codes, local plumbing or waste water codes
and other applicable local codes.
In order to ensure proper unit operation in non-direct vent
applications, combustion and ventilation air supply must be
provided according to the current National Fuel Gas Code
or CSA-B149 standard.
This furnace is CSA International certified for installation
clearances to combustible material as listed on the unit
nameplate and in the tables in figures 7, 12 and 16. Accessibility and service clearances must take precedence over
fire protection clearances.
NOTE- For installation on combustible floors, the furnace
shall not be installed directly on carpeting, tile, or other
combustible material other than wood flooring.
For installation in a residential garage, the furnace must be
installed so that the burner(s) and the ignition source are
located no less than 18 inches (457 mm) above the floor.
The furnace must be located or protected to avoid physical
Page 4

damagebyvehicles.
Whena furnaceis installed
ina public
garage,hangar,or otherbuildingthathasa hazardous
atmosphere,
thefurnacemustbeinstalled
according
torecommended
goodpracticerequirements
andcurrentNationalFuelGasCodeor CSAB149standard.

This furnace design has not been CSA certified for installation in mobile homes, recreational vehicles, or outdoors.

NOTE - Furnace must be adjusted to obtain a temperature
rise within the range specified on the unit nameplate. Failure to do so may cause erratic limit operation.

Lennox does not recommend the use of G61MP units as a

This G61MP furnace may be used as a high-static unit
heater. The G61MP may also be installed in an aircraft
hangar in accordance with the Standard for Aircraft Hangars (ANSI/NFPA No. 408-1990).
Installation in parking structures must be in accordance
with the Standard for Parking Structures (ANSI/NFPA No.
88A-1991 ). Installation in repair garages must be in accordance with the Standard for Repair Garages (ANSI/NFPA
No. 88B-1991).
This G61MP furnace must be installed so that its electrical
components are protected from water.
When this furnace is used with cooling units, it shall be
installed in parallel with, or on the upstream side of, cooling
units to avoid condensation in the heating compartment.
With a parallel flow arrangement, a damper (or other
means to control the flow of air) must adequately prevent
chilled air from entering the furnace. If the damper is manually operated, it must be equipped to prevent operation of
either the heating or the cooling unit, unless it is in the full
HEAT or COOL setting.
When installed, this furnace must be electrically grounded
according to local codes. In addition, in the United States,
installation must conform with the current National Electric
Code, ANSI/NFPA
(ANSI/NFPA
dress:

No. 70. The National Electric Code

No. 70) is available from the following ad-

National Fire Protection Association

Never use an open flame to test for gas leaks. Check all
connections using a commercially available soap solution
made specifically for leak detection.
construction heater during any phase of construction. Very
low return air temperatures, harmful vapors and operation
of the unit with clogged or misplaced filters will damage the
unit.
G61MP units may be used for heating d buildings or structures under construction, if the following conditions are
met:
• The vent system must be permanently
these installation instructions.

installed per

• A room thermostat must control the furnace. The use of
fixed jumpers that will provide continuous heating is not
allowed.
• The return air duct must be provided and sealed to the
furnace.
• Return air temperature range between 60°F (16°C) and
80 °F (27°C) must be maintained.
• Air filters must be installed in the system and must be
maintained during construction.
• Air filters must be replaced upon construction completion.
• The inputrate and temperature rise mustbe setperthe
furnace rating plate.
• One hundred percent (100%) outdoor air must be provided for combustion air requirements during construction. Temporary ducting may supply outdoor air to the
furnace. Do not connect duct directly to the furnace.
Size the temporary duct following these instructions in
section for Combustion, Dilution and Ventilation Air in a
confined space with air from outside.
• The furnace heat exchanger, components, duct system, air filters and evaporator coils must be thoroughly
cleaned following final construction clean-up.

1 Battery March Park
Quincy, MA 02269
In Canada, all electrical wiring and grounding for the unit
must be installed according to the current regulations of the
Canadian Electrical Code Part I (CSA Standard C22.1)
and/or local codes.
NOTE - This furnace is designed for a minimum continuous
return air temperature of 60°F (16°C) or an intermittent operation down to 55°F (13°C) dry bulb for cases where a
night setback thermostat is used. Return air temperature
must not exceed 85°F (29 °C) dry bulb.
The G61MP furnace may be installed in alcoves, closets,
attics, basements, garages, and utility rooms.

Page 5

• All furnace operating conditions (including ignition, input rate, temperature rise and venting) must be verified
according to these installation instructions.
NOTE - The Commonwealth of Massachusetts
lates these additional requirements:

stipu-

• Gas furnaces shall be installed by a licensedplumber or gas fitter only.
• The gas cock must be "T handle" type.
• When a furnace is installed in an attic, the passageway to and service area surrounding the equipment
shall be floored.

Theseinstructions
areintended
asa generalguideanddo
notsupersede
localcodesinanyway Consultauthorities
havingjurisdictionbeforeinstallation
Inadditiontotherequirements
outlinedpreviously,
thefollowinggeneralrecommendations
mustbe considered
wheninstallinga G61MPfurnace:
• Placethefurnaceas closeto thecenterof theairdistributionsystemaspossibleThefurnaceshouldalsobe
locatedclosetothechimneyorventtermination
point
• Whenthefurnaceis installed
innon-direct
ventapplications,donotinstallthefurnacewheredraftsmightblow
directlyintoit Thiscouldcauseimpropercombustion
andunsafeoperation
• Whenthefurnaceis installed
innon-direct
ventapplications,donotblockthefurnacecombustion
airopening
withclothing,boxes,doors,etc Airisneededforproper
combustion
andsafeunitoperation
• Whenthefurnaceis installedin anatticor otherinsulatedspace,keepinsulationawayfromthefurnace
• Whenthe furnaceis installedin an unconditioned
space,considerprovisions
requiredtopreventfreezing
ofcondensate
drainsystem

CAUTION

-&WARNING

NOTE- In Non-Direct Vent installations, combustion air is
taken from indoors and flue gases are discharged outdoors.

WARNING

In the past, there was no problem in bringing in sufficient
outdoor air for combustion, Infiltration provided all the air
that was needed. In today's homes, tight construction practices make it necessary to bring in air from outside for combustion, Take into account that exhaust fans, appliance
vents, chimneys, and fireplaces force additional air that
could be used for combustion out of the house, Unless outside air is brought into the house for combustion, negative
pressure (outside pressure is greater than inside pressure)
will build to the point that a downdraft can occur in the furnace vent pipe or chimney, As a result, combustion gases
enter the living space creating a potentially dangerous situation,
In the absence of local codes concerning air for combustion and ventilation, use the guidelines and procedures in
this section to install G61MP furnaces to ensure efficient
and safe operation You must consider combustion air
needs and requirements for exhaust vents and gas piping
A portion of this information has been reprinted with permission from the National Fuel Gas Code (ANSIZ223 1/NFPA 54) This reprinted material is not the complete and official position of the ANSI on the referenced
subject, which is represented only by the standard in its entirety

If the G61MP is installed as a Non-Direct Vent Furnace,
follow the guidelines in this section.

In Canada, refer to the standard CSA B149 installation
codes

Page 6

important when the furnace is mounted on a platform in a
confined space such as a closet or small equipment room.
Even a small leak around the base of the unit at the platform
or at the return air duct connection can cause a potentially
dangerous negative pressure condition. Air for combustion

ACAUTION

All gas-fired appliances require air for the combustion process. If sufficient combustion air is not available, the furnace or other appliance will operate inefficiently and unsafely. Enough air must be provided to meet the needs of
all fuel-burning appliances and appliances such as exhaust fans which force air out of the house. When fireplaces, exhaust fans, or clothes dryers
same time as the furnace, much more air
sure proper combustion and to prevent a
ficient air causes incomplete combustion
in carbon monoxide.

are used at the
is required to endowndraft. Insufwhich can result

In addition to providing combustion air, fresh outdoor air dilutes contaminants in the indoor air. These contaminants
may include bleaches, adhesives, detergents, solvents
and other contaminants which can corrode furnace components.

and ventilation can be brought into the confined space either from inside the building or from outside.
Air from Inside
If the confined space that houses the furnace adjoins a
space categorized as unconfined, air can be brought in by
providing two permanent openings between the two
spaces. Each opening must have a minimum free area of 1
square inch (645 mm 2) per 1,000 Btu (.29 kW) per hour of
total input rating of all gas-fired equipment in the confined
space. Each opening must be at least 100 square inches
(64516 mm2). One opening shall be within 12 inches (305
mm) of the top of the enclosure and one opening within 12
inches (305 mm) of the bottom. See figure 3.
EQUIPMENT

EXHAUST

The requirements for providing air for combustion and ventilation depend largely on whether the furnace is installed in
an unconfined or a confined space.
Unconfined

SPACE - ALL AIR FROM INSIDE

PIPE

ROOF TERMINA]

_lr
ED

Space

An unconfined space is an area such as a basement or
large equipment room with a volume greater than 50 cubic
feet (1.42 m3) per 1,000 Btu (.29 kW) per hour of the combined input rating of all appliances installed in that space.
This space also includes adjacent rooms which are not
separated by a door. Though an area may appear to be unconfined, it might be necessary to bring in outdoor air for
combustion if the structure does not provide enough air by
infiltration. If the furnace is located in a building of tight
construction with weather stripping and caulking around
the windows and doors, follow the procedures in the air
from outside section.
Confined

IN CONFINED

Space

A confined space is an area with a volume less than 50 cubic feet (1.42 m3) per 1,000 Btu (.29 kW) per hour of the
com-bined input rating of all appliances installed in that
space. This definition includes furnace closets or small
equipment rooms.
When the furnace is installed so that supply ducts carry air
circulated by the furnace to areas outside the space containing the furnace, the return air must be handled by ducts
which are sealed to the furnace casing and which terminate
outside the space containing the furnace. This is especially

Page 7

'-,

•

OPENINGS
(To Adjacent
Unconfined

-SIDE WALL
ERMINATED
EX=
UST PIPE (ALTERATE LOCATION)

_1
-G61MP

III

__pace)

Y
I

h ¢

"l ¢

NOTE - Each opening shall havo a free area of at least ono square
inch per 1,000 Btu (645mm 2 per .29kW) per hour of the total input
rating of all equipment in the enclosure, but not less than 100 square
inches (64516mm. 2).

FIGURE 3
Air from Outside
If air from outside is brought in for combustion and ventilation, the confined space shall be provided with two permanent openings. One opening shall be within 12" (305mm) of
the top of the enclosure and one within 12" (305mm) d the
bottom. These openings must communicate directly or by
ducts with the outdoors or spaces (crawl or attic) that freely
communicate with the outdoors or indirectly through vertical ducts. Each opening shall have a minimum free area of
1 square inch per 4,000 Btu (645mm 2 per 1.17kW) per hour
of total input rating of all equipment in the enclosure. When
communicating with the outdoors through horizontal ducts,
each opening shall have a minimum free area of 1 square
inch per 2,000 Btu (645mm 2 per .59kW) per total input rating of all equipment in the enclosure (See figure 4).

EQUIPMENT IN CONFINED SPACE - ALL AIR FROM OUTSIDE
(Inlet Air from Crawl Space and Outlet Air to Ventilated Attic)
VENTILATION
ROOF TERMINATED
EXHAUST PIPE

EQUIPMENT

IN CONFINED SPACE - ALL AIR FROM OUTSIDE
(All Air Through Ventilated Attic)

LOU-

VERS
(Each end of attic)

ROOF TERMINATED
EXHAUST PIPE

VENTILATION
LOUVERS
(Each end of attic)

II I
OUTLET
AIR

IINATED
JST PIPE
(

"IRNATE

G61MP

ATION)

VENTIL
LOU_.
(For un

INLET
AIR

_.,.,

crawl
/

.' pace)

INLET AIR
(Ends 12"above
bottom)

TERMINATED
EXHAUSTPtPE
(ALTERNATE
LOCATION)

_1 i"

rrrm

NOTE-The inlet and outlet air openings shall each have a free area of
at least one square inch per 4,000 Btu (645mm2per 1.17kW) per hour
of the total input rating of all equipment in the enclosure.

NOTE-The inlet and outlet air openings shall each have a free area
of at least one square inch per 4,000 Btu (645mm2per 1.17kW) per
hour of the total input rating of all equipment in the enclosure.

FIGURE 5
EQUIPMENT IN CONFINED SPACE ALL AIR FROM OUTSIDE

FIGURE 4
If air from outside is brought in for combustion and ventilation, the confined space must have two permanent openings, One opening shall be within 12 inches (305 mm) of the
top of the enclosure and one opening within 12 inches (305
mm) of the bottom, These openings must communicate directly or by ducts with the outdoors or spaces (crawl or attic) that freely communicate with the outdoors or indirectly
through vertical ducts. Each opening shall have a minimum
free area of 1 square inch (645 mm 2) per 4,000 Btu (1,17
kW) per hour of total input rating of all equipment in the enclosure, See figures 4 and 5. When communicating with
the outdoors through horizontal ducts, each opening shall
have a minimum free area of 1 square inch (645 mm 2) per
2,000 Btu (.56 kW) per total input rating of all equipment in
the enclosure, See figure 6,
When ducts are used, they shall be of the same cross-sectional area as the free area of the openings to which they
connect. The minimum dimension of rectangular air ducts
shall be no less than 3 inches (75 mm). In calculating free
area, the blocking effect of louvers, grilles, or screens must
be considered. If the design and free area of protective covering is not known for calculating the size opening required,
it may be assumed that wood louvers will have 20 to 25 percent free area and metal louvers and grilles will have 60 to
75 percent free area. Louvers and grilles must be fixed in
the open position or interlocked with the equipment so that
they are opened automatically during equipment operation,

ROOF TERMINATED
EXHAUST PIPE

SIDE WALL
TERMINATED
EXHAUSTPtPE
(ALTERNATE
LOCATION)

NOTE-Each air duct opening shall have a free area of at least one
square inch per 2,000 Btu (645mm2per. 59kW) per hour of the total
input rating of all equipment in the enclosure, ff the equipment room
is located against an outside wall and the air openings communicate directly with the outdoors, each opening shall have a free area
of at least 1 square inch per 4, 000 Btu (645mm 2per 1.17kW) per
hour of the total input rating of all other equipment in the enclosure.

FIGURE 6

Page 8

&WARNING

Selecta locationthatallowsfor therequiredclearances
thatarelistedonthe unitnameplate.
Alsoconsidergas
supplyconnections,
electricalsupply,vent connection,
condensate
trap anddrainconnections,
andinstallation
andserviceclearances
[24inches(610mm)atunitfront].

Installation Clearances
Top

The unit must be level from front to back and side to side.
NOTE- Units with 1/2 hp blower motors are equipped with
three flexible legs and one rigid leg. The rigid leg is
equipped with a shipping bolt and a flat white plastic washer (rather than the rubber mounting grommet used with a
flexible mounting leg). The bolt and washer must be removed before the furnace is placed into operation. After the bolt and washer have been removed, the rigid leg
will not touch the blower housing.
Allow for clearances to combustible materials as indicated
on the unit nameplate. Minimum clearances for closet or alcove installations are shown in figures 7, 12 and 16.

Left Side

Right Side
J

Bottom (Floor)
...............................................

T ...............................................

Top/Plenum

i
t
i

*Front

1 in. (25 ram)
O

.-................... ....................
T......................
........................
..'
.....................-.........................f...............................................
I

WARNING

Vent

Floor

O:_

*Front clearance in alcove installation must be 24 in. (610 ram).
Maintain a minimum of 24 in. (610 ram) for front service access.
tAllow proper clearances to accommodate condensate trap and
vent pipe installation.
! :_For installations on a combustible floor, do not install the furi nace directly on carpeting, tile or other combustible
materials othi er than wood flooring.

A WARNING

=================================================================================================

FIGURE 7

Return Air -- Upflow

Units

Return air can be brought in through the bottom or either
side of the furnace installed in an upflow application. If the
furnace is installed on a platform with bottom return, make
an airtight seal between the bottom of the furnace and the
platform to ensure that the furnace operates properly and
safely. The furnace is equipped with a removable bottom
panel to facilitate installation.
Markings are provided on both sides of the furnace cabinet
for installations that require side return air. Cut the furnace
cabinet at the maximum dimensions shown on page 2.
NOTE - When air volumes over 1800 cfm (850 L/s) are
required with 60C or 60D models in an upflow application, the following return air options are available:
Upflow

Applications

1 - Return

The G61MP gas furnace can be installed as shipped in the
upflow position. Refer to figure 7 for clearances.

air from

accommodate
(Required
2 - Return

single

side

to maintain
air from

Air Base.

with

transition

which

will

20 x 25 x I in. (508 x 635 x 25 ram) air filter.
proper

single

See figure

side

air velocity.)
with

optional

See figure
RAB

Return

3 - Return

air from

bottom.

4 - Return

air from

both

5 - Return

air from

bottom

sides.
and one

side.

Refer to Engineering Handbook for additional information.

Page 9

Optional Return Air Base
(Upflow Applications Only -- For use with B, C and D cabinets only)
f

f .............. _ f ..............

--D

4 I

231584)

(102)1_l--

Overall
(Maximum)

1 Mihimu"-_
11 (279) I
2

AIR FLOW
FURNACE
_-

Unit side return airopening
14_5.6)/_
_

FRONT

_I ''_
17-1/2 (446) RAB-B (98M60)
21 (533) RAB-C (98M58)
24-1/2 (622) RAB-D (98M59)
FRONT VIEW

OPTIONAL RAB
RETURN AIR BASE

91_

7/8 .__ 4-(22)

1 22-7-16

(570)
Overall
Maximum)

5-5/8
(143)

7-1/4 (184)

'---.

Maximurq

--3/4
(19)

23 (584)

27-5/8 (702)
SIDE VIEW

NOTE- Optional Side Return Air Filter Kits are not for use with RAB Return Air Base.
1 Both the unit return air opening and the base return air opening must be covered by a single plenum or IAQ cabinet.
Minimum unit side return air opening dimensions for units requiring 1800 cfm or more of air (W x H): 23 x 11 in.
(584 x 279 mm).
The opening can be cut as needed to accommodate
plenum or IAQ cabinet while maintaining
dimensions
shown.
Side return air openings must be cut in the field. There are cutting guides stenciled on the cabinet for the side return
air opening. The size of the opening must not extend beyond the markings on the furnace cabinet..
2 To minimize pressure drop, the largest opening height possible (up to 14 inches) is preferred.
NOTE- Optional

Side Return Air Filter Kits are not for use with RAB Return Air Base.
FIGURE
8

G61MP applications which include side return air and
a condensate trap installed on the same side of the
cabinet require either a return air base or field-fabricated transition to accommodate
cessory taller than 14.2".

an optional IAQ ac-

Removing the Bottom Panel
Remove the two screws that secure the bottom cap to the
furnace. Pivot the bottom cap down to release the bottom
panel, Once the bottom panel has been removed, reinstall
the bottom cap. See figure 10.
Removing the Bottom Panel

Side Return Air
(with transition and filter)

20" X 25" X 1"
(508mm X635mm X 25mm)
Air Filter

Screw

Return
Air
Plenum

\/
ottom Cap
Bottom

FIGURE 9

FIGURE 10

Page 10

Levelingan

Upflow Unit

When the side return air inlets are used in an upflow application, it may be necessary to install leveling bolts on the
bottom of the furnace. Use field-supplied corrosion-resist-

Refer to figure 12 for clearances
tions.
• ...............................................................................................

Top

NOTE - The maximum length of the bolt is 1-1/2 inches.
1 - Lie the furnace on its back and drill a 5/16 inch diameter hole in each corner of the furnace's bottom. See figure 11 for the correct location of the holes. Drill through
the bottom panel and the bottom flange of the cabinet.
2 - Install one bolt and two nuts into each hole. Screw the
first nut onto a bolt and then insert the bolt into a hole. A

Left Side

Right Side

flat washer may be added between the nut and the bottom of the unit.

Bottom
&
...............................................

nace base. A flat washer may be added between the
nut and the bottom of the unit.
4 - Adjust the outside nut to the appropriate height and
tighten the inside nut to secure the arrangement.

Downflow Application Installation Clearances

ant 5/16 inch machine bolts (4) and nuts (8). See figure 11.

3 - Screw another nut onto the bolt on the inside of the fur-

,1
T ...............................................

Top

*Front

."................... ....................
T......................
........................
Sides

NOTE - The unit may be tilted back-to-front a maximum of
1". This will ensure proper draining of the heat exchanger.

i
]
i

Vent
...............................................

NC_:

Bolt Installation

_¢

3/8

*Front clearance in alcove installation must be 24 in. (616 ram).
Maintain a minimum of 24 in. (610 ram) for front service access.
tAllow proper clearances to accommodate
condensate
trap and
vent pipe installation.
_:The furnace may be installed on a combustible
wood floor if an
i optional additive base is installed between the furnace and the

Inches (ram)

3/8
Furnace Front

01"

t ................................................

Floor

Leveling

in downflow applica-

1-3/4
(44)

i combustible

floor.

=================================================================================================

FIGURE 12
Installation on Non-Combustible
1-3/4
(44)

Leveling

1 - Cut floor opening keeping in mind clearances listed on
unit rating plate. Also keep in mind gas supply connec-

Leveling Bolt
Locations

Furnace
Bottom

tions, electrical supply, flue and air intake connections
and sufficient installation and servicing clearances.
See table 1 for correct floor opening size.
2 - Flange warm air plenum and lower the plenum into the
opening.

3/8
(10)

Bolt

3/8
(10)

Flooring

3 - Set the unit over the plenum and seal the plenum to
the unit.

1-3/4
(44)

4 - Ensure that the seal is adequate.

I-3/4 (44)

TABLE 1
NON-COMBUSTIBLE
FLOOR OPENING SIZE

FIGURE 11
Downflow

i............................
[......
......
[......

Applications

The unit may be installed three ways in downflow applications: on non-combustible flooring, on combustible flooring
using an additive base, or on a reverse-flow cooling cabinet. Do not drag the unit across the floor in the downflow position. Flange damage will result.
After unit has been properly set in place, position provided
logo over existing logo and affix sticker on front panel.

Page 11

i
i

Model No.

i
i

-t.,

,i 16-5/8

-t.,

I_.................................
In.
I
mm

jBCabinet(17.5") i19-3/4,

jCCabinet(21")

19-3/4

........
i

i
i

502
502

i
i

I_.................................
In.
I
mm

,i 20-1/8 ,i
-t.,

•
•

422

511

i............................
[................
L................
[................
[................
i
'
• DCabmet(245)

3/4

502

, 23

5/8

600

NOTE - Floor opening dimensions listed are 1/4 inch (6 mm) larger than
the unit opening. See dimension drawing on page 2.

•

Installation on Combustible

Flooring

Installation

1 - When unit is installed on a combustible floor, an additive base must be installed between the furnace and

correctly sized opening in floor and installation of cabinet,
2 - When cooling cabinet is in place, set and secure the
furnace according to the instructions that are provided
with the cooling coil, Secure the furnace to the cabinet,
3 - Seal the cabinet and check for air leaks,

See table 2 for opening size to cut in floor.

Return Air Opening

Ak CAUTION

-- Downflow

Units

Return air may be brought in only through the top opening
of a furnace installed in the downflow position.The following steps should be taken when installing plenum:
1 - Bottom edge of plenum should be flanged with a
hemmed edge (See figure 14 or 15).

TABLE 2
ADDITIVE BASE FLOOR OPENING SIZE
Rear

Cabinet

1 - Refer to reverse-flow coil installation instructions for

the floor. The base must be ordered separately for the
following cabinet sizes:
• B cabinet 17,5" - # 11M60
• C cabinet21"-#
11M61
• D cabinet 24,5" - # 11 M62

Frontto

on Cooling

2 - Sealing strips should be used to ensure an airtight seal
between the cabinet and the plenum.

Side to Side

Model

3 - In all cases, plenum should be secured to top of furin.

in.

B Cabinet

(17.5")

559

18 - 3/4

476

C Cabinet

(21")

559

22 - 3/4

578

D Cabinet

(24.5")

559

25 - 3/4

654

nace using sheet metal screws,
4 - Make certain that an adequate seal is made,
PLENUM

---,..,._

(Field Provided)

I_1_ "_

SECURE FROM

2 - After opening is cut, set additive base into opening.
3 - Check fiberglass strips on additive base to make sure
they are properly glued and positioned.

•

4 - Lower supply air plenum into additive base until plenum flanges seal against fiberglass strips.

_..............__UTSI

SEAL,NG
STR,
(Field Provided)

D E CABINET

II /

CABINET

IIJ S,DE
PANEL

......

NOTE - Be careful not to damage fiberglass strips.

Side View

Check for a tight seal.

FIGURE 14

5 - Set the furnace over the plenum.
PLENUM

6 - Ensure that the seal between the furnace and plenum
is adequate.

(Field P rovid e d_"_"_---.._
SEALING

STRIP

ield Provided)

SECURE
FROM
INSIDE CABINET

SUPPLY AIR PLENUM
G61MP UNIT_
PROPERLY

__T

Side View
FIGURE 15

,VE
BASE

FIGURE 13

Page 12

/
,

CABINET
SIDE PANEL

Horizontal

NOTE - The unit must be level front to back and side to

Applications

The G61MP furnace can be installed in horizontal applications with either right- or left-hand air discharge.

side. If the unit is tilted backward, the heat exchanger coil
will not drain properly,
Installation

Refer to figure 16 for clearances in horizontal applications,
Horizontal Application
Installation Clearances

Furnace

in Attic

NOTE - If unit is suspended in attic or crawl space, horizontal support kit (Cat No. 56J18 ordered separately) must be
used to ensure proper unit support and coil drainage.

Right-Hand Discharge
Top

Left End

of Horizontal

Suspended

H===================mmmmmmHHHmmmmmmHHHmmmmmmHHHmmmmmmHHHm.

1 - Select location for unit keeping in mind service and
other necessary clearances. See figure 16.
Right

2 - Provide service platform in front of unit,

End

3 - Fabricate a drain pan fitted with a 1/2 inch or 3/4 inch
N,P,T, fitting.
4Left-Hand Discharge
Top

Using 3/8 inch rods and support frame kit (ordered
separately), fabricate suspension hangers for unit
keeping in mind front service access clearances.

5 - Mount unit on support frame as shown in figure 17,
Unit must be level to ensure proper coil drainage,
Left

End

Right

End

6- Continue with exhaust, condensate

and intake line

piping instructions,
7 - Hang drain pan below support frame as shown in figure 17. Leave 5-1/2 inches for service clearance beTop

]

low unit for condensate trap,

i...................
ron;:
...................
i......................
.......................
i

8 - Route auxiliary drain line so that water draining from

Back

this outlet will be easily noticed by the homeowner,

".................... ....................
i"i ......................
........................
=

Vent

TYPICAL HORIZONTAL

....................
" oor"
...................
T.....................
;;.......................
| ...............................................

CEILING APPLICATION

BLOWER ACCESS

PANEL

3/8 in. RODS

_ ................................................

*Front clearance in alcove installation must be 24 in. (610 ram).
Maintain a minimum of 24 in. (610 ram) for front service access.
**A 5-1/2" service clearance must be maintained below the unit to
provide for servicing of the condensate trap.
_:For installations on a combustible floor, do not install the furnace directly on carpeting, tile or other combustible materials other than wood flooring.

CONNECTION

FIGURE 16
This furnace may be installed in either an attic or a crawlspace. The G61MP may also be installed as a unit heater.
Either suspend the furnace from roof rafters or floor joists,
as shown in figures 18 or 17, or install the furnace on a fieldfabricated raised platform, as shown in figure 19. The unit
must be supported at both ends and beneath the blower
deck to prevent sagging,

Page 13

DRAIN PAN /
SUPPORTFRAME

(to protect

FIGURE 17

finished space)

TYPICAL

HORIZONTAL

ATTIC APPLICATION

(FORCED

INTAKE

AIR FURNACE)

WASHER

AND 2 NUTS

SAFTERS
BRACED FOR
SUPPORT

DRAIN PAN
LAG BOLT

SUPPORT

ROD

(to protect
finished
space)

*Gas connector may be used if acceptable
by the local authority that has jurisdiction.
DRAIN
PAN

SERVICE
PLATFORM

NOTE - Condensate trap and condensate line
must be protected by self-regulating heating
cable and insulation when run through unconditioned spaces.

SUPPORT
FRAME

BLOWER ACCESS
PANEL

FIGURE 18
Platform

Installation

of Horizontal

Unit in Attic

1 - Select location for unit keeping in mind service and
other necessary clearances, See figure 16,
2 - Construct a raised wooden frame and cover frame
with a plywood sheet, Provide a service platform and
drain pan for unit,
EXHAUST
INTAKE

PIPE
*GAS
CONNECTOR

*Gas connector may be
used
for
Canadian
installation
ff acceptable by local authority
having jurisdiction.

Installation of Horizontal Unit
Suspended in Crawl Space
NO TE - If unit is suspended in attic or crawl space, support
frame kit (Cat No 56J18 ordered separately) must be used
to ensure proper unit support and coil drainage.
1 - Select location for unit keeping in mind service and
other clearances, See figure 16,
2 - Using 3/8 inch rods and support frame kit, fabricate
suspension hangers keeping in mind service access
panel clearances,
3 - Install unit on support frame as shown in figure 20. Unit
must be level to ensure proper coil drainage, Leave
5-1/2 inches for service clearance below unit for condensate trap.

RAISED

CONDENSATE
LINE

INTAKE"
SERVICE PLATFORM

SUPPORT
FRAME

PIPE

FIGURE 19
3 - Set unit in drain pan as shown in figure 19, Unit must
be level to ensure proper coil drainage, Leave 5-1/2
inches for service clearance below unit for condensate
trap.
4 - Continue with exhaust, condensate and intake piping
installation according to instructions.

FIGURE 20
4 - Install exhaust and intake piping according to instructions given in following section. Condensate line
should be run into condensate pump if necessary to
meet drain line slope requirements.

Page 14

Platform Installation of Horizontal

DISCHARGE AIR DUCT/GRILLE

CABINET

Unit in Crawl Space
18in, (457 mm) k

1 - Select location for unit, keeping in mind service and
other clearances,
2 - After positioning cement blocks, mount support frame
kit (ordered separately) on top of blocks and install unit
on frame. Unit must be level to ensure proper heat exchanger coil drainage. Leave 5-1/2 inches for service
clearance) for condensate trap.

FIELD-FABRICATE
GRILL CABINET
TO DESIRED DIMENSION

FIGURE 22
3- To ensure proper operation, the duct/grille cabinet
must be at least 18 inches long.
4 - Use #10-16 x 1/2 inch sheet metal screws to secure
duct/grille cabinet to unit, taking care not to damage internal components of unit heater when drilling holes or
installing screws. See figure 23,
5 - Use adjustable, double-deflection grille(s) to distribute
discharge air. Adjust static pressure to be in the 0.06
inch to 0.10 inch w.c. range.

FIGURE 21

3 - Install exhaust and intake piping according to information given in following section, Condensate line should
be run into condensate pump as shown in figure 21.
G61MP Installed

in Unit Heater Applications

Horizontal unit heaters may be installed either suspended
from the ceiling using the support frame kit or mounted on a
field-fabricated raised platform. The condensate trap must
be installed where it can be serviced at a later date,
Unit Heater Discharge Duct Guidelines

DRAIN PAN
(to protect
finished
space)
NOTE - When installing duct/grille cabinet, take care not to damage internal unit
heater components
when drilling holes or instalhng screws.

A field-fabricated and installed discharge air duct and grille
cabinet is suitable for use with the G61MP heater. See figure 22, Keep the following items in mind when constructing
the cabinet,
1 - Outer dimensions of cabinet should match those of the

FIGURE 23
Installation of Horizontal Unit Heater
Suspended from Ceiling
1 - Select location for unit keeping in mind service and
other clearances.

unit heater, so the duct/grille cabinet installs flush with
the unit heater cabinet, See figure 22,

2 - Fabricate a drain pan fitted with 1/2 inch (13 mm) or
3/4 inch (19 mm) N.P.T. fitting.

2 - Flange both ends of duct/grille cabinet so that screws
can be used to secure cabinet to discharge end of unit
heater.

3 - Using 3/8 inch (9 mm) rods and support frame kit (ordered separately), fabricate suspension hangers,
keeping in mind service access panel clearances.

Page 15

4 - Hangdrainpanbelowsupportframeasshowninfigure23,Routeauxiliary
drainlinesothatwaterdraining
fromthisoutletwillbeeasilynoticedbythehomeowner,
5 - Mountuniton supportframeas showninfigure23.
Unitmustbe levelto ensurepropercoildrainage,
Leave5-1/2inchesforserviceclearance
belowunitfor
condensate
trap,
6- Continuewithexhaust,condensate
and intakeline
pipinginstructions,
PlatformInstallationof HorizontalUnitHeater
1 - Selectlocationfor unitkeepingin mindserviceand
othernecessary
clearances.
2 - Constructa raisedwoodenframeandcoverframe
witha plywoodsheet.Provideserviceplatformand
drainpanforunit,Routeauxiliary
drainlinesothatwaterdrainingfromthisoutletwillbeeasilynoticedbythe
homeowner,
3 - Setunitindrainpanasshowninfigure24,Unitmust
be leveltoensurepropercoildrainage,Leave5-1/2
inchesforserviceclearance
belowunitforcondensate
trap.
4 - Continue
withexhaust,condensate
andintakepiping
installation
according
toinstructions
whichfollow.
*GAS CONNECTOR
INTAKE
PIPE

*Gas connector may be
used for Canadian instal_
lation if acceptable by local authority having jurisdiction.

A filter must be in place whenever the unit is operating,
TABLE 3
Furnace
Cabinet Size

Filter Size
Side Return

Bottom Return

17-1/2"

16X25X

1(1)

16X25X1(1)

21"

16X25X

1(1)

20X25X1(1)

24-1/2"

16X25X

1(2)

24X25X1(1)

Use industry-approved standards to size and install the
supply and return air duct system. This will result in a quiet
and low-static system that has uniform air distribution,
NOTE - Operation of this furnace in heating mode (indoor
blower operating at selected heating speed) with an external static pressure which exceeds 0.5 inches w.c. may result in erratic limit operation.
Supply Air Plenum
If the furnace is installed without a cooling coil, a removable
access panel should be installed in the supply air duct. The
access panel should be large enough to permit inspection
(by reflected light) of the heat exchanger for leaks after the
furnace is installed. If present, this access panel must always be in place when the furnace is operating and it must
not allow leaks into the supply air duct system,
Return Air Plenum

RAISE
CONDENSATE

LINE

PLATFORM

FIGURE 24
Return Air -- Horizontal

Applications

Return air may be brought in only through the end of a furnace installed in the horizontal position. The furnace is
equipped with a removable bottom panel to facilitate installation, See figure 10,

This unit is not equipped with a filter or rack, A field-provided filter is required for the unit to operate properly. Table
3 lists recommended filter sizes,

Return air must not be drawn from a room where this
furnace, or any other gas appliance (ie., a water heater), is installed. When return air is drawn from a room, a
negative pressure is created in the room, If a gas appliance
is operating in a room with negative pressure, the flue products can be pulled back down the vent pipe and into the
room, This reverse flow of the flue gas may result in incomplete combustion and the formation of carbon monoxide
gas. This toxic gas might then be distributed throughout the
house by the furnace duct system,
Return air can be brought in through the bottom or either
side of the furnace, If a furnace with bottom return air is
installed on a platform, make an airtight seal between the
bottom of the furnace and the platform to ensure that the
unit operates properly and safely, Use fiberglass sealing
strips, caulking, or equivalent sealing method between the
plenum and the furnace cabinet to ensure a tight seal. If a
filter is installed, size the return air duct to fit the filter frame,

Page 16

All pipe,fittings,primerandsolventcementmustconform
withAmericanNationalStandardInstituteandtheAmericanSocietyforTestingandMaterials(ANSI/ASTM)
standards.The solventshallbefree flowingandcontainno
lumps,undissolved
particles
or anyforeignmatterthatadverselyaffectsthejointstrengthor chemicalresistance
of
thecement,Thecementshallshownogelation,
stratification,or separation
thatcannotberemovedbystirring,Refertothetable4 belowforapproved
pipingandfittingmaterials.

,&, CAUTION

TABLE 4
PIPING AND FITTINGS SPECIFICATIONS
PIPE & FITTING MATERIAL
Schedule 40 PVC (Pipe)
Schedule 40 PVC (Cellular Core Pipe)

ASTM
SPECIFICATION
D1785
F891

Schedule 40 PVC (Fittings)

D2466

SDR-21PVC

(Pipe)

D2241

SDR-26 PVC (Pipe)

D2241

Schedule 40 ABS Cellular Core DWV (Pipe)

F628

Schedule 40 ABS (Pipe)

D 1527

Schedule 40 ABS (Fittings)

D2468

ABS-DWV (Drain Waste & Vent)
(Pipe & Fittings)

D2661

PVC-DWV (Drain Waste & Vent)
Pipe & Fittings)

D2665

Canadian Applications Only - Pipe, fittings, primer and sol-

Primers and solvents must meet ASTM specifications.
PVC primer is specified in ASTM F 656. Use PVC solvent
cement as specified in ASTM D 2564 and ABS solvent cement as specified in ASTM D 2235. Low temperature solvent cement is recommended. Metal or plastic strapping
may be used for vent pipe hangers.
When making ABS joints, pieces can be prepared with a
cleaner. When joining ABS to PVC materials, use PVC solvent cement. Refer to the procedure specified in ASTM
D3138.

Page 17

vent cement used to vent this appliance must be certified to
ULC $636 and supplied by a single manufacturer as part of
an approved venting system. When bonding the vent system to the furnace, use ULC S636 approved One-Step
Transition Cement to bond the pipe to the flue collar, 90 o
elbow or reducing 90 ° elbow as applicable. In addition, the
first three feet of vent pipe from the furnace flue collar must
be accessible for inspection.
Table 5 lists the available exhaust termination kits, as well
as vent pipe equivalencies which must be used when sizing
vent pipe. All Lennox vent terminations are PVC or ABS.

TABLE 5
KITS AND CORRESPONDING

OUTDOOR TERMINATION

EQUIVALENCIES

Vent Pipe Length Equivalency

UNIT
MODEL

Outdoor
Exhaust
Accelerator
(Dia. X
Length)

1-1/2"
Concentric Kit

1-1/2" X 12"

2" X 12"

71M80

Not
Allowed

2-1/2

Outdoor
Exhaust
Accelerator
(Dia. X
Length)

30G79

15F74

69M29

60L46

Not
Allowed

14"

Not
Allowed

2-1/2

Not
Allowed

14"

2" Wall
Plate Kit

22G44
30G28

3" Wall
Plate Kit

44J40
81J20

Not
Allowed

1"*

2-1/2

Not
Allowed

2**

Not
Allowed

2**

Not
Allowed

4**

2-1/2

Not
Allowed

2***

Not
Allowed

2***

Not
Allowed

4***

Not
Allowed

6***

Not
Allowed

10"**

60C-090

60D-135

***For

2" Wall
Ring Kit

3" Concentric
Kit

36B-070

*Requires
**Requires

2" Wall
Kit with
Vent Extension

2" Concentric
Kit

VENT
PIPE
DIA.
(in.)

36B-045

60C-110

(feet)

field-provided
field-provided

not required. Requires field-provided and installed 2" exhaust accelerator.

and installed 1-1/2" exhaust accelerator.
and instafled 2" exhaust accelerator.

use only in non-direct

vent appfications,

when snow riser is

Page 18

The G61MP can be installed as either a Non-Direct Vent
or a Direct Vent gas central furnace.
NOTE - In Non-Direct Vent installations, combustion air is
taken from indoors and flue gases are discharged outdoors. In Direct Vent installations, combustion air is taken
from outdoors and flue gases are discharged outdoors.
Intake and exhaust pipe sizing in Direct Vent applications
and exhaust pipe sizing in Non-Direct Vent applications -Size pipe according to tables 6 and 7. Table 6 lists the minimum equivalent vent pipe lengths permitted. Table 7 lists
the maximum equivalent pipe lengths permitted.
Maximum vent length is defined as:
Total length (linear feet) of pipe,
Plus Equivalent length (feet) of fittings,
Plus Equivalent length (feet) of termination.
NOTE - Include ALL pipe and ALL fittings,
doors and outdoors.

both in

Regardless of the diameter of pipe used, the standard roof
and wall terminations described in section Exhaust Piping
Terminations should be used. Exhaust vent termination
pipe is sized to optimize the velocity of the exhaust gas as it
exits the termination. Refer to table 8.
*NOTE- The exhaust pipe should be offset a minimum of
12 inches to avoid the possibility of water droplets being re-

leased from the exhaust termination. The minimum exhaust vent length is 15 ft. Shorter exhaust vent lengths may
result in the discharge of water droplets from the exhaust
termination, in spite of the 12-inch vertical offset. See figure 25.
Each 90 ° elbow (including those provided with the furnace)
of any diameter is equivalent to 5 feet (1.52m) of vent pipe
of the same diameter. Two 45 ° elbows are equivalent to
one 90 ° elbow of the same diameter. One 45 ° elbow is
equal to 2.5 feet (.76m) of vent pipe of the same diameter.
In some applications which permit the use of several different sizes of vent pipe, a combination vent pipe may be
used. Contact the Application Department for assistance in
sizing vent pipe in these applications.
NOTE - The flue collar on all models is sized to accommodate 2" Schedule 40 flue pipe. When vent pipe which is
larger than 2" must be used in an upflow application, a 2"
elbow must be applied at the flue collar in order to properly
transition to the larger diameter flue pipe. This elbow must
be added to the elbow count used to determine acceptable
vent lengths. Assign an equivalent feet value to this elbow
according to the larger size pipe being used. Contact Lennox' Application Department for more information concerning sizing of vent systems which include multiple pipe
sizes.

Exhaust Pipe Offset

-F

I
I
12" Min..1_
m

_flow and Downflow Application
Rooftop Termination

Upflow and Downflow Application
Side Wall Termination

12" Min. -_

12" ain.

"P_

Horizontal Application
Rooftop Termination

FIGURE 25

Page 19

Horizontal Application
Side Wall Termination

Usethefollowing
stepstocorrectly
sizeventpipediameter,
Refer to Vent Pipe Size Determination
page 53.

Worksheet

on
All cementing of joints should be done according to the
specifications outlined in ASTM D 2855,

1 - Determine the vent termination and its corresponding
equivalent feet value according to table 5.

WARNING

2 - Determine the number of 90 ° elbows required for both
indoor and outdoor (e,g. snow riser) use, Calculate the
corresponding equivalent feet of vent pipe.
3 - Determine the number of 45 ° elbows required for both
indoor and outdoor use, Calculate the corresponding
equivalent feet of vent pipe,

1 - Measure and cut vent pipe to desired length,

4 - Determine the length of straight pipe required,
5- Add the total equivalent feet calculated in steps 1
through 4 and compare that length to the maximum
values given in table 6 for the proposed vent pipe diameter, If the total equivalent length required exceeds
the maximum equivalent length listed in the appropri-

MIN. EQUIV.
VENT LENGTH

045,070,
09O

5 - Uniformly apply liberal coat of PVC primer for PVC or
ABS cleaner for ABS to inside socket surface of fitting
and male end of pipe to depth of fitting socket.

EXAMPLE
5 ft. plus 2 elbows of 2", 2-1/2", 3"
or 4" diameter pipe

110"*

15 ft.*

6 - Promptly apply solvent cement to end of pipe and inside socket surface of fitting. Cement should be applied lightly but uniformly to inside of socket. Take care
to keep excess cement out of socket, Apply second
coat to end of pipe.

5 ft, plus 2 elbows of 2-1/2" 3" or 4"
diameter pipe
5 ft. plus 2 elbows of 3" or 4"
diameter pipe

135"**
*Any approved
length listed.

termination

ma ' be added to the minimum

equivalent

NQ TE - Time is critical at this stage. Do not allow primer to dry before applying cement.

**G61MP-48C-110
and G61MP-60C-110 must have 90 ° street ell (supplied) installed directly into unit flue collar.
***G61MP-60D-135 must have 3" to 2" reducing ell (supplied) installed directly into unit flue collar.

TABLE 7
MAXIMUM VENT PIPE LENGTHS
ALTITUDE

0 - 4500
(0 - 1371 m)

4501-7500
(1372-2286 m)

7501 - 10000
(2287 - 3048 m)

G61MP
MODEL

MAXIMUM EQUIVALENT
LENGTH FEET

3 - Clean and dry surfaces to be joined,
4- Test fit joint and mark depth of fitting on outside of
pipe.

ate table, evaluate the next larger size pipe,
TABLE 6
MINIMUM VENT PIPE LENGTHS
G61MP
MODEL

2 - Debur and chamfer end of pipe, removing any ridges
or rough edges, If end is not chamfered, edge of pipe
may remove cement from fitting socket and result in a
leaking joint,

VENT

2" dia.

2-1/2" dia.

3" dia.

4" dia.

045
070

59
59

65
65

77
78

234
214

090
110*

26
n/a

42
32

72
72

204
179

135"*
045

n/a
59

n/a
65

**'61
77

160
234

070

214

090
110*

26
n/a

42
32

72
72

204
179

135**
045

n/a
59

n/a
65

***46
77

160
234

070
090

59
26

65
42

78
72

214
204

110*

n/a

179

135**

n/a

***46

160

n/a -- Not allowed.
*G61MP-48C-110 and G61MP-60C-110 must have 90 ° street ell (supplied) installed directly into unit flue collar.
**G61MP-60D-135 must have 3" to 2" reducing ell (supplied) installed directly into unit flue collar.
***90 ° elbows used in configuration of G61MP-60D-135 vent, must be limited to 3"sweep elbows.

7 - Immediately after applying last coat of cement to pipe,
and while both inside socket surface and end of pipe
are wet with cement, forcefully insert end of pipe into
socket until it bottoms out, Turn PVC pipe 1/4 turn during assembly (but not after pipe is fully inserted) to distribute cement evenly, DO NOT turn ABS or cellular
core pipe,
NOTE - Assembly should be completed within 20 seconds after last application of cement. Hammer blows
should not be used when inserting pipe.
8 - After assembly, wipe excess cement from pipe at end
of fitting socket, A properly made joint will show a bead
around its entire perimeter, Any gaps may indicate a
defective assembly due to insufficient solvent,
9 - Handle joints carefully until completely set,

The thickness of construction through which vent pipes
may be installed is 24" (610mm) maximum and 3" (76mm)
minimum. If a G61MP furnace replaces a furnace which
was commonly vented with another gas appliance, the size
of the existing vent pipe for that gas appliance must be
checked, Without the heat of the original furnace flue prodPage 20

ucts,the existingventpipeis probablyoversizedforthe
singlewaterheateror otherappliance.
Theventshouldbe
checkedforproperdrawwiththeremaining
appliance.

or roof in order to prevent transmission of vibration to
the structure.
5 - When furnace is installed in a residence where unit is
shut down for an extended period of time, such as a
vacation home, make provisions for draining condensate collection trap and lines.

1 - Userecommended
pipingmaterialsforexhaustpiping.
2 - Securealljointsso thattheyaregas-tightusingapprovedcement,
Suspendpipingusinghangersata minimum
ofevery
5 feet(1.52m)forschedule40 PVCandevery3
STRAPPING
I
(metal, plastic II
feet(.91m)forABS-DWV,
or large wire J[
PVC-DWV,
SPR-21PVC,
andSDR-26PVCpiping.
ties) 0
A suitablehangercanbe
fabricatedby usingmetal
FIGURE 26
or plasticstrappingor a
largewiretie.
3- In areas where piping penetrates joists or interior
walls, hole must be large enough to allow clearance on
all sides of pipe through center of hole using a hanger.
4 - Isolate piping at the point where it exits the outside wall

Exhaust Piping
NOTE - A 2" diameter street ell is located on the blower
deck of 48C-110 and 60C-f10 units. Street ell must be
glued with ABS solvent cement directly into the unit flue
collar. See figure 27. A 3"to 2"reducing ellis Iocated on the
blower deck of the 60D-135 units. In upflow or downflow
applications,
the reducing ell must be glued with ABS solvent cement directly into the unit flue collar.
1 - Choose the appropriate side for venting in upflow or
downflow positions. Exhaust piping exits from the top
of the unit in horizontal air discharge applications.
Glue the field-provided exhaust vent pipe (or provided
street ell or reducing ell in upflow or downflow applications) to the flue collar. All PVC cement joints should
be made according to the specifications outlined in
ASTM D 2855. Refer to pipe and fittings specifications
and gluing procedures.

TYPICAL
EXHAUST
PIPE CONNECTIONS
AND CONDENSATE
TRAP INSTALLATION
IN UPFLOW OR DOWNFLOW DIRECT OR NON-DIRECT VENT APPLICATIONS
(Right-Hand Exit in Upflow Application Shown)

2-1/2",
3", OR
4"

PLUG
TRANSmON
2"
VENT PLUC
(Must be
glued in
place)
PLUG

or
G61MP-045,070
090 with 2-1/2",
3", or 4" vent pipe

4"
2"

TRANSmON

3", OR
2-1/2",
4"

I _

(use only if 4"
pipe is

required)

CONDENSATE
TRAP
Must be installed
on same side as
exhaust piping)

TRANSiTiON
13"
2 ..... [_

G61MP-110 with
2-1/2", 3", OR 4"
vent pipe

*2" diameter street elbow provided,
**3" diameter reducing elbow provided.
***Limit pipe length to 2".

FIGURE 27

Page 21

G61MP-135 with
3" OR 4" vent pipe

4TYPICAL
EXHAUST
PIPE CONNECTIONS
HORIZONTAL DIRECT OR NON-DIRECT VENT
APPLICATIONS
(Horizontal Right-Hand Air
Discharge Application Shown)

Route piping to outside of structure, Continue with
installation following instructions given in piping termination section.

Ak CAUTION
*Limit pipe length to 2"
in G61MPV-110
and
-135 applications.
3", OR
4"
2-1/2",
_>_i

TRANSITION_

G61MP-36B-070
G61
MP-48C-090
G61MP-36B-045
G61MP-60C-090
G61MP-48C-110"
G61MP-60C-110"
G61MP-60C-135*

2"*

DO NOT transition

from

smaller
to larger
pipe
size in horizontal
runs.

,& CAUTION
G61MP-36B-045
G61MP-36B-070
G61 MP-48C-090
G61MP-60C-090

Intake Piping
The G61MP furnace may be installed in either direct vent
or non-direct vent applications. In non-direct vent applications, when intake air will be drawn into the furnace from the
surrounding space, the indoor air quality must be considered and guidelines listed in Combustion, Dilution and
Ventilation Air section must be followed,

The G61MP unit is designed for either left-side or right-side
air intake connections in either upflow or downflow applications. In horizontal applications, air intake must be brought
in through the top. Intake air piping is independent of exhaust piping.

FIGURE 28

Follow the next four steps when installing the unit in direct
vent applications,
where combustion air is taken from
outdoors and flue gases are discharged outdoors. The
provided air intake screen must not be used in direct
vent applications.

A, IMPORTANT

1 - Cement intake piping in slip connector located on the
side of the burner box.

2 - All horizontal runs of exhaust pipe must slope back toward unit. A minimum of 1/4" (6mm) drop for each 12"
(305mm) of horizontal run is mandatory for drainage.
Horizontal runs of exhaust piping must be supported
every 5 feet (1,52m) using hangers,

2 - Use a #7 sheet metal screw to secure the intake pipe
to the connector, if desired, A pilot indentation is provided in the slip connector to assist in locating and
starting the fastener,
3 - Glue the provided 2" plug into the unused air intake
connector on the opposite side of the cabinet.

NOTE - Exhaust piping should be checked carefully to
make sure there are no sags or low spots,

Route piping to outside of structure. Continue with
installation following instructions given in general
guide lines for piping terminations and in intake and

3 - On the opposite side of the cabinet, glue the provided
2" vent plug into the unused flue collar.

exhaust piping terminations for direct vent sections.
Refer to figure 29 for pipe sizes.

Page 22

TYPICAL
AIR INTAKE PIPE CONNECTIONS
UPFLOW OR DOWNFLOW DIRECT VENT APPLICATIONS
(Right-Hand Exit in Upfiow Application Shown)

3" OR
2-1/2",
4"
TRANSITION
2"* [_

TRANSITION

2"* F/_
PLUG
(Must be
glued in
place)

G61MP-36B-045
G61MP-36B-070
G61 MP-48C-090
G61MP-60C-090

G61MP-36B-045
G61MP-36B-070
G61 MP-48C-090
G61MP-60C-090
G61MP-48C-110"
G61MP-60C-110"

G61MP-36B-045
G61MP-36B-070
G61 MP-48C-090
G61MP-60C-090
G61MP-48C-110"
G61MP-60C-110"
G61MP-60C-135*

*Limit pipe length to 2"
in G61MP-110
and
I

- 135 applications.

FIGURE

Follow the next three steps when installing the unit in Non-

TYPICAL AIR INTAKE PIPE CONNECTIONS
HORIZONTAL DIRECT VENT APPLICATIONS
(Horizontal Right-Hand Air Discharge Application Shown)

*Limit pipe
length to 2" in
G51MP-110
and -135
applications.

G61MP-36B-045
G61MP-36B-070
G61 MP-48C-090
G61M P-60C-090
G61MP-48C-110"
G61MP-60C-110"
G61 MP-60C-135*

Direct Vent applications where combustion air is taken
from indoors and flue gases are discharged outdoors.

TYPICAL AIR INTAKE PIPE CONNECTIONS
UPFLOW
(Right-Hand
_

2"*
G61MP-36B-070
G61MP-36B-045
G61 MP-48C-090
G61MP-60C-090

Exit in Upf!ow

Application

Shown)

2-1/2",
3" OR 4"
PLUG
(Must be
glued in
place)

TRANSITION
_

OR HORIZONTAL
NON-DIRECT
VENT APPLICATIONS

TRANSITION
2"*

G61MP-48C-110*
G61MP-60C-110"

INTAKE
DEBRIS
SCREEN

2"*
2"

(Provided)

G61MP-36B-04
G61MP-36B-070
G61 MP-48C-690
G61MP-60C-090

2" _

= ,

NOTE - Debris screen and elbow may be rotated, so that
screen may be positioned to face forward, backward or
downward.
.............
r_ ...................................................................

FIGURE 31

FIGURE 30

Page 23

TYPICAL
AIR INTAKE PIPE CONNECTIONS
DOWNFLOW NON-DIRECT VENT APPLICATIONS
(Right-Hand Exit in Downflow Applications Shown)

2" SWEEP
ELL

INTAKE
DEBRIS
SCREEN
(Provided)

6 in. Max,
PLUG
_lpqU
s t, be
ea in
lace)

PLUG
(g_ust, be
ea I
_L_ace_
I

181n.|

2" SWEEP

INTAKE DEBRIS
SCREEN
(Provided)

ELL
T

Downflow Additive FIIoor Base

Downflow
Evaporator
Coil
0

NOTE

- Debris

screen

may be positioned

screen

and sweep

ell may be rotated,

to face forward, backward

so that

or to the side.

FIGURE 32
1 - Use field-provided materials and the factory-provided
air intake screen to route the intake piping as shown in

Testing for Proper Venting and Sufficient
Air

figures 31 and 32, Maintain a minimum clearance of 3"
(76mm) around the air intake opening. The air intake
opening (with the protective screen) should always be
directed either downward or straight out, Use 2" pipe
and fittings only and make sure that the air intake does
not extend more than 6" beyond the G61MP cabinet,
The air intake connector must not be located near

Combustion

(Non-Direct Vent Applications Only)

WARNING

the floor. To avoid this complication
in downflow
applications
which do not include a downflow
evaporator coil, the intake air routing should be modified as shown in figure 32,
2 - Use a #7 sheet metal screw to secure the intake pipe
to the connector, if desired, A pilot indentation is provided in the slip connector to assist in locating and
starting the fastener,
3 - Glue the provided 2" plug into the unused air intake
connector on the opposite side of the cabinet,

After the G61MP gas furnace has been started, the following test should be conducted to ensure proper venting and
sufficient combustion air has been provided to the G61MP,
as well as to other gas-fired appliances which are separately vented. The test should be conducted while all ap-

Page 24

pliances(bothinoperation
andthosenotinoperation)
are
connected
totheventingsystembeingtested.Iftheventingsystemhasbeeninstalledimproperly,
or if provisions
havenotbeenmadeforsufficientamountsofcombustion
air,corrections
mustbemadeasoutlinedintheprevious
section.
1 - Sealanyunusedopeningsintheventingsystem.
2 - Visuallyinspecttheventingsystemforpropersizeand
horizontal
pitch.Determine
thereis noblockage
orrestriction,leakage,corrosion,or other deficiencies
whichcouldcauseanunsafecondition.
3 - Totheextentthatitispractical,
closeallbuildingdoors
andwindowsandall doorsbetweenthe spacein
whichtheappliances
connected
totheventingsystem
arelocatedandotherspacesof thebuilding.
4 - Closefireplacedampers.
5 - Turnon clothesdryersandanyappliancesnotconnectedto theventingsystem.Turnon anyexhaust
fans,suchasrangehoodsandbathroom
exhausts,
so
theywilloperateatmaximum
speed.Donotoperatea
summerexhaustfan.
6 - Followthe lightinginstructionto placetheappliance
beinginspected
intooperation.Adjustthermostatso
appliance
willoperatecontinuously.
7 - Usetheflameofmatchorcandletotestforspillageof
fluegasesatthedrafthoodreliefopeningafter5 minutesof mainburneroperation.
8- If improperventingis observedduringany of the
abovetests,theventingsystemmustbecorrected
or
sufficientcombustion/make-up
airmustbeprovided.
Theventingsystemshouldbe re-sizedto approach
the minimumsize as determinedby usingthe appropriatetablesinappendix
G inthecurrentstandards
oftheNationalFuelGasCodeANSFZ223.1/NPFA
54
in the U.S.A.,andthe appropriateNaturalGasand
Propaneappliances
ventingsizingtablesin thecurrentstandardoftheCSA-B149
NaturalGasandPropaneInstallation
Codesin Canada.
9 - Afterdetermining
thateachappliance
remaining
connectedto thecommonventingsystemproperlyvents
whentestedas indicated
instep3,returndoors,windows,exhaustfans,fireplacedampersandanyother
gas-burning
applianceto theirpreviousconditionof
use.
General Guidelines for Vent Terminations
rect Vent Installations.

for Non-Di-

In Non-Direct Vent applications, combustion air is taken
from indoors and the flue gases are discharged to the outdoors. The G61MP is then classified as a non-direct vent,
Category IV gas furnace. In Non-Direct Vent applications,
the vent termination is limited by local building codes, In the

Page 25

absence of local codes, refer to the current National Fuel
Gas Code ANSI Z223-1/NFPA 54 in U.S.A., and current
CSA-B149 Natural Gas and Propane Installation Codes in
Canada for details.
Position termination end according to location given in figure 33. In addition, position termination end so it is free
from any obstructions and above the level of snow accumulation (where applicable). The termination should be at
least 12 inches (305mm) from any opening through which
flue products could enter the building.
At vent termination,

care must be taken to maintain

protective coatings over building materials (prolonged
exposure to exhaust condensate can destroy protective
coatings). It is recommended that the exhaust outlet not be
located within 6 feet (1.8m) of a condensing unit because
the condensate can damage the painted coating.
NOTE - If winter design temperature is below 32°F (O°C),
exhaust piping should be insulated with 1/2" (f3mm), Armaflex or equivalent when run through unheated space.
Do not leave any surface area of exhaust pipe open to outside air; exterior exhaust pipe should be insulated with 1/2"
(13mm) Armaflex or equivalent. In extreme cold climate
areas, 3/4" (19mm) Armaflex or equivalent may be necessary. Insulation on outside runs of exhaust pipe must be
painted or wrapped to protect insulation from deterioration.
Exhaust pipe insulation may not be necessary in some
specific applications.
NOTE - During extremely cold temperatures, below
approximately 20°F (6. 7°C), units with long runs of vent
pipe through unconditioned space, even when insulated,
may form ice in the exhaust termination that prevents the
unit from operating properly. Longer run times of at least 5
minutes will alleviate most icing problems. Also, a heating
cable may be installed on exhaust piping and termination to
prevent freeze-ups. Heating cable installation kit is available from Lennox. See Condensate Piping section for part
numbers.

AIMPORTANT

,&IMPORTANT

VENT TERMINATION
CLEARANCES
FOR INSTALLATIONS
IN THE USA AND CANADA*

[]

- G61MP VENT TERMINATION

- AIR INLET OF OTHER APPLIANCE

D
!
A - Clearance above grade - 12 in. (305mm) minimum.
B - Clearance to window or door that may be opened for vent installations
in USA- 12 in (305mm) minimum.
for vent installations
in Canada - 12 in. (305mm) minimum for appliances _ 100,000 Btuh (30 kW);
36 in. (09m) minimum for appliances > 100,000 Btuh (30
kW)
C - Do not position terminations

directly under roof eaves.

D - Clearance to electric meters, gas meters, regulators, and
refief equipment for vent installations
in USA -48 in (1219mm) minimum.
for vent installations
in Canada - see current edition of
CSA B149 Code

E - Clearance to non-mechanical air supply inlet or outlet
for vent installations
in USA -48 in (1219mm) minimum
horizontal and below, 12 in. (305mm) minimum above
for vent installations
in Canada - 12 in. (305mm) minimum for appliances _ 100,000 Btuh (30 kW);
36 in. (09m) minimum for appliances > 100,000 Btuh (30
kW).
F - Clearance to mechanical air supply inlet -for vent installations
in USA - 36 in. minimum (914mm).
G - Clearance to mechanical air supply inlet -for vent installations
in Canada - 72 in. (1829mm)
mum

mini-

H - Do notpoint terminations into recessed areas such as window wells, stairwells or alcoves.
J - Do notposition

terminations

directly above a walkway.

* Note (I) Dimensions are from the current edition of The National Fuel Gas Code - ANSI-Z223.1/NFPA
54 for USA installations. In Canada, refer to current edition of CSA B149 installation codes. Local codes or regulations may require different clearances.
(11)In Non-Direct Vent installations, combustion air is taken from indoors and the flue gases are discharged to the outdoors.

FIGURE 33

Page 26

Details of Intake and Exhaust Piping Terminations for
Direct Vent Installations
NOTE - In Direct Vent installations, combustion air is taken
from outdoors and flue gases are discharged to outdoors,
Intake and exhaust pipes may be routed either horizontally
through an outside wall or vertically through the roof. In attic or closet installations, vertical termination through the
roof is preferred, Figures 34 through 42 show typical terminations.
1 - Exhaust and intake exits must be in same pressure
zone, Do not exit one through the roof and one on the
side. Also, do not exit the intake on one side and the
exhaust on another side of the house or structure.
2 - Intake and exhaust pipes should be placed as close
together as possible at termination end (refer to illustrations). Maximum separation is 3" (76mm) on roof
terminations and 6" (152mm) on side wall terminations.
3 - If necessary, install a field-provided reducer to adapt
larger vent pipe size to termination pipe size.
4 - On roof terminations, the intake piping should terminate straight down using two 90 ° elbows (See figure
34),
5 - Exhaust piping must terminate straight out or up as
shown, In rooftop applications, a reducer may be required on the exhaust piping at the point where it exits
the structure to improve the velocity of exhaust away
from the intake piping, See table 8.
NOTE - Care must be taken to avoid recirculation of
exhaust back into intake pipe,
6 - On field supplied terminations for side wall exits, exhaust piping should extend a minimum of 12 inches
(305mm) beyond the outside wall. Intake piping
should be as short as possible, See figure 35,
7 - On field supplied terminations, a minimum separation
distance between the end of the exhaust pipe and the
end of the intake pipe is 8 inches (203mm),
8 - If intake and exhaust piping must be run up a side wall
to position above snow accumulation or other obstructions, piping must be supported every 3 ft. (.9m) as
shown in figure 26. Refer to figure 38 for proper piping
method. In addition, WTK wall termination kit must be
extended for use in this application. See figure 41.
When exhaust and intake piping must be run up an
outside wall, the exhaust piping is reduced to 1-1/2"
(38mm) after the final elbow, The intake piping may be
equipped with a 90 ° elbow turndown. Using turndown
will add 5 feet (1.5m) to the equivalent length of the
pipe.

Page 27

9 - Based on the recommendation of the manufacturer, a
multiple furnace installation may use a group of up to
four termination kits WTK assembled together horizontally, as shown in figure 40,
TABLE 8
EXHAUST PIPE TERMINATION SIZE REDUCTION
G61MP
MODEL

Exhaust Pipe Size

045 and 070

2", 2-1/2", 3" or 4"

090

2", 2-1/2", 3" or4"

110
135

2-1/2", 3" or4"
3" or 4"

2"*
2"*

*Approved 3" concentric temfination

Inches(ram)

Termination

kit temfinates

3(76) MAX.

PIPE
/

with 2-5/8" ID pipe.

SIZE TERMINATION

Pipe Size

1-1/2"

PER

TABLE

UNCONDITIONED

6,,(2o
M,N I JIII//P:

ATT,C
SPACE

_._t_ C:?q3IHF/" v'- "- 1,2,,
(13)FOAM
Ir./

I I_,-L/It

12" (305) ABOVE
AVERAGE SNOW

_1"[_,_/"/11
,,_ I_'/

INSULATION IN
UNCONDITIONED
SPACE

II 'm-

It II

AOOOMO T
3" (76) OR

2"(51)PVC

PROVIDE
FOR

SUPPORT

INTAKE

EXHAUST

AND
LINES

[-_

___

DIRECT VENT ROOF TERMINATION
(15F75 or 44J41)

KIT

FIGURE 34

12" (305) MAX.
1/2" (13) ARMAFLEX
INSULATION IN
UNCONDITIONED
SPACE

_unless

supportel)

|
1/2" (13)
_L/'ARMAFLEX

,_/

INSULATION
SIZE

PROVIDED
FIELD/_
REDUCER MAY
BE REQUIRED
TO ADAPT
LARGER VENT
PIPE SIZE TO
TERMINATION

•

6" (152)
MAXIMUM

OUT
WALL
2" (51) PVC/
COUPLING

"_ TERMINATION
PIPE PER
TABLE 8

/
MINIMUM

TOP VIEW WALL RING KIT
(15F74)

FIGURE 35

Inches (mm)

EXHAUST
TERMINATION

EXHAUST VENT

12" (305) ABOVE
AVERAGE SNOW
ACCUMULATION

/
Inches

(mm)

INTAKE
TERMINATION

INTAKE__
VENT

FIELD-PROVIDED
REDUCER MAY BE REQUIRED
TO ADAPT LARGER VENT
PiPE SIZE TO TERMINATION
EXHAUST

INTAKE

DIRECT VENT CONCENTRIC ROOFTOP TERMINATION
(71M80, 69M29 or 60L46)

1/2" (13) Foam Insulation
in Unconditioned Space

EXHAUST VENT

INTAKE VENT
OUTSIDE WALL

Inches (ram)

DIRECT VENT WALL TERMINATION KIT
(22G44, 44J40, 30G28 or 81J20)

INTAKE
TERMINATION

FIGURE 39

EXHAUST
TERMINATION

EXHAUST

Side View

REDUCER MAY
BE REQUIRED
TO ADAPT
LARGER VENT
PIPE SlZETO /
TERMINATION
PROVIDED
FIELDI,

FIGURE 36
Inches (mm)

Front View

INTAKE
EXHAUST
VENT

12" (305) Min.
above grade.

FIELD-PROVIDED
REDUCER MAY
BE REQUIRED TO
ADAPT LARGER
VENT PIPE SIZE
TO TERMINATION

'NTAKE
VENT

J i_55_
,,
"-_/

!_,o(i_

Inches(mm)

_-_]

EXHAUST VENT

INTAKE

VENt
_

12" (305) MAX. for 2" (51)
(untess supported)

_ ,, (3.05)

Front View

Inches (ram)

UNCONDITIONED
SPACE

" Side View

OPTIONAL VENT TERMINATION FOR MULTIPLE UNIT
INSTALLATION OF DIRECT VENT WALL TERMINATION KIT WTK

WALL

FIGURE 40
SIZE
TERMINATION
PIPE PER
TABLE 8.

PROVIDE SUPPORT
FOR INTAKE AND
EXHAUST LINES EVERY
36" (914)
FIELD-PROVIDED
REDUCER MAY
BE REQUIRED TO
ADAPT LARGER
VENT PIPE SIZE
TO TERMINATION

12" (305) ABOVE
AVERAGE SNOW
ACCUMULATION

1/2" (13) FOAM
INSULATION IN
UNCONDITIONED
SPACE

See venting

_'-'_1

<457)|

FIGURE 37

DIRECT

18" MAX.

DIRECT VENT CONCENTRIC WALL TERMINATION
(71M80, 69M29 or 60L46)

OUTSIDE

[_2!i I
.....

VENT

SIDE VIEW
WALL
RING

(15F74)
table 6 for maximum
venting

1/2" (13) FOAM
INSULATION

TERMINATION
lengths

with this arrangement.

FIGURE 38

Page 28

12" (305) MAX. for 2" (51)
20" (508) MAX. for 3" (76)
_.=(unless
supported)=..= I

Inches

INTAKE
AIR

//
//
//
//

(305)

_ _ EXHAUST
AIR

-L J

LI_I

]- I_ I

I I II

COVER EXHAUST
VENT WITH
1/2" (13)
FOAM
INSULATION

12"

(rnrn)

U'r'

INTAKE
AIR

8" (203) ]
Minimu._

I"_--

EXHAUST
AIR

12"(305)
ABOVE

!!!i!i!!ii_:i_:i_:i_:i_:i_:i_:ii:iii!:!iiiiiiiiiiiii!;

GRADE

5"
(127)

12" MIN.
(305)
Above Grade

Side View

GRADE

fffffffSffSffSffS_

WALL TERMINATION

Front View
DIRECT VENT TERMINATION
KIT (22G44, 44J40, 30G28 or 81J20) EXTENDED

VENT FOR GRADE CLEARANCE

FIGURE 41
G61MP DIRECT VENT APPLICATION
USING EXISTING CHIMNEY

STRAIGHT-CUT
OR
ANGLE-CUT
IN DIRECTION
OF ROOF SLOPE *

Inches(ram)

12
30_nm)

INTAKE

P_PE

FNSULAT_ON(op_al)
SHEET
METAL TOP

ALTERNATE

_
XX

PLATE

MINIMUM
i2"
(305ram) ABOVE
ROOF

If_//
A IF/

ACCUMULAT.O :
/
II

SHOULDER
OF FITTINGS
PROVIDE SUPPORT
OF PIPE ON TOP PLATE
i

PIPE PER TABLE 8.

_¢//

ABOVEAVE./
SNOW I

EXHAUSTVENT
1M' (13ram)
WEATHERPROOF
INSULATOR

SIZE TERMINATION

-.--_

12" (305ram)t

(203mm

.,v

-r--q-,

PROVIDE
SUPPORT

FOR EXHAUST

LINES

1.14

I1 I

-A ia- PACE

t
NON-DIRECT

*SIZE TERMINATION
PIPE PER TABLE 8.

VENT ROOF TERMINATION

KIT

(15F75 or 44J41)

FIGURE 43

NOTE - Do not discharge exhaust gases directjy into any chimney or vent stack. If vertical discharge through an existing unused chimney or stack is required,
insert piping
inside chimney until the pipe open end is above top of chimney and terminate
as illustrated. In any exterior portion of chimney,
the exhaust vent must be insulated.

FIGURE 42
Details of Exhaust Piping Terminations for Non-Direct
Vent Applications
Exhaust pipes may be routed either horizontally through an
outside wall or vertically through the roof, In attic or closet
installations, vertical termination through the roof is preferred. Figures 43 through 46 show typical terminations,
1 - Exhaust piping must terminate straight out or up as
shown, The termination pipe must be sized as listed in
table &The specified pipe size ensures proper velocity required to move the exhaust gases away from the
building.
2 - On field supplied terminations for side wall exits, exhaust piping should extend a maximum of 12 inches
(305mm) beyond the outside wall, unless support is
provided in the horizontal section. See figure 44.

Page 29

12" (305) Max. for 2" (51)
Unless Supported
1/2" (13) ARMAFLEX
INSULATION IN
UNCONDITIONED
SPACE

1/2" (13)

I .._ARMAFLEX
FIELD-PROVIDED
REDUCER MAY t .........
BE REQUIRED TO
ADAPT LARGER _

_._

=_.

VENT PIPE SIZE
TO TERMINATION

INSULATION

Pp_

=k_

PVC REDUCER
SIZE TERMINATION
PIPE PER TABLE 8.

Inches (mm)

NON-DIRECT

TOP VIEW
VENT WALL RING KIT
(15F74)

FIGURE 44

3 - Ifexhaustpipingmustberunupa sidewalltoposition
abovesnowaccumulation
or otherobstructions,
pipingmustbesupported
every3 feet(.9m)asshownin
figure26.Refertofigure45forproperpipingmethod.
Whenexhaustpipingmustberunupanoutsidewall,
anyreduction
inexhaustpipesizemustbedoneafter
thefinalelbow.

sate trap should extend below the unit. A 5-1/2" service
clearance is required for the condensate trap. Refer to figure 47 for condensate trap locations.
CONDENSATE TRAP LOCATIONS
(Unit shown in upfiow position)
Horizontal

Inches(mm)

downflow

UNCONDITIONED
SPACE
OUTSIDE

Horizontal

left and

12" (305) Max. for 2" (51)
Unless Supported

optional

...................................................
right and
h"i
r--

..................................
_ .....
_/
_
--_]

downflow

optional

WALL

Lil I_
HI I_J

PROVIDE SUPPORT
FOR EXHAUST LINES
EVERY 30 'I (914)

I MINATION
I

PiPE

TABLE
8"

PER

Optional [--

12" (305) ABOVE

FIELD-PROVIDED
REDUCER MAY BE

upflow

_
_
_ _

Optional
upflow

REQUIRED TO
/ZZZZ:ZZZZ:Z==_
ADAPT LARGER
[_[IF
VENT PIPE SIZE TO
TERMINATION

1/2" (13) FOAM
INSULATION IN
UNCONDITIONED
SPACE
NON-DIRECT

1/2" (13) FOAM
INSULATION
SIDE VIEW
VENT WALL RING

FIGURE 47

TERMINATION

(15F74)

1 - Determine which side condensate piping will exit the
unit. Remove plugs from the condensate collar at the
appropriate location on the side of the unit.

FIGURE 45
G61MP NON-DIRECT VENT APPLICATION
USING EXISTING CHIMNEY
SIZE TERMINATION
PIPE PER TABLE 8.

NOTE - The condensate trap is factory-shipped with
two rubber O-rings and two rubber clean-out caps
instafled. Check to make sure that these items are in

STRAIGHT-CUT
OR
' ANGLE CUT iN DIRECTION
OF ROOF SLOPE

place before installing the trap assembly.
EXHAUST VENT
1/2" (13rnrn)
WEATHERPROOF
INSULATION

(76m_
203mm)
38

MINIMU
12"
(_5mm)ABOVE
AVERAGE:NOW
ACCUMULATION

SHOULDER

PROVIDE
OF

PIPE

FI_INGS

SUPPORT

TOP

PLATE

SHEET
METALTOP
PLATE

3 8
(76ram
203rnm)

Install condensate trap onto the condensate collar.
Use provided HI/LO screws to secure two upper
flanges of the trap to the collar, Use provided sheet
metal screw to secure bottom trap flange to side of
unit, See figure 48,
NOTE - In upflow and downflow applications, condensate trap must be installed on the same side as
exhaust piping.

EXTERIOR
PORTION OF
CHIMNEY

TOFORM
SEAL

/_SOLAT_

CAUTION
NOTE - Do not discharge exhaust gases directly into any chimney or vent stack. If vertical discharge through an existing unused chimney or stack is required, insert piping
inside chimney until the pipe open end is above top of chimney and terminate
as it]ustrated.

In any exterior

portion

of chimney,

the exhaust

vent

must

be insutated.

FIGURE 46
Condensate Piping
This unit is designed for either right- or left-side exit of condensate piping in either upflow or downfiow applications;
however, it must be installed on the same side of the unit as
the exhaust piping. In horizontal applications, the conden-

3 - Glue the field-provided coupling or pipe to the trap.
Install a tee and vent pipe near the trap.

Page 30

NOTE - The condensate trap drain stubs (both sides)
have an outer diameter which will accept a standard
3/4" PVC coupling. The inner diameter of each stub
will accept standard 1/2" diameter PVC pipe.

NOTE - Vinyl tubing may be used for condensate
drain. Tubing must be 1-1/4" OD X 1" ID and should be
attached to the drain stubs on the trap using a hose
clamp.
4 - Glue the field-provided drain line to the tee. Route the
drain line to an open drain, As an alternate, clear vinyl
tubing may be used to drain condensate away from
the trap, Secure the vinyl tubing to the drain stubs on
the trap using a hose clamp, Do not overtighten the
hose clamp,
Condensate line must be sloped downward away from
condensate trap to drain, If drain level is above condensate trap, condensate pump must be used, Condensate drain line should be routed within the conditioned space to avoid freezing of condensate and
blockage of drain line, If this is not possible, a heat
cable kit may be used on the condensate trap and line.
Heating cable kit is available from Lennox in various
lengths; 6 ft. (1.8m) - kit no. 26K68; 24 ft. (7.3m) - kit
no, 26K69; and 50 ft, (15,2m) - kit no. 26K70.

installation, prime trap per procedure outlined in Unit
Start-Up section.
6 - Glue the provided cap onto the unused condensate
drain line stub.
CONDENSATE

ASSEMBLY

HI/LO SCREWS
O-RINGS

(DO NOT use power
driver. Hand-tighten
using screw driver.)

/VENT

NIPPLE

TEE
CAP

NIPPLE

COUPLING
_

CAUTION

CLEAN-OUT ACCESS
(both sides)

CONDENSATE
SCREW

FIGURE 48
5 - If unit will be started immediately upon completion of

Page 31

TRAP

AIMPORTANT
-&CAUTION
MANUAL MAIN SHUT-OFF
VALVE WILL NOT HOLD --

,WARNING

FURNACE

ISOLATE
GAS VALVE
NORMAL TEST PRESSURE _]_
CAP -------_t_

1 - Gas piping may be routed into the unit through either
the left- or right-hand side. Supply piping enters into
the gas valve from the side of the valve as shown in
figure 51.
2 - When connecting gas supply, factors such as length of
run, number of fittings and furnace rating must be considered to avoid excessive pressure drop. Table 9 lists
recommended pipe sizes for typical applications.
NOTE - Use two wrenches when connecting gas piping to avoid transferring torque to the manifold.

FIGURE 49
Leak Check
After gas piping is completed, carefully check all piping
connections (factory- and field-installed) for gas leaks. Use
a leak detecting solution or other preferred means.
The furnace must be isolated from the gas supply system
by closing its individual manual shut-off valve during any
pressure testing of the gas supply system at pressures less
than or equal to 1/2 psig (3.48 kPa, 14 inches w.c.).

3 - Gas piping must not run in or through air ducts, clothes
chutes, chimneys or gas vents, dumb waiters or elevator shafts. Center gas line through piping hole. Gas
line should not touch side of unit. See figure 51.

,IMPORTANT

4 - Piping should be sloped 1/4 inch per 15 feet (6mm per
5.6m) upward toward the gas meter from the furnace.
The piping must be supported at proper intervals, every 8 to 10 feet (2.44 to 3.05m), using suitable hangers
or straps. Install a drip leg in vertical pipe runs to serve
as a trap for sediment or condensate.

&WARNING

5 - A 1/8" N.P.T. plugged tap or pressure post is located
on the gas valve to facilitate test gauge connection.
See figures 58 and 59.
6 - In some localities, codes may require installation of a
manual main shut-off valve and union (furnished by installer) external to the unit. Union must be of the
ground joint type.
U pflow Application

Upflow Application
Right Side Piping

AUTOMATIC

Left Side Piping

GASVALVE

(Standard)

(Alternate)

(with manual
shut-off valve)

MANUAL
MAIN SHUT-OFF
VALVE

[

r
GROUND
JOINT
UNION

MANUAL
MAIN SHU%OFF
VALVE

JOINT
UNION
DRIP LEG

DRIP LEG

FIELD
PROVIDED
AND INSTALLED

FIGURE 50

Page 32

Horizontal Applications
Possible Gas Piping Configerations
MANUAL
MAIN SHUT-OFF
VALVE

M AN UAL
MAIN SHUT-OFF
VALVE

J
GROUND
JOINT
UNION

DRIP

Horizontal Application
Left-Side Air Discharge

DRIP LEG

LEG

Horizontal Application
Right-Side Air Discharge

["_--

MANUAL
MAIN SHUT-OFF
VALVE
(With 1/8in. NPT
Plugged Tap
Shown)
JOINT
UNION
DRIP LEG

FIGURE 51
TABLE 9
GAS PIPE CAPACITY - FT3/HR (kL/HR)
Nominal
Iron Pipe Size
-Inches(ram)

Internal
Diameter
-Inches(ram)

Length
10

(3.048)

(6.096)

(9.144)

40
(12.192)

of Pipe-Feet(m)

50
(15.240)

60
(18.288)

70
(21.336)

1/4
(6.35)
3/8
(9.53)

,364
(9.246)

43
(1.13)

29
(.82)

24
(.66)

20
(.57)

18
(.51)

16
(.45)

15
(.42)

.493
(12.522)

95
(2.69)

65
(1.84)

52
(1.47)

45
(1.27)

40
(1.13)

36
(1.02)

1/2
(12.7)

.822
(17.799)

175
(4.96)

120
(3.40)

97
(2.75)

82
(2.32)

73
(2.07)

3/4
(19.05)

.624
(20.930)

360
(10.19)

250
(7.06)

200
(5.66)

170
(4.81)

1
(25.4)

1.049
(26.645)

660
(19.25)

465
(13.17)

375
(10.62)

1-1/4
(31.75)

1,380
(35.052)

1400
(39.64)

950
(26.90)

1-1/2
(38.1)

1.610
(40.694)

2100
(59.46)

2
(50.8)

2,067
(52.502)

2-1/2
(63.5)

8O
(24.384)

9O
(27.432)

100
(30.480)

33
(.73)

14
(.40)
31
(.88)

13
(.37)
29
(.82)

12
(.34)
27
(.76)

66
(1.67)

61
(1.73)

57
(1.61)

53
(1.50)

5o
(1.42)

151
(4.26)

138
(3.91)

125
(3.54)

118
(3.34)

110
(3.11)

lO3
(2.92)

320
(9.06)

265
(6.07)

260
(7.36)

240
(6.60)

22o
(6.23)

205
(5.80)

195
(5.52)

770
(21.60)

660
(18.69)

580
(16.42)

530
(15.01)

490
(13.67)

46o
(13.o3)

430
(12.18)

400
(11.33)

460
(41.34)

1160
(33.41)

990
(28.03)

900
(25.46)

810
(22.94)

750
(21.24)

69o
(19.54)

650
(18.41)

620
(17.56)

3950
(111.65)

2750
(77.87)

2200
(62.30)

1900
(53.60)

1660
(47.57)

1520
(43.04)

1400
(39.64)

13oo
(36.81)

1220
(34.55)

1150
(32.56)

2,469
(67.713)

6300
(176.39)

4350
(123.17)

3520
(99.67)

3000
(84.95)

2650
(75.04)

2400
(67.96)

2250
(63.71)

2050
(58.05)

1950
(55.22)

1850
(52.38)

3
(76.2)

3,068
(77.927)

11000
(311.48)

7700
(216.03)

6250
(176.98)

5300
(150.07)

4750
(134.50)

4300
(121.76)

3900
(110.43)

3700
(lO4.77)

3450
(97.69)

3250
(92.03)

4
(101.6)

4.026
(102.260)

23000
(651.27)

15800
(447.39)

12800
(362.44)

10900
(306.64)

9700
(274.67)

6600
(249.18)

6100
(229.36)

7500
(212.37)

7200
(203.88)

6700
(189.72)

NOTE - Capacity given in cubic feet of gas per hour (kilo liters of gas per hour) and based on O.60 specific gravity gas.

Page 33

ELECTROSTATIC DISCHARGE (ESD)
Precautions and Procedures

&CAUTION

The unit is equipped with a field make-up box. The makeup box may be moved to the right side of the furnace to facilitate installation, If the make-up box is moved to the right
side, the excess wire must be pulled into the blower
compartment. Secure the excess wire to the existing harness to protect it from damage,
Refer to figure 54 and table 10 for field wiring and figure 57
for schematic wiring diagram and troubleshooting,
1 - Select circuit protection and wire size according to the
unit nameplate. The power supply wiring must meet
Class I restrictions,
2 - Holes are on both sides of the furnace cabinet to facilitate wiring,

INTERIOR MAKE-UP BOX INSTALLATION

3 - Install a separate disconnect switch (protected by either fuse or circuit breaker) near the furnace so that
power can be turned off for servicing,
4 - Before connecting the thermostat or the power wiring,
check to make sure the wires will be long enough for
servicing at a later date, Remove the blower access
panel to check the length of the wire,

MAKE-UP
BOX

Right Side

5- Complete the wiring connections to the equipment.
Use the provided unit wiring diagram and the field wiring diagram shown in figure 54 and table 10, Use
18-gauge wire or larger that is suitable for Class II rating for thermostat connections,
6 - Electrically ground the unit according to local codes or,
in the absence of local codes, according to the current
National Electric Code (ANSI/NFPA No, 70) for the

FIGURE 52

USA and current Canadian Electric Code part 1 (CSA
standard C22.1) for Canada, A green ground wire is
provided in the field make-up box.
NOTE - The G61MP furnace contains electronic com-

INTERIOR MAKE-UP BOX INSTALLATION

Left _\side

__==_

_
_

ponents that are polarity sensitive. Make sure that the
furnace is wired correctly and is properly grounded.

MAKE-UP
BOX

FIGURE 53

7- One line voltage "HUM" 1/4" spade terminal is provided on the furnace control board. Any humidifier
rated up to one amp can be connected to this terminal
with the neutral leg of the circuit being connected to
one of the provided neutral terminals. See figure 55 for
control board configuration. This terminal is energized
in the heating mode when the combustion air inducer
is operating,
8 - One line voltage "EAC" 1/4" spade terminal is provided
on the furnace control board, Any electronic air cleaner
rated up to one amp can be connected to this terminal
with the neutral leg of the circuit being connected to
one of the provided neutral terminals, See figure 55 for
control board configuration, This terminal is energized
when the indoor blower is operating,

Page 34

9 - One24V"H"terminal
is provided
onthefurnace
control
boardterminalblock.Any humidifierratedup to 0.5
ampcanbeconnected
tothisterminalwiththeground
legof thecircuitbeingconnected
to eithergroundor
the"C"terminal,Seefigure55forcontrolboardconfiguration,

instructionpackaged
withthedualfuelthermostat,
Indoor Blower Speeds
1 - When the thermostat is set to "FAN ON," the indoor
blower will run continuously on the low heat speed
when there is no cooling or heating demand.
2 - When the G61MP is operating in the high-fire or lowfire heating mode, the indoor blower will run on the corresponding heating speed,
3 - When there is a cooling demand, the indoor blower will
run on the corresponding cooling speed.

10-Installthe roomthermostat
accordingtothe instructionsprovidedwiththe thermostat,
Seetable10for
fieldwiringconnections
in varyingapplications.
If the
furnaceisbeingmatched
witha heatpump,refertothe

TYPICAL G61MP FIELD WIRING DIAGRAM
120V ACC

HIGH HEAT
PRESSURE
SLOB(2) _
SVITCH

StBB(2)
LOV HEAT
PRESSURE

LI _1

.
--

SWITCH

SIO
_

INI]UCER ROTOR

S 13

AIR
PRIMARY COMBUSTION
_D_KUP
L"G_S_zmll Jg4

GAS

ECDNDARYGVI
V/_V[

NIGH HEAT
PRESSURE
SVITCH

"410

BURRERS
, ,O
$47
FLAME
ROLL[)JT

FLAME
SENSOR

IGNITOR

RL_

PRESSURE
SVITCH

$47
FLAME
,.;159
[------qROt.LOUT

$12B(I) [_

riil
__

SWITCH

P159

SWITCH
(I)S_1
SECONDARY
LIMIT

TI
TRANSFOR_R

®
(2)$21
SEC{_qDARY
LIMIT
C_8
,I-CIRCUIT
BREAKER
P5B

, ®
C4
CAPACITOR

I])®®@
®®®G]

@
INDOOR
BLDVER
MOTOR

LINE
_BASS

_GENOTES

FIGURE 54

Page 35

VOLTAGE FIELD
INSTALLED
II VOLTAGE FIELD WlRINE
OPTIONAL

COMPONENTS

TABLE 10
Field Wiring Applications

Thermostat

1 Heat/1

Cool

DIP Switch and Jumper Settings (See figure 55)
W915
W951
DIP Switch 1
Two-Stage
Heat Pumps
Cooling
ON

Intact

NOTE - Use DiP
switch 2 to set second-stage heat ON
delay,
QFFIO minutes,
ON-15 minutes.

Wiring Connections

Sl
T'STAT

CONTROL
TERM. STRIP

OUTDOOR
UNIT

@
®

®.

®-

_>.

®.

w_'%_ER

@
1 Heat / 2 Cool

Cut

Intact

NOTE - Use DiP
switch 2 to set second-stage heat ON
delay.
OFF- 10 minutes.
ON-15 minutes.

Page 36

Sl
T'STAT

CONTROL
TERM. STRIP

®
®
@.
@.

®
®
@
@
@

OUTDOOR
UNIT

®
@
@

TABLE 10
Field Wiring Applications

(Continued)

DIP Switch and Jumper Settings (See figure 55)
DIP Switch 1

W915
Two-Stage
Cooling

W951
Heat Pumps

OFF

Cut

Intact

Thermostat

2 Heat / 2 Cool

2 Heat/1

Cool

OFF

Intact

Wiring Connections

$1
T'STAT

CONTROL
TERM. STRIP

@
@
@

@
@

$1
T'STAT

CONTROL
TERM. STRIP

OUTDOOR
UNIT

@
®
®
®

4_
®
®
®

®
EXISTING

W915 _._PER

Page 37

TWO-STAGE

INTEGRATED

1/4"QUICK

poooq

-1

(.O

[

E-COM
= D_D_AG
NOSTIC

CONTROL BOARD
CONNECT TERMINALS

HUM: 120 VAC OUTPUTTO HUMIDIFIER
EAC : 120 VAC OUTPUTTO ELECTRONICAIR CLEANER
XMFR : 120 VAC OUTPUT TO TRANSFORMER
LI
: 120 VAC INPUT TO CONTROL
SENSE = 120MAC OUTPUT TO FLAME SENSER
NEUTRALS=

120 VAC NEUTRAL

PARK = DEAD TERMINAL FOR UNUSED BLOWER LEAD
HEAT LOW = 120 MAC OUTPUT TO CIRC BLWR -- LOW HT SPEED
AND CONTINUOUS FAN
HEAT HIGH/COOL LOW = 120 VAC OUTPUT TO CIRC BLWR -HIGH HEAT AND LOW COOL SPEED
COOL HIGH = 120 VAC OUTPUT TO ClRC BLWR -- HIGH COOL SPEED

I_1

LEDs
STATU$_

[

D
Wl W2

CONNECTIONS

HEAT DEMAND FROM IST STAGE T'STAT
HEAT DEMAND FROM 2ND STAGE T'STAT
MANUAL FAN FROM T'STAT
THERMOSTAT 2nd STAGE COOL SIGNAL
THERMOSTAT l_t STAGE COOL SIGNAL
THERMOSTAT SIGNAL GROUND CONNECTED TO TRANSFORMER
ON-BOARD
GROUND (TR) & CHASIS GROUND (GRD)
JUMPERS R= CLASS 2 VOLTAGE TO THERMOSTAT
1= ERROR CODE RECALL
H= 24V HUMIDIFIER OUTPUT
L= LENNOX SYSTEM OPERATION MONITOR
O= THERMOSTAT SIGNAL TO HEAT PUMP REVERSING VALVE

DO00
00(]
000

l]TIo° 0 :

DIP SWITCH FUNCTIONS
FUNCTION

DIP SWITCH(ES)

,W95_

(TB1)

WI:
W2:
G:
Y2:
YI:
C:

DIP

SWITCHES

THERMOSTAT

Y2 YI c(3)ll{z)(1)H

1 -- 2 Staqe T'stat
2 -- 2nd Staqe Delay
3 & 4 -- Heat Off Delay
5 -- Cool Off Delay

FIGURE 55

Page 38

Selects
Second
Heatinq
Cooling

t/stat type (sin qle or two-staqe)
staqe ON delay (sin qle-staqe t'stat)
fan OFF delay
fan OFF delay

INTEGRATED CONTROL BOARD DIP SWITCH SETTINGS AND JUMPERS
8NB STAGE BELAY (HTG)

COOL OFF BELAY (BLOWER)

SINGLE STAGE
THERMOSTAT
(TIMEDSTAGING) _:{;i!
_
>.

L,<,

[RANSFr__9_R

UNIT

P156

S5I _
R[]l_

Sl
THERN_TAT

i@@@@@@@1
,

L ..........

CONTRoLINTEQ_ATED

................

@
A_
INTEGRATED
CONTROL

_4V POVER
PROVII_D
OPTIONAL
HUMIDIFIER
l_NAN])

FOR
I_JRING HEAT

l
)

SETTIt_

_FAt,'LT

SUPPLIED

IS FOR A _ STAGE TReRNOSTAT
ACE VIRE

I_TANTTO PR£V_NT MOTOR DORNOUT,NEVER CQNt_CT MORE
THAN ONE MOTOR LEAD TO ANY OHE CONNECTION,
PARK TERNINAL IS A L_OVERED
ALL L_4USED MOTOR LEADS F_;T
TO THE PARK TERMINAL,

TERMINAL,
RE WIRe])

USE _R
E_'_T_
O_T
0113 USE]) l_ 090,110, AND 13'3 L_ITS

_ovoR
Nt]TOR
A
ZL_

JACK/REUG-INBUCER

FIELD

TD!

J 156

F_TEIRY

C4
CAPACITOR

(

JACK/PLU_T_
AIR INI_UFJ_R
JACK/PLUG SECI]N_ARY LIMIT

JUMPER V915 FROM YI TO YE IS FACTORY INSTALLED
AT A92 CONTROL BOA_& LEAVE
IN FOR ONE STA£,E
COCL THERF_)TAT,
CUT JUROR YI TO Y_ FOR
TV_ STA6E COOL THERNDSTAT

C_
CIRCUIT
BREAKER

J_
J,PI3_

THERROSTAT H_AT ANTICIPATION

(2)Si?,l
SEC(]NDARY
LIMIT

'(-4--1--_

FORMINAL BOARD

CHART

(I)_I

070

FOR

045, AND

FOR

090,110 AN])

UNITS
135

DI@.Y.

ONLY

UNITS

ONLy

CUT V951 JUMPER FROR 0 TO R, LAELED
"HEAT PLkVP% AT Ag2 CONTROL _OARD,
VFEN USE]) FOR _
F[J_L hPPLICAT_
TERMINAL
#1 IS USED FDR ERROR
CODE
RECALL ONLy, SEE INSTALLATIDN

TVD

STA_

k @@@@ _))

®1
A92
INTEGRATE])
CONTROL

I
I
I

-....
-_REk_]TES

LINE VTITAGE FIELD INSTALLED
_AS_
II VOLTA_
FIELD VIRIN_
_TIDEb_.

TYPICAL SYSTEN SHOVN FOR ]) H[AT/_
_
VITH
A CONV_NTD_NAL TJ_J_JSTAT, _EE INSTALLAT])_
INSTRUCTIONS FOR EONReCTION TO OTHER
E_IPReNT
AND ACCESSORIES

C])_NPONERTS

FIGURE 57

Page 40

TAB LE 11
Heating Blower-Off Delay Switch Settings

G61MPunitsare equippedwith a two-stageintegrated
control.Thiscontrolmanagesignitiontimingand fan off
delaysbasedon selectionsmadeusingthe controldip
switchesandjumpers.The controlincludesan internal
watchguard
featurewhichautomatically
resetstheignition
controlwhenit hasbeenlockedout.Afteronehourofcontinuousthermostatdemandforheat,thewatchguard
will
breakandremakethermostat
demandto thefurnaceand
automatically
resetthecontroltorelightthefurnace.
DIPSwitchSettings--Figure56
Switch1 -- ThermostatSelection-- This unitmaybe
usedwitheithera single-stage
or two-stagethermostat.
Thethermostat
selection
ismadeusinga DIPswitchwhich
mustbeproperlypositioned
forthe particular
application.
TheDIPswitchis factory-positioned
for usewitha twostagethermostat.
Ifa single-stage
thermostat
istobeused,
theDIPswitchmustberepositioned.
a - Select "OFF' for two-stage heating operation conb-

trolled by a two-stage heating thermostat (factory setting);
Select "QN" for two-stage heating operation controlled by a single-stage heating thermostat. This setting provides a timed delay before second-stage heat
is initiated.

Blower Off Delay
(Seconds)
60
90
120
180

Switch 3

Switch 4

Off
Off
On
On

On
Off
Off
On

Switch 5 -- Cooling Blower-Off Delay -- The cooling
blower-off delay (time that the blower operates after the
cooling demand has been satisfied) can be adjusted by
moving switch 5 on the integrated control board. The
switch is factory-set in the OFF position, which provides a
cooling blower-off delay of 45 seconds. If the switch is
toggled to the ON position, it will provide a 2-second cooling blower-off delay
On-Board Jumper W951 -- Figure 56
On-board jumper W951, which connects terminals R and O
on the integrated control board, must be cut when the furnace is installed in applications which include a heat pump
unit and a thermostat which features dual fuel use. If the
jumper is left intact, terminal "O" will remain energized eliminating the HEAT MODE in the heat pump.

Switch 2 -- Second Stage Delay (Used with SingleStage Thermostat Only) -- This switch is used to determine the second stage on delay when a single-stage thermostat is being used. The switch is factory-set in the OFF
position, which provides a 10-minute delay before secondstage heat is initiated. If the switch is toggled to the ON
position, it will provide a 15-minute delay before secondstage heat is initiated. This switch is only activated when
the thermostat selector jumper is positioned for SINGLEstage thermostat use.

On-Board Jumper W915 -- Figure 56
On-board jumper W915, which connects terminals Y1 and
Y2 on the integrated control board, must be cut if two-stage
cooling will be used. If the jumper is not cut the outdoor unit
will operate in first-stage cooling only.

FOR YOUR SAFETY READ BEFORE OPERATING

A, WARNING

Switches 3 and 4 -- Heating Blower-Off Delay -- The
heating blower-on delay of 45 seconds is not adjustable.
The heating blower-off delay (time that the blower operates
after the heating demand has been satisfied) can be adjusted by moving switches 3 and 4 on the integrated control
board. The unit is shipped from the factory with a heating
blower-off delay of 90 seconds. The heating blower off
delay affects comfort and is adjustable to satisfy individual
applications. Adjust the blower off delay to achieve a supply air temperature between 90 ° and 110°F at the exact
moment that the blower is de-energized. Longer off delay
settings provide lower supply air temperatures; shorter settings provide higher supply air temperatures.Table 11 provides the blower off timings that will result from different
switch settings.

Page 41

A,WARNING

4 - This furnace is equipped with an ignition device which
automatically lights the burners. Do not try to light the
burners by hand,

ACAUTION

5 - Remove the upper access panel.

Priming Condensate

Trap

The condensate trap should be primed with water prior to
start-up to ensure proper condensate drainage. Either pour
10 fl, oz. (300 ml) of water into the trap, or follow these steps
to prime the trap:
1 - Follow the lighting instructions to place the unit into operation,

6 - White Rodgers 36E Gas Valve - Switch gas valve lever
to OFF, See figure 58 for the White Rodgers 36E valve,
Honeywell VR8205 Gas Valve - Turn knob on gas
valve clockwise _
to OFF, Do not force, See figure
59,
7 - Wait five minutes to clear out any gas. If you then smell
gas, STOP! Immediately call your gas supplier from a
neighbor's phone. Follow the gas supplier's instructions. If you do not smell gas go to next step,

2 - Set the thermostat to initiate a heating demand,

WHITE RODGERS 36E SERIES GAS VALVE

3 - Allow the burners to fire for approximately 3 minutes,
4-

Adjust the thermostat
mand,

HIGH FIRE
MANIFOLD
PRESSURE
ADJUSTMENT
ON SIDE
(under cap)

to deactivate the heating de-

5 - Wait for the combustion air inducer to stop, Set the
thermostat to initiate a heating demand and again allow the burners to fire for approximately 3 minutes.
6-

Adjust the thermostat to deactivate the heating demand and again wait for the combustion air inducer to
stop. At this point, the trap should be primed with sufficient water to ensure proper condensate drain operation,

MANIFOLD

TAP ON SIDE
INLET PRESSURE
TAP ON SIDE

BEFORE LIGHTING the unit, smell all around the furnace
area for gas, Be sure to smell next to the floor because
some gas is heavier than air and will settle on the floor.

LOW FIRE MANIFOLD
PRESSURE ADJUSTMENT
ON SIDE (under cap)

GAS VALVE SHOWN IN OFF POSITION

FIGURE 58

The gas valve on the G61MP may be equipped with either a
gas control knob or gas control lever, Use only your hand to
push the lever or turn the gas control knob. Never use tools,
If the the lever will not move or the knob will not push in or
turn by hand, do not try to repair it, Call a qualified service
technician. Force or attempted repair may result in a fire or
explosion.

HONEYWELL VR8205 SERIES GAS VALVE
HIGH FIRE
ADJUSTING SCREW
(under cap)

MANIFOLD
PRESSURE
TAP

Placing the furnace into operation:
G61MP units are equipped with an automatic ignition system, Do not attempt to manually light burners on this furnace. Each time the thermostat calls for heat, the burners
will automatically light. The ignitor does not get hot when
there is no call for heat on units with this ignition system,

LOW FIRE
(under cap)
_URE
TAP
GAS VALVE SHOWN

IN OFF

POSITION

FIGURE 59

a,WARNING

8 - White Rodgers 36E Gas Valve - Switch gas valve lever
to ON. See figure 58 for the White Rodgers 36E valve,
Honeywell VR8205 Gas Valve - Turn knob on gas
valve counterclockwise _
to ON, Do not force.

Gas Valve Operation (Figures 58 and 59)

9 - Replace the upper access panel,

1 - STOP! Read the safety information at the beginning of
this section.

10- Turn on all electrical power to to the unit,

2 - Set the thermostat to the lowest setting,

NOTE - When unit is initially started, steps 1 through 11
may need to be repeated to purge air from gas fine.

3 - Turn off all electrical power to the unit,

11- Set the thermostat to desired setting,

Page 42

12- Iftheappliance
willnotoperate,
followtheinstructions
"TurningOffGastoUnit"andcallyourservicetechnicianor gas supplier.
Turning Off Gas to Unit
1 - Set the thermostat to the lowest setting,
2 - Turn off all electrical power to the unit if service is to be
performed,
3 - Remove the upper access panel.
4 - White Rodgers 36E Gas Valve - Switch gas valve lever
to OFF,
Honeywefl VR8205 Gas Valve - Turn knob on gas
valve clockwise _
to OFF, Do not force,
5 - Replace the upper access panel,

Gas Flow (Approximate)
1 - Operate unit at least 15 minutes before checking gas
flow. Determine the time in seconds for one revolutions of gas through the meter, A portable LP gas meter (17Y44) is available for LP applications.
2 - Compare the number of seconds and the gas meter
size in table 12 to determine the gas flow rate, Multiply
the gas flow rate by the heating value to determine the
unit input rate, If manifold pressure is correct and the
unit input rate is incorrect, check gas orifices for proper
size and restriction,
3 - Remove temporary gas meter if installed,
NOTE- To obtain accurate reading, shut off all other gas
appliances connected to meter.

Page 43

TABLE 12
Gas Flow Rate (Ft._/Hr.)
Seconds for 1
Gas Meter Size
Revolution
1/2 cu ft Dial
1 cu ft Dial
10
180
36O
12
150
30O
14
129
257
16
113
225
18
100
2OO
2O
9O
180
22
82
164
24
75
150
26
69
138
28
64
129
30
60
120
32
56
113
34
53
106
36
50
100
38
47
95
40
45
90
42
43
86
44
41
82
46
39
78
48
38
75
50
36
72
52
35
69
54
33
67
56
32
64
58
31
62
60
30
60

Manifold Pressure Measurement & Adjustment

• Attempts to clock gas meter during this procedure will
be inaccurate. Measure gas flow rate only during normal unit operation.

NOTE - Pressure test adapter kit (10L34) is available from
Lennox to facilitate manifold pressure measurement.

7 - When test is complete remove obstruction from hose
and return hose to gas valve barbed fitting,

1 - Connect test gauge to outlet tap on gas valve,
2 - Disconnect pressure sensing hose from gas valve,
3 - Start unit on low heat and allow 5 minutes for unit to
reach steady state.
4 - While waiting for the unit to stabilize, notice the flame.
Flame should be stable and should not lift from burner,
Natural gas should burn blue,

NOTE - In Canada, certification for installations at elevations over 4500 feet (1372 m) is the jurisdiction of local authorities.

5 - After allowing unit to stabilize for 5 minutes, record
manifold pressure and compare to value given in table
13.

The manifold pressure may require adjustment to ensure
proper operation at higher altitudes, Refer to table 13 for
proper manifold pressure settings at varying altitudes and
required pressure switch changes and conversion kits at
varying altitudes,

6 - Repeat steps 3, 4 and 5 on high heat,
NO TE - Shut unit off and remove manometer as soon as an
accurate reading has been obtained. Take care to replace
pressure tap plug.

The combustion air pressure switches are factory-set and
require no adjustment,

NOTE - During this test procedure, the unit will be oveffiring:

NOTE - A natural to L.P. propane gas changeover kit is
necessary to convert this unit. Refer to the changeover kit
installation instruction for the conversion procedure.

• Operate unit only long enough to obtain accurate reading to prevent overheating heat exchanger.

Conversion

TABLE 13
Kit Requirements and Manifold Pressures
Altitude

Model
Input
Size

0-4500 ft.
(0-1372 m)

Gas

Required
Conversion
Kit

Pressure
Switch

Manifold Pressure at all
altitudes

4501-7500 ft.
(1373-2286 m)
Required
Conversion
Kit

Pressure
Switch

7501-10,000
(2287-3048 m)
Required
Conversion
Kit

Low Fire

Pressure

in.

Switch

w.g.

kPa

High Fire
in.

kPa

w.g.

Nat

N/A

No Change

N/A

No Change

59M16

No Change

1.7

0.42

3.5

0.87

LPG

59M13

No Change

59M13

No Change

59M14

No Change

4.9

1.22

10.0

2.5

Nat

N/A

No Change

N/A

No Change

59M16

56M06

1.7

0.42

3.5

0.87

LPG

59M13

No Change

59M13

No Change

59M14

56M06

4.9

1.22

10.0

2.5

Nat

N/A

No Change

N/A

75M22

59M16

56M21

1.7

0.42

3.5

0.87

LPG

59M13

No Change

59M13

75M22

59M14

56M21

4.9

1.22

10.0

2.5

Nat

N/A

No Change

N/A

No Change

59M16

No Change

1.7

0.42

3.5

0.87

LPG

59M13

No Change

59M13

No Change

59M14

No Change

4.9

1.22

10.0

2.5

Nat

N/A

No Change

N/A

56M93

59M16

56M93

1.7

0.42

3.5

0.87

LPG

59M13

No Change

59M13

56M93

59M14

56M93

4.9

1.22

10.0

2.5

-045

-070

-090

-110

-135

Pressure switch is factory set. No adjustment necessary. All models use the factory installed pressure switch from 0-4500 feet (0-1370 m).

Page 44

Primary and Secondary Limits
The primary limit is located on the heating compartment
vestibule panel, The secondary limits are located in the
blower compartment, attached to the back side of the blower, These limits are factory set and require no adjustment,
Flame Rollout Switches

NO TE - Termination of any unused motor leads must be insulated.

(Two)

These manually reset switches are located on the burner
box, If tripped, check for adequate combustion air before
resetting,
Pressure Switches (Two or Four)
The pressure switches are located in the heating compartment on the combustion air inducer, These switches check
for proper combustion air inducer operation before allowing ignition trial, The switches are factory-set and require
no adjustment.
Back-Up Secondary

Limit (090, 110 & 135 Models)

The back-up secondary limit is located on the combustion
air inducer. This switch protects the plastic components
from overheating due to indoor blower motor failure, If
tripped, check for proper blower operation before resetting,
Temperature

Blower Speeds
NOTE - CFM readings are taken external to un# with a dry
evaporator coil and without accessories.
1 - Turn off electrical power to furnace,
2 - Remove blower access panel,
3 - Disconnect existing speed tap at control board speed
terminal.

Rise

After the furnace has been started and supply and return
air temperatures have been allowed to stabilize, check the
temperature rise, If necessary, adjust the blower speed to
maintain the temperature rise within the range shown on
the unit nameplate, Increase the blower speed to decrease
the temperature. Decrease the blower speed to increase
the temperature rise, Failure to do adjust the temperature
rise may cause erratic limit operation,
Thermostat Heat Anticipation
Set the heat anticipator setting (if adjustable) according to
the amp draw listed on the wiring diagram that is attached
to the unit.
Electrical
1 - Check all wiring for loose connections.
2 - Check for the correct voltage at the furnace (furnace
operating).
3 - Check amp-draw on the blower motor.
Motor Nameplate
Actual
NOTE - Do not secure the electrical conduit directly to the
air ducts or structure.

Page 45

4 - Refer to blower speed selection chart on unit wiring
diagram for desired heating or cooling speed.
5- Connect selected speed tap at control board speed
terminal.
6 - Resecure blower access panel.
7 - Turn on electrical power to furnace.
Electronic Ignition
The integrated control has an added feature of an internal
Watchguard control. The feature serves as an automatic
reset device for ignition control lockout caused by ignition
failure. This type of lockout is usually due to low gas line
pressure, After one hour of continuous thermostat demand
for heat, the Watchguard will break and remake thermostat
demand to the furnace and automatically reset the control
to begin the ignition sequence,
Exhaust and Air Intake Pipe
1 - Check exhaust and air intake connections for tightness
and to make sure there is no blockage,
2- Are pressure switches closed? Obstructed exhaust
pipe will cause unit to shut off at pressure switches.
Check termination for blockages,
3- Reset manual flame rollout switches on burner box
cover.
Failure To Operate
If the unit fails to operate, check the following:
1 - Is the thermostat calling for heat?
2 - Are access panels securely in place?
3 - Is the main disconnect switch closed?
4 - Is there a blown fuse?
5 - Is the filter dirty or plugged? Dirty or plugged filters will
cause the limit control to shut the unit off,
6
7
8
9

Is gas turned on at the meter?
Is the manual main shut-off valve open?
Is the internal manual shut-off valve open?
Is the unit ignition system in lock out? If the unit locks
out again, call the service technician to inspect the unit
for blockages,

Applications Using A Single-Stage Thermostat
NOTE - The thermostat selection DIP switch on the control
board is factory-set in the "TWO-STAGE" position.
Applications
Using a Two-Stage Thermostat
A - Heating Sequence -- Control Board Thermostat
Selection DIP switch in "Two-Stage" Position (Factory
Setting)
1 - On a call for heat, thermostat first-stage contacts close
sending a signal to the integrated control. The integrated control runs a self-diagnostic program and
checks high temperature limit switches for normally
closed contacts and pressure switches for normally
open contacts.The combustion air inducer is energized at low speed and the humidifier terminal is energized,
2- Once the control receives a signal that the low-fire
pressure switch has closed, the combustion air inducer begins a 15-second pre-purge in low speed.
3 - After the pre-purge is complete, a 20-second initial ignitor warm-up period begins. The combustion air inducer continues to operate at low speed.
4 - After the 20-second warm-up period has ended, the
gas valve is energized on low fire (first stage) and ignition occurs. At the same time, the control module
sends a signal to begin an indoor blower 45-second
ON-delay. When the delay ends, the indoor blower
motor is energized on the low fire heating speed. The
furnace will continue this operation as long as the thermostat has a first-stage heating demand.
5 - If second-stage heat is required, the thermostat second-stage heat contacts close and send a signal to the
integrated control. The integrated control initiates a
30-second second-stage recognition delay.
6 - At the end of the recognition delay, the integrated control energizes the combustion air inducer at high
speed. The control also checks the high-fire (second
stage) pressure switch to make sure it is closed. Once
the the control receives a signal that the high-fire pressure switch is close, the high-fire (second stage) gas
valve is energized and the indoor blower motor is energized for operation at the high-fire heating speed,
7 - When the demand for high-fire (second stage) heat is
satisfied, the combustion air inducer is switched to the
low-fire heating speed and the high-fire (second
stage) gas valve is de-energized. The low-fire (first
stage) gas valve continues operation. The indoor
blower motor is switched to the low-fire heating speed.
8 - When the thermostat demand for low-fire (first stage)
heat is satisfied, the gas valve is de-energized and the
field-selected indoor blower off delay begins. The
combustion air inducer begins a 5-second post-purge
period.
9 - When the combustion air post-purge period is complete, the inducer and humidifier terminal are de-energized. The indoor blower is de-energized at the end of
the off delay,

B - Heating Sequence -- Control Board Thermostat
Selection DIP switch in "Single-Stage"
Position
NOTE - In these application& two-stage heat will be initiated by the integrated control if heating demand has not
been satisfied after the field adjustable period (10 or 15
minutes).
1 - On a call for heat, thermostat first-stage contacts close
sending a signal to the integrated control. The integrated control runs a self-diagnostic program and
checks high temperature limit switches for normally
closed contacts and pressure switches for normally
open contacts.The combustion air inducer is energized at low speed and the humidifier terminal is energized.
2 - Once the control receives a signal that the low-fire
pressure switch has closed, the combustion air inducer begins a 15-second pre-purge in low speed.
3 - After the pre-purge is complete, a 20-second initial ignitor warm-up period begins. The combustion air inducer continues to operate at low speed,
4 - After the 20-second warm-up period has ended, the
gas valve is energized on low fire (first stage) and ignition occurs. At the same time, the control module
sends a signal to begin an indoor blower 45-second
ON-delay. When the delay ends, the indoor blower
motor is energized on the low-fire heating speed. The
integrated control also initiates a second-stage on
delay (factory-set at 10 minutes; adjustable to 15 minutes).
5 - If the heating demand continues beyond the secondstage on delay, the integrated control energizes the
combustion air inducer at high speed. The control also
checks the high-fire (second stage) pressure switch to
make sure it is closed. Once the control receives a signal the high-fire pressure switch is closed, the high-fire
(second stage) gas valve is energized and the indoor
blower motor is energized for operation at the high-fire
heating speed.
6 - When the thermostat heating demand is satisfied, thecombustion air inducer begins a 5-second post-purge,
The field-selected indoor blower off delay begins,
7- When the combustion air post-purge period is complete, the inducer and humidifier terminal are de-energized. The indoor blower is de-energized at the end of
the off delay,

Page 46

Cleaning Heat Exchanger
If cleaning the heat exchanger becomes necessary, follow
the below procedures and refer to figure 1 when disassembling unit. Use papers or protective covering in front of furnace while removing heat exchanger assembly.

,&WARNING

1 - Turn off electrical and gas supplies to the furnace.
2 - Remove the upper and lower furnace access panels.
3 - Mark all gas valve wires and disconnect them from
valve.
4 - Remove gas supply line connected to gas valve, Remove gas valve/manifold assembly,
5 - Remove sensor wire from sensor, Disconnect 2-pin
plug from the ignitor,
6 - Disconnect wires from flame roll-out switches.
7 - Remove burner box cover and remove four burner box

At the beginning of each heating season, system should be
checked as follows by a qualified service technician:
Blower
Check the blower wheel for debris and clean if necessary.
The blower motors are prelubricated for extended bearing
life, No further lubrication is needed,

screws at the vestibule panel and remove burner box,
Set burner box assembly aside,
NOTE - G61MP-135 units are secured to the vestibule
panel by two additional screws. These screws must be
removed for servicing; however it is not necessary to
replace the screws.
NOTE - If necessary, clean burners at this time. Follow
procedures outlined in Burner Cleaning section.
8 - Loosen three clamps and remove flexible exhaust tee,
9 - Remove 3/8 inch rubber cap from condensate drain
plug and drain, Replace cap after draining.
10 - Disconnect condensate drain line from the conden-

,&WARNING

sate trap, Remove condensate trap (it may be necessary to cut drain pipe), Remove screws that secure
condensate collars to either side of the furnace and remove collars, Remove drain tubes from cold end
header collector box.
Filters
All G61MP filters are installed external to the unit. Filters
should be inspected monthly. Clean or replace the filters
when necessary to ensure proper furnace operation, Table
3 lists recommended filter sizes,
Exhaust and air intake pipes
Check the exhaust and air intake pipes and all connections
for tightness and to make sure there is no blockage,
Electrical
1 - Check all wiring for loose connections.
2 - Check for the correct voltage at the furnace (furnace
operating),

11 - Disconnect condensate drain tubing from flue collar,
Remove screws that secure both flue collars into
place. Remove flue collars, It may be necessary to cut
the exiting exhaust pipe for removal of the fittings,
12 - Mark and disconnect all combustion air pressure tubing from cold end header collector box,
13 - Mark and remove wires from pressure switches. Remove pressure switches, Keep tubing attached to
pressure switches,
14 - Disconnect the 3-pin plug from the combustion air inducer, Disconnect the two wires to the backup secondary limit, if applicable. Remove four screws which secure combustion air inducer to collector box, Remove
combustion air inducer assembly,
wire from vest panel.

3 - Check amp-draw on the blower motor.
Motor Nameplate
Actual

Remove ground

15 - Remove electrical junction box from the side of the furnace.

Winterizing and Condensate Trap Care
1 - Turn off power to the unit,
2 - Have a shallow pan ready to empty condensate water.
3 - Remove the drain plug from the condensate trap and
empty water, Inspect the trap then reinstall the drain
plug,

Page 47

16 - Mark and disconnect any remaining wiring to heating
compartment components. Disengage strain relief
bushing and pull wiring and bushing through the hole
in the blower deck.
17 - Remove the primary limit from the vestibule panel.

18- Removetwoscrewsfromthefrontcabinetflangeat
theblowerdeck.Spreadcabinetsidesslightlytoallow
clearance
forremovalofheatexchanger,
19- Removescrewsalongvestibulesidesand bottom
whichsecurevestibulepanelandheatexchanger
assemblyto cabinet.Removetwoscrewsfromblower
railwhichsecurebottomheatexchanger
flange,Removeheatexchanger
fromfurnacecabinet,
20- Backwashheatexchanger
withsoapywatersolution
or steam,If steamis usedit mustbe below275°F
(135°C).

assembly.
22 - Reinstall heat exchanger into cabinet making sure that
the clamshells of the heat exchanger assembly are
resting on the support located at the rear of the cabinet. Remove the indoor blower to view this area
through the blower opening,
23 - Re-secure the supporting screws along the vestibule
sides and bottom to the cabinet,
24- Reinstall cabinet screws on front flange at blower
deck.
25 - Reinstall the primary limit on the vestibule panel.
26 - Route heating component wiring through hole in blower deck and reinsert strain relief bushing,
27 - Reinstall electrical junction box,
28 - Reinstall the combustion air inducer. Reconnect the
3-pin plug to the wire harness, Reconnect the two
wires to the backup secondary limit, if applicable,
29 - Reinstall pressure switches and reconnect pressure
switch wiring.
30 - Carefully connect combustion air pressure switch hosing from pressure switches to proper stubs on cold end
header collector box,

32 - Reinstall condensate trap on same side as exhaust
pipe, Reconnect condensate drain line to the condensate trap.
33 - Use securing screws to reinstall flue collars to either
side of the furnace. Reconnect exhaust piping and exhaust drain tubing.

39- Reinstall gas valve manifold assembly,
gas supply line to gas valve,
40 - Reinstall burner box cover,

Reconnect

41 - Reconnect wires to gas valve.
42 - Replace the blower compartment

access panel,

43 - Refer to instruction on verifying gas and electrical connections when re-establishing supplies.
44- Follow lighting instructions to light and operate furnace for 5 minutes to ensure that heat exchanger is
clean and dry and that furnace is operating properly,

21 - Thoroughly rinse and drain the heat exchanger. Soap
solutions can be corrosive, Take care to rinse entire

31 - Reinstall condensate collars on each side of the furnace. Reconnect drain tubing to collector box,

38 - Secure burner box assembly to vestibule panel using
four existing screws. Make sure burners line up in
center of burner ports.

45 - Replace heating compartment access panel,
Cleaning the Burner Assembly
1 - Turn off electrical and gas power supplies to furnace,
Remove upper and lower furnace access panels,
2 - Mark all gas valve wires and disconnect them from the
valve,
3 - Disconnect the gas supply line from the gas valve, Remove gas valve/manifold assembly,
4 - Mark and disconnect sensor wire from the sensor. Disconnect 2-pin plug from the ignitor at the burner box.
5 - Remove burner box cover and remove four screws
which secure burner box assembly to vest panel, Remove burner box from the unit.
NOTE - G61MP-135 units are secured to the vestibule
panel by two additional screws. These screws must be
removed for servicing; however it is not necessary to
replace the screws.
6 - Use the soft brush attachment on a vacuum cleaner to
gently clean the face of the burners, Visually inspect
the inside d the burners and crossovers for any blockage caused by foreign matter, Remove any blockage.
7 - Reconnect the sensor wire and reconnect the 2-pin
plug to the ignitor wiring harness.
8 - Reinstall the burner box assembly using the existing
four screws. Make sure that the burners line up in the
center of the burner ports.
9 - Reinstall the gas valve manifold assembly, Reconnect
the gas supply line to the gas valve, Reinstall the burner box cover,
10 - Reconnect the gas valve wires to the gas valve.

34 - Replace flexible exhaust tee on combustion air inducer and flue collars, Secure using three existing hose
clamps,

11 - Replace the blower compartment access panel.

35 - Reinstall burner box assembly in vestibule area,
36 - Reconnect flame roll-out switch wires,

13- Follow lighting instructions to light and operate furnace for 5 minutes to ensure that heat exchanger is
clean and dry and that furnace is operating properly,

37 - Reconnect sensor wire and reconnect 2-pin plug from
ignitor,

12 - Refer to instruction on verifying gas and electrical connections when re-establishing supplies.

14 - Replace heating compartment access panel,

Page 48

FLASH CODE

(x. Y)

STATUS / ERROR DESCRIPTION
FLASH

CODE DESCRIPTIONS

Pulse

A 1/4 second flash followed by four seconds of off time.

Heartbeat

Constant 1/2 second bright and 1/2 second dim cycles.

X+Y
Pulse
Heartbeat

LED flashes X times at 2Hz, remains off for two seconds, flashes Y times at 2Hz, remains off for four
seconds,

then repeats.

Power on - Standby.
Normal operation

- signaled

when

heating

FLAME

demand initiated at thermostat.
CODES

1+2
1+3

t Flame
Low flame
current
---run
modem-- flame still present.
sensed
out of
sequence
PRESSURE SWITCH CODES

2+3

Low pressure switch failed open.

2+4

Low pressure switch failed closed.

2+5

High pressure switch failed open.

2+6
2+7

High pressure switch failed closed.
Low pressure switch opened during ignition trial or heating demand.
LIMIT CODE

3+1

Limit switch open.
WATCI-IGUARD

CODES

4+1

Watchguard -- Exceeded maximum number of retries.

4+2

Watchguard -- Exceeded maximum number of retries or last retry was due to pressure switch opening.

4+3

Watchguard -- Exceeded maximum number of retries or last retry was due to flame failure.

4+5

Watchguard -- Limit remained open longer than three minutes.

4+6
4+7

Watchguard -- Flame sensed out of sequence; flame signal gone.
Ignitor circuit fault -- Failed ignitor or triggering circuitry.

4+8

Low line voltage.
HARD LOCKOUT

CODES

5+1

Hard lockout -- Rollout circuit open or previously opened.

5+2

Control failed self check, internal error (control will restart if error recovers).

5+3
5+4

No Earth ground (control will restart if error recovers).
Reversed line voltage polarity (control will restart if the error recovers).

5+6

Low secondary (24VAC) voltage.

Error Code Storage
The ignition control stores the last ten error codes in
memory, The codes are retained in case of power loss.
Error Code Review
1 - Short R (2) to (1). Within 1/2 second, the STATUS LED
will stay lit continuously to indicate that the short was
sensed.
2 - Continue to hold the short between R (2) to (1). After 5
seconds, STATUS LED will go from being continuously lit to off. This indicates that error code review is pending.

5 - After final error code is indicated, STATUS LED will
flash to indicate normal operation.
Clearing

Error Codes

1 - Short R (2) to (1). Within 1/2 second, the STATUS LED
will stay lit continuously to indicate that the short was
sensed.
2 - Continue to hold the short between R (2) to (1). After 5
seconds, STATUS LED will go from being continuously lit to off,
3 - Continue to hold the short between R (2) to (1) beyond
ten seconds after STATUS LED has turned off. STA-

3 - Remove R (2) to (1) short within ten seconds of STATUS LED turning off, This activates error code review.

TUS LED will turn on, indicating that error codes have
been cleared,

4 - Last ten error codes will be flashed on the STATUS
LED.

4 - Remove R (2) to (1) short. STATUS LED will flash to
indicate normal operation.

Page 49

HEATING SEQUENCE OF OPERATION
NORMAL AND ABNORMAL HEATING MODE
I

POWER ON

CONTROL SELF-CHECK

OKAY?

POLARITY OKAY?

YES
IS THERE A
PROPER GROUND?

INDOOR BLOWER OFF. (RESET CONTROL BY
VALVETURNING
OFF. COMBUSTION
AIROFF.)
INDUCER OFF.
MAIN POWER

I_GAS

STATUS
ERROR
CODE 5 + 4.
POLARITY
REVERSED.

STATUS
5 + 3. GROUNDED.
HOLDS
UNTIL ERROR
UNIT IS CODE
PROPERLY

__SlGNAL

YES

_
A
NORMAL OPERATION:
STATUS LED -- PULSE

/
COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER ON. HAS PRIMARY OR
SECONDARY LIMIT RESET WITHIN 3 MINUTES?
STATUS ERROR CODE 3 + 1.

B
THERMOSTAT CALLS FOR HEAT:
STATUS LED -- HEARTBEAT

YES
PRIMARY AND SECONDARY

LIMIT

SWITCHESyEs
_LOSED?

YES

FIRST (LOW) STAGE PRESSURE SWITCH
CONTACTS OPEN?
YES

SECOND

(HIGH)
CONTACTS
STAGE PRESSURE
OPEN?

YES
r
I TWO-STAGE
IL

60-MINUTE LIMIT WATCHGUARD MODE.
GAS VALVE OFF, COMBUSTION AIR INDUCER
OFF, INDOOR BLOWER OFF WITH DELAY.
STATUS ERROR CODE 4 + 5.
GAS VALVE OFF. COMBUSTION AIR INDUCER ON.
INDOOR BLOWER ON.
STATUS ERROR CODE 5 + 1.
SEQUENCE HOLDS UNTIL ROLLOUT SWITCH IS
RESET AND MAIN POWER IS INTERRUPTED OR
T'STAT IS CYCLED OFF/ON FOR 3 SEC. MINIMUM.

ROLLOUT SWITCH CLOSED?

GAS VALVE OFF. COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER OFF. CONTROL REMAINS UNTIL
PRESSURE SWITCH IS DETECTED OPEN.
STATUS ERROR CODE 2 + 4

SWITCH

_
1

OR SINGLE-STAGE
CALL FOR HEAT

THERMOSTAT

COMBUSTION
AIRLED
INDUCER
ON LOW SPEED.
STATUS
-- HEARTBEAT

GAS VALVE OFF.
COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER OFF.
CONTROL WILL NOT ATTEMPT SECOND-STAGE
OPERATION DURING THIS HEAT DEMAND.
FIRST-STAGE OPERATION WILL BE ATTEMPTED.
STATUS ERROR CODE 2 + 6.

CONTINUED ON NEXT PAGE

Page 50

YES

HEATING SEQUENCE OF OPERATION
CONTINUED

THERMOSTAT CALLS FOR HEAT
STATUS LED - HEARTBEAT.
(Refer to box A on previous page)
NO

FIRST-STAGE
(LOW
F,RE)PRESSURE
I

SWITCH CLOSED WITHIN 2.5 MINUTES?
YES

OFF. INDOOR BLOWER OFF. UNIT WILL RETRY
AFTER 5-MINUTE WAIT PERIOD,
GAS VALVE
OFF. ERROR
COMBUSTION
STATUS
CODE 2AIR
+ 3.INDUCER

_
m

15-SECOND COMBUSTION AIR INDUCER
PRE-PURGE INITIATED BY CLOSED
FIRST-STAGE PRESSURE SWITCH (or 15
SECOND INTER-PURGE PERIOD.)
STATUS LED -- HEARTBEAT.

[

IGNITOR
STATUS
WARM-UP
LED -- HEARTBEAT.
I_0
SECONDStJ
YES

NO
is IGNITOR INTACT AND CONNECTED?

SIGNAL HOLDS UNTIL IGNITOR IS REPLACED OR
RECONNECTED,
COMBUSTION AIR
INDUCER OFF, IGNITOR OFF.
STATUS ERROR CODE 4 + 7.

YES

PERIOD, 4-SECOND TRIAL FOR IGNITION.
I
GAS VALVE OPENS, IGNITOR ENERGIZED DURING
I
AT END OF IGNITOR 20 SECOND WARM UP
I
4-SECOND TR AL UNT L FLAME SENSED,

---4

IS VOLTAGE ABOVE 90 VOLTS?

.o_

YES
I

4-SECOND

FLAME STABILIZATION

PERIOD.

COMBUSTION AIR INDUCER OFF, IGNITER OFF.
SIGNAL HOLDS UNTIL VOLTAGE RISES ABOVE 95
VOLTS, STATUS ERROR CODE 4 + 8.

CAN FLAME BE PROVEN WITHIN 4
SECONDS AFTER GAS VALVE OPENS?
FLAME RECTIFICATION CURRENT CHECK
( > 0.20 microamps)

GAS VALVE OFF. COMBUSTION AIR
INDUCER ON. INDOOR BLOWER OFF.
STATUS LED -- HEARTBEAT,
HAS CONTROL FAILED TO SENSE
FLAME FOR FIVE CONSECUTIVE TRIES
DURING A SINGLE HEAT DEMAND?

Iql

YES lr
WATCHGUARD MODE, GAS VALVE OFF,
COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER OFF.
STATUS ERROR CODE 4 + 1.
IS 60-MINUTE RESET PERIOD COMPLETE?

YES

FLAME PRESENT?

IN'-_-_°

HAS CONTROL

RESET IGNITION SEQUENCE
FOUR (4) TIMES?
WATCHGUARD MODE,
STATUS ERROR CODE 4 + 3.

YES

[

CONTINUED ON NEXT PAGE

Page 51

HEATING SEQUENCE OF OPERATION
CONTINUED

THERMOSTAT CALLS FOR HEAT.
STATUS LED -- HEARTBEAT.
SEE BOX A.

LOW FLAME SIGNAL
affect control
(Does not
operation)
STATUS ERROR CODE 1 + 2.

FLAME SIGNAL ABOVE
( > 1.40 microamps)
YES 1

YES
[---_

I SINGLE-STAGE THERMOSTAT MODE
'L
(DIP SWITCH SET AT 'SINGLE")

I
I'

(DIP SWITCH SET AT 'TWO")

YES _
]

SWITCHES

I
I

45-SECOND STATUS
INDOOR LED
BLOWER
-- HEARTBEAT.
ON DELAY BEGINS.]

CLOSED?

F-

GAS VALVE OFF. COMBUSTION AIR INDUCER ON.
INDOOR BLOWER ON.
STATUS ERROR CODE 5 + 1. SEQUENCE HOLDS
UNTIL ROLLOUT SWITCH IS RESETAND MAIN
POWER IS INTERRUPTED OR THERMOSTAT
IS CYCLED OFF/ON FOR 3 SECOND MINIMUM.

YES
,!
FIRST-STAGE

HEAT DEMAND SATISFIED?

OFF, INDOOR BLOWER ON.
GAS VALVE
OFF, ERROR
COMBUSTION
STATUS
CODE 3AIR
+ 1.INDUCER

YES

GAS VALVE OFF, COMBUSTION AIR INDUCER
OFF FOLLOWING POST PURGE.
INDOOR BLOWER OFF WITH DELAY
STATUS LED -- PULSE

NO _I

YES _

SECOND-STAGE 30-SECOND DELAY ON BEGINSJ
STATUS LED -- HEARTBEAT.
YES _
SECOND-STAGE
COMBUSTION AIR INDUCER
ON. SECOND-STAGE
GAS VALVE ON. HIGH
HEAT INDOOR BLOWER SPEED ON.
STATUS LED -- HEARTBEAT.

YES
SECOND-STAGE

PRESSURE

SWITCH CLOSED

IN LESS THAN TEN (10) SECONDS?
STATUS LED -- HEARTBEAT

NO1,

SECOND-STAGE
SECOND-STAGE
HEAT DEMAND
HEAT DEMAND.
REQUIRED?

ABNORMAL FLASH CODE.
NOTE - IF SECOND-STAGE PRESSURE SWITCH
SECOND
WASSTAGE
ORIGINALLY
PRESSURE
FOUND
SWITCH
CLOSED,
CLOSED?
ABNORMAL CODE WILL FLASH.

HAS PRIMARY OR SECONDARY LIMIT
SWITCH CLOSED WITHIN 3 MINUTES?
(Indoor blower on low speed during 3-minute period)

LIMIT SWITCH WATCHGUARD MODE.
GAS VALVE OFF, COMBUSTION AIR INDUCER OFF

YES _

PRIMARY & SECONDARY LIMIT SWITCHES
CLOSED?
ROLLOUT

PRESSURE
FIRST-STAGE
SWITCH
(LOWCLOSED?
FIRE)

YES

I'I1"_

YES _

START SECOND-STAGE
RECOGNITION
ON DELAY (10 OR 15 MINUTES).
STATUS LED -- HEARTBEAT

INDOOR BLOWER OFF WITH DELAY.
STATUS ERROR CODE 4 + 5
IS 60-MINUTE RESET PERIOD COMPLETE?

.Y.E,£_

.._1.1 GAS VALVE OFF. COMBUSTION AIR INDUCER ON.
|
INDOOR BLOWER OFF AFTER DELAY.
| STATUS ERROR CODE 2 + 3. CONTROL RESTARTS
|
IGNITION SEQUENCE IF PRESSURE SWITCH
/
CLOSES WITHIN 2-1/2 MINUTES.
_1"

YES

SECOND-STAGE PRESSURE SWITCH CLOSED
AT BEGINNING OF HEAT DEMAND?
STATUS ERROR CODE 2 + 6.

SECOND STAGE HEAT DEMAND
STATUS LED -- HEARTBEAT.

NO
RETURNS TO FIRST-STAGE HEAT MODE WHICH
CONTINUES UNTIL SECOND-STAGE PRESSURE
SWITCH CAN BE PROVEN or HEAT DEMAND IS
SATISFIED. FIVE (5) MINUTE WAIT PERIOD
INITIATED BEFORE RETRY. WERE 5 ATTEMPTS
MADE FOR SECOND-STAGE HEAT?
YES
CONTINUES FIRST-STAGE HEATING
DEMAND. WILL NOT REATTEMPT
SECOND-STAGE
HEATING DEMAND.
STATUS ERROR CODE 2 + 5.

YES _

CONTINUED ON NEXT PAGE

Page 52

HEATING SEQUENCE OF OPERATION
CONTINUED

SEE BOX A
NORMAL OPERATION.

SEE BOX B
THERMOSTAT CALLS FOR HEAT.

RETURN TO FIRST-STAGE HEAT MODE.
FIRST-STAGE CONTINUES UNTIL SECONDSTAGE PRESSURE SWITCH CAN BE PROVEN

SECOND-STAGE
(HIGH FIRE) HEAT
PRESSURE SWITCH CLOSED?

or HEAT DEMAND IS SATISFIED. A FIVE (5)
MINUTE WAIT PERIOD IS INITIATED BEFORE
RETRY. WERE 5 ATTEMPTS MADE FOR

NO
YES _

HEAT DEMAND SATISFIED?
STATUS LED -- HEARTBEAT.

YES

[
L

SINGLE-STAGE THERMOSTAT MODE
(DIP SWITCH SET AT "SINGLE")

I '

TWO STAGE THERMOSTAT MODE?
(DIP SWITCH SET AT "TWO")

1,
I
J

YES'f

YES I
GAS VALVE OFF, COMBUSTION AIR
INDUCER OFF AFTER 5-SECOND
LOW SPEED POST PURGE PERIOD,
INDOOR BLOWER OFF DELAY
INITIATED ON LOW HEAT SPEED.
STATUS LED -- HEARTBEAT.

SECOND-STIAGE HEAT?
NO '_
SEE BOX C
FIRST-STAGE HEAT DEMAND SATISFIED?

I, _[
I

FIRST AND SECOND

Y/-_b

_,_J

I-

STAGE HEAT

DEMAND SATISFIED SIMULTANEOUSLY.

I,,_

DEMANDSECOND
SASTISFIED?STAGE
HEAT
STATUS LED -- HEARTBEAT.

STATUS LED -- HEARTBEAT.

YES
AND INDOOR BLOWER RETURN TO FIRSTSTAGE OPERATION.
GAS VALVE, COMBUSTION AIR INDUCER
STATUS LED -- HEARTBEAT.

FIRST STAGE HEAT DEMAND SATISFIED?
YES

DEMAND FOR HEAT SATISFIED.
POWER ON STAND BY.
STATUS LED -- PULSE.

OFF AFTER 5-SECOND LOW SPEED POSTPURGE PERIOD. INDOOR BLOWER OFF.
GAS VALVE OFF. COMBUSTION AIR INDUCER
DELAY INITIATED ON LOW HEAT SPEED.
STATUS LED -- PULSE.

Page 53

COOLING
SEQUENCE
OF OPERATION
I

POWER ON

IS POLARITY

I
SIGNAL POLARITY REVERSED.
CONTROL WILL CONTINUE TO CALL FOR COOLING
IN THIS CONDITION,
STATUS ERROR CODE 5 + 4.

REVERSED?

I PROPER
IS THERE
GROUND?

CONTROL WILL CONTINUE TO CALL FOR COOLING
IN THIS CONDITION,
SIGNAL IMPROPER GROUND AT LED.
STATUS ERROR CODE 5 + 3.

_ YES

THERMOSTAT

CALLS FOR FIRST-STAGE

COOL.

4,
COMPRESSOR AND CONDENSER
ENERGIZED.

FAN

4,
INDOOR BLOWER ENERGIZED ON FIRST STAGE
COOL SPEED AFTER 2 SECOND DELAY,

FIRST-STAGE

DEMAND FOR COOL SATISFIED?

COMPRESSOR
AND BLOWER
CONDENSER
FAN DE-ENERGIZED.
NDOOR
DE-ENEG
ZED.

Nol

ITHERMOSTATOALLS
FORSEOOND-STAGE
COOL.
I

I ,NDOOR
BLOWER
RAMPS
UP
TO
SECOND-STAGE
COOL
SPEED.
I
SECOND-STAGE

DEMAND FOR COOL SATISFIED?

YES

-_1

o.,_o_.s_o_,_s_s_A_COO.
I

Page 54

CONTINUOUS
LOW

SPEED FAN SEQUENCE OF OPERATION

MANUAL FAN SELECTION MADE AT THERMOSTAT.
AFTER 2 SECOND DELAY, INDOOR BLOWER IS
ENERGIZED ON CONTINUOUS FAN SPEED,
YES

THERMOSTAT

CALLS FOR FIRST STAGE

COOL.

YES

THERMOSTAT

CALLS FOR FIRST-STAGE

YES
I

COOLING
A 2-SECOND
DELAY,
INDOOR SPEED
BLOWERAFTER
RAMPS
TO FIRST STAGE

FIRST-STAGE

YES

LOW HEAT
SPEED,
AFTERSWITCHES
45-SECONDTO DELAY,
INDOOR
BLOWER

COOL DEMAND SATISFIED?

NO_
SECOND
STAGE
COOL
DEMAND

HEAT.

FIRST-STAGE

HEAT DEMAND SATISFIED.

_YI

NO
I

THERMOSTAT

CALLS FOR SECOND-STAGE

HEAT.

YES ,_
I

INDOOR BLOWER
RAMPS
TO SECOND
STAGE COOL
SPEED

INDOOR
BLOWER
SWITCHES
TO HIGH HEAT
SPEED
AFTER
30-SECOND
RECOGNITION
PERIOD.

YES ,_

SECOND
STAGE
COOL
DEMAND
SAT,SFED?I I

SECOND-STAGE

YES

HEAT DEMAND SATISFIED.

YES

I 'NDOOR
BLOWER
RAMPS
_cooL
SPEED
DOWN
TO
F'RST
STAGE
I

INDOOR BLOWERHEATRAMPSsPEED.DOWN
TO LOW

The following repair parts are available through Lennox dealers, When ordering parts, include the complete furnace model
number listed on the CSA nameplate -- Example: G61MP-36B-045-1,
Cabinet Parts

Heating Parts

Upper access panel
Blower access panel
Top Cap
Control Panel Parts
Transformer

Flame Sensor
Heat exchanger assembly
Gas manifold
Combustion air inducer
Gas valve
Main burner cluster
Main burner orifices
Pressure switches

Two-stage integrated control board
Door interlock switch
Circuit Breaker
Blower Parts

Ignitor
Primary limit control
Secondary limit control
Flame rollout switches

Blower wheel
Motor
Motor mounting frame
Motor capacitor
Blower housing cutoff plate

Combustion air inducer auxiliary limit

Page 55

Step 1

Proposed

vent pipe size :

Equivalent

Step 2

Termination
kit catalog number :
Vent pipe equivalency
value from table 5 :

Step 3

Total number of 90 ° elbows required (indoors
X 5 =
equivalent feet of pipe

and outdoors)

Step 4

Total number of 45 ° elbows required (indoors
X 2.5 =
equivalent feet of pipe

and outdoors)

Step 5

Linear feet of straight

Step 6

Add equivalent feet of vent pipe listed in
steps 2 through 5.

pipe required

Feet

:
TOTAL

If the total is equal to, or less than, the allowable
maximum given in table 6, the proposed
pipe size is acceptable.
If the
total exceeds the maximum
allowed vent pipe length, repeat the process above using the next larger diameter pipe until
an acceptable
total is achieved.
NOTE - In Direct Vent systems, total the equivalent length of either the exhaust OR intake piping run, depending upon which
will be LONGER.
Intake and exhaust pipe diameter must be the same size and must be terminated
in the same pressure
zone. Intake and exhaust pipe should be roughly the same length.

Job Name

Job No.

Date

Job Location

City

State

Installer

City

State

Unit Model No.

Technician

Serial No.
Heating

Section

[]

Electrical Connections Tight?
Line Voltage

Blower Motor H,P.

Blower Motor Amps

Gas Piping Connections
Tight & Leak-Tested?

Fuel Type: Natural Gas?

[]

LP/Propane Gas?

[]

_ Line Pressure

Furnace Btu Input (High fire)
Low Fire Manifold Pressure

w.c, - Nat,:

High Fire Manifold Pressure

w.c. - Nat,:

[]

Flue Connections Tight?

Combustion Gas Tested (high fire and low fire)?

w,c, - LP/Propane
__

w,c, - LP/Propane
Proper Draft?

[] co2

[]

[] co

External Static Pressure?
(0.5 maximum)

Blower ON delay confirmed?
(45 Seconds Fixed On)

Temperature

Blower OFF Delay Setting (60, 90, 120 or 180)?
Filter Clean & Secure?

Rise

[]

Thermostat
Heat Anticipator Setting?

Thermostat Level? []

Page 56

Source Exif Data:

File Type                       : PDF
File Type Extension             : pdf
MIME Type                       : application/pdf
PDF Version                     : 1.2
Linearized                      : No
Page Count                      : 56
Page Layout                     : SinglePage
Page Mode                       : UseNone
Producer                        : Goby Monitor Application version 4, 0, 0, 13
Create Date                     : Mon Jun 30 04:43:27 2008
Author                          : 
Title                           : 
Subject                         :

EXIF Metadata provided by EXIF.tools

LENNOX Furnace/Heater, Gas Manual L0806204

Navigation menu

Versions of this User Manual:

Views

Navigation