LENNOX Furnace/Heater, Gas Manual L0406249

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

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LENNDX

INSTALLATION
INSTRUCTIONS

G26 SERIES UNITS
Technical

GAS UNITS
504,228M
11/2000
Supersedes 503,885M

_Publications
Litho U.S.A.

Unit Dimensions ...............................
G26 Parts Identification .........................
Requirements ..................................
General .......................................
Installation - Setting Equipment ..................
Return Air Opening Guidelines ...................
Filters & Optional Filter Assembly ................
Duct System ...................................
Pipe & Fittings Specifications ....................
Vent Piping Guidelines ..........................
Joint Cementing Procedure ......................
Venting Practices ...............................
Gas Piping ...................................
Electrical .....................................
Unit Start-Up .................................
Gas Pressure Adjustment ......................
High Altitude Information .......................
Other Unit Adjustments ........................
Service ......................................
Repair Parts ..................................
Troubleshooting ...............................
Start-Up & Performance Check List ..............
RETAIN
THESE INSTRUCTIONS
FOR FUTURE
REFERENCE

2
3
4
4
5
5
6
7
7
8
8
9
15
16
20
21
22
22
23
26
26
31

WHAT TO DO IF YOU SMELL GAS:
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.

• Do not W to light any appliance.
• Extinguish any open flames.
• Do not touch any electrical switch; do not use
any phone in your building.
• 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.

11/00

I|UUWIIMLIII

504,228M
Page1

IIIHIIlUlIIIIIgIIHIII

35/8 (92) _
l

.L 1 1/16
T
(41)

,
_I/

1 1116
(41)

5/8
116)-I P _'_

2_-_
25 (635)

EXHAUST

(51)

AIR OUTLET

TOP VIEW
qlm

A -_---I_

(724)

'T T

21 3/4
(552)

/mmr

46
(1168)

(684)

DRNN

EXTERNAL
SIDERE'RJRN
AIR RL'I-r.RKIT
ELECTRICAL
INLET
(Both Sides)

_--23

(Bth_S_e)
(opeo._ ,

GAS PIPING
INLET
(Both sides)

t
AiR FLOW

4 (102)

(584) --_

I
L_

RETURN
(Either Side)
AIR_
KNOCKOUT

,1-15/18(,,)
I
L

23 (584)
Return Air
Knockout (Bottom)

5/8(
E-I'

4(102)

Return Air
Knockout (Bottom)

SIDE VIEW

FRONT VIEW

A
Model No,

In,

in.

In.

in.

In.

in.

In.

G26Q2-5O
G26Q3-50
G26Q3-75

16-1/4

413

14-1/8

359

305

2-1/8

7-5/8

194

356

12-314

324

G26Q3/4-100
G26Q4/5-75
G26Q4/5-100

21-1/4

540

19-1/8

486

457

; 457

1-5/8

10-1/8

257

508

18-3/4

476

26-114

667

24-1/8

613

457

4-1/8

105

12-5/8

321

508

18-3/4

476

G26Q3/4-125
G26Q4/5-125

Page 2

G26 Pa_

n gement

....

, _,

G26 PARTS IDENTIFICATION

GLASS FIBER GASKET
FLUE COLLAR
FRESH AIR
INTAKE FITTING

BURNER BOX
ASSEMBLY

_."

WARM
HEADER
(COLLECTOR)
BOX

PATCH

PATCH PLATE WITH
BARBED FITTING
AND FLAME
ROLL-OUT SWITCH
DuralokPlus TM
HEAT EXCHANGER
ASSEMBLY

GLASS
BURNER
BOX
COVER

CABINET

FLUE
TRANSITIO

PROVE
(PRESSURE)
SWITCH

GAS VALVE AND
MANIFOLD

SUPPLY
AIR
BLOWER

BURNER
ACCESS
PANEL
PRIMARY LIMIT
(ALTERNATE STYLES)
COIL
TRANSFORMER
CONTROL VOLTAGE
CIRCUIT BREAKER

BLOWER
ACCESS
DOOR

J
COMBUSTION
ORIFICE

DOOR INTERLOCK SWITCH
AIR

CONTROL BOX COVER

COLD HEADER
(COLLECTOR)
BOX
COMBUSTION
INDUCER

AIR

FIGURE 1

Page 3

The fumace must be adjusted to obtain a temperature dse
within the range specified on the unit rating plate.

All G26 units

are CSA International certified to ANSI
Z21.47 and CSA 2.3 standards.
In the USA, installation of Lennox gas central fumaces must
conform with local building codes. In the absence of local
codes, units must be installed according to the current National Fuel Gas Code (ANSI-Z223.1) in the United States.
The National Fuel Gas Code is available from the following
address:

When installed, the furnace must be electrically grounde_:
according to local codes. In addition, in the United States
installation must conform with the current National Electric
Code, ANSI/NFPA No. 70. The National Electric Code
(ANSI/NFPA
dress:

No. 70) is available from the following adNational Fire Protection Association
1 Battery March Park
Quincy, MA 02269

American National Standards Institute, Inc.
11 West 42nd Street
New York, NY 10036
In Canada, installation must conform with current National
Standard of Canada CAN/CGA-B149.1 "Installation Code
for Natural Gas Burning Appliances and Equipment" and
CAN/CGA-B149.2 "Installation Code for Propane Gas
Burning Appliances and Equipment," local plumbing or
waste water codes and other applicable local codes.
Adequate clearance must be made around the air openings into the vestibule area. Provisions must be made for

Wiring to be done in the field, between the furnace and devices not attached to the furnace or between separate devices which are field-installed and located, shall conform
with the temperature limitation for type T wire [63°F (17°C)
rise] when installed in accordance with these instructions.
G26 unit must be installed so that electrical components
are protected from water.
When the furnace is installed so that supply ducts carry air
circulated by the furnace to areas outside of the space containing the furnace, return air shall be handled by a duct(s)
sealed to the fumaca casing and terminating out-side
space containing furnace.

proper operation and for combustion air and ventilation air
supply according to the current National Fuel Gas Code or
CAN/CGA-B149 standards.
This fumaca is CSA Intemational certified for installation
clearances to combustible matedal as listed on the unit rating
plate and in table 1.
TABLE 1
Clearances

Location

Inches (ram)

Front

24 (610)

Service access
Condensate

side

41 WARNING

3 (76)
(fromside of unit)

Top

1 (25)

To combustible

Exhaust

materials

Side, rear, and front

Flnor

*Appliance shall not be installed directly on carpeting, tile or other combustible material other than wood flooring.
NOTE-Service access clearance mum be rnaintalee_

NOTE - For installation on combustible floors, the fumace shall
not be installed directlyon carpeting, bTe,or o_er combustible
material other than wood flooring.
Accessibility and service clearances must take precedence over fire protection clearances.
For installation in a residential garage, the fumace must be
installed so that the bumer(s) and the ignitionsource are located no less than 18 inches (457 mm) above the floor. The
furnace must be located or protected to avoid physical damage by vehicles.When a fumace is installedin a publicgarage,
hangar, or other buildingthat has a hazardous atmosphere,
the fumaca must be installed according to recommended
good practice requirements and current Na'donalFuel Gas
Code or CAN/CC_ B149.1 and B149.2 standards.

NOTE - G26 series units must not be used as a construction heater during any phase of construction. Very low return air temperatures, harmful vapors and misplacement of
the filters will damage the unit and lower its efficiency.

These inslructJons
are intendedas a general guide and do not_
supersede local codes in any way. Consult authoritieshavir_
judsdic_onbefore installation.

Page 4

Shipping and Packing List
1 - Assembled G26 furnace
1 - Bag assembly containing
1 - Electrical make-up box
1 - Wiring harness
1 - Snap bushing
2 - Filter clips
1 - 3 inch x 2 inch vent transitionpiece (-100, -125 units
only)
1 - Adapter
1 - Condensate plug
1
1
1
3

WARNING

Nipple
Brown accessory wire
Green ground wire
Wire nuts

2 - Star washers
Shipping Damage
Check equipment for shipping damage. If you find any
damage, immediately contact the last carrier,

WARNING

Return air can be brought in either side or at the bottom of
the unit. Scribe lines show the outline of each side and the
bottom return air opening.
Bottom Return Air Applications
If cold air return is to terminate through the floor under the
furnace, a direct, airtight and sealed connection must be
made to the bottom of the furnace.

Select a location that allows for required clearances
listed on the unit rating plate. Also consider gas supply
connections, electrical supply, vent connection and
installation and service clearances [24 inches (610 mm)
at unit front]. The furnace must be level.
NOTE - 1/3 and 1/2 hp blower motors are equipped with either four flexible mounting legs or 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 w#h a flexible mounting leg). This
shipping bolt and flat washer must be removed before the
furnace is put into operation. Once the shipping bolt and
washer are removed, the rigid leg will not touch the blower
housing.

1 - Cut opening in floor or platform. Using knockouts provided, cut bottom of base panel. See figure 2.
KNOCKOUT PATTERN FOR BOTTOM
RETURN AIR APPLICATION

tv
FIGURE 2
2 - Bend a flange on return air plenum and lower into floor

CAUTION

or platform opening. See figure 3.
3 - Position unit over return air opening. Seal unit air tight
with return air plenum.

Page 5

BOTTOM RETURN AIR APPLICATION

Side Retum Air Applications
An external filter rack, ordered separately, is available from
Lennox.
NOTE - The filter door may be shipped in the rack behind
the filter. If necessary, remove the filter, retrieve the door
and continue with the installation of the rack.

G26 UNIT._I_

SUPPLYAIR

kl _-J/LENUM
PROPERLY
SIZED FLOOR

"iX_
I _

OPENING
\ \1

1 - Align filter rack opening with the inside edge of the side
return opening. Bottom of rack should be approximately 1 inches (25mm) from the bottom and 3 inches (76mm) from the front of the unit.
2 - Screw filter rack into place with the eight self-drilling,
self-tapping screws provided. See figure 5.

FIGURE 3
NOTE - Be careful not to damage glass fiber insulation.
Check for tight seal.
Side Return Air Applications

3 - Push filter door pins through the two holes in filter door
from the inside of the u-channel. See figure 6.
4 - Position filter door on end of filter so that the thumb tab
side of the filter door is away from the fumace. Squeeze
thumb tabs to secure filter to door.

For installationswhere the return air is taken from a return
air drop, unit may be installed using either the left or right
side of furnace.

SIDE RETURN FILTER INSTALLATION
BLOWER DECK

For side return air applications, cut furnace cabinet at the
dimensions given on page 2. Embossed corners are provided on both cabinet sides for return air opening location.

RETURN

AIR

This unit is not equipped with a filter. Filter racks and reusable foam filters are available from Lennox in single
kits (44J20 for 14 x 25 filters; 44J21 for 20 x 25 filters) or
10-pack kits (66K61 for 14 x 25 filters; 66K62 for 20 x 25
filters). A filter must be in place anytime the unit is in operation.

OPENING

12 In. (305) for

14 in. (356) Filter
18 in. (457) for
20 in, (508) Filter

RETURN AIR
PLENUM SIZE
t2-3/4 in. X 23-1/2 in. (324 X 597)
for t4 in. (356) Filter
18-3/4 in. x 23-1/2 in. {476 x 597)
for 20 in. (508) Filter

1-15/16(49)
in, _

CABINET BASE BOTTOM "/4

Bottom Return Air Applications

FIGURE 5

1 - Remove blower access panel.
2 - Install filter clips, provided with unit, by slipping folded
section of clipon edge of bottom opening. See figure 4.

FILTER DOOR ASSEMBLY

3 - Place filter in bottom of blower compartment beneath
rear filterdip. Press down on filter sides. Filter clipsflex
allowing filter to snap into place.

FILTERDOOR,
PINS
B

4 - To remove filter, press clip and pull filter up and out.
FILTER DO_

BOTTOM RETURN FILTER INSTALLATION

ILTER
BACK

FILTER DOOR
PIN
_4,

SIDE FILTER CLIPS

FIGURE 6

FURNACE
FRONT

FURNACE
BASE BOTTOM

FIGURE 4

5 - Guide tilter and filterdoor into the filterrack installed on
side of furnace. Push door into filter rack until secure.
6 - To remove filter, pull filter door pins until door is re-.leased from filter rack.

Page 6

cal resistance of the cement. The cement shall show no

Useindustry-approved
standardsto sizeandinstallthe
supplyandreturnairductsystem.
Thiswillresultina quiet
andlow-static system that has uniform air distribution.
Supply Air Plenum
Furnaces installed without a cooling coil require the installation of a removable access panel in the supply air duct. The
access panel should be large enough to permit inspection (either by smoke or reflected light) of the heat exchanger for
leaks after installation. The furnace access panel must al-

gelation, stratification, or separation that cannot be removed by stirring. Refer to the table 2 below for approved
piping and fitting materials.
TABLE 2
PIPING AND FITTINGS SPECIFICATIONS
ASTM
SPECIFICATION

PIPE & FITTING MATERIAL

D1785

Schedule 40 PVC (Pipe)
Schedule 40 PVC (Cellular Core Pipe)

F891

Schedule 40 PVC (Fittings)

D2466

ways be in place when the furnace is operating and it must
not allow leaks into the supply air duct system.
Return Air Plenum

Schedule 40 CPVC (Pipe)

F441

Schedule 40 CPVC (Fittings)

F438

SDR-21 PVC (Pipe) or SDR-26 PVC (Pipe)

D2241

See dimension illustration on page 2 for proper return air
duct size.

SDR-21 CPVC (Pipe) or SDR-26 CPVC (Pipe)

F442

Schedule 40 ABS (Pipe)

D1527

NOTE - For bottom return air, return air duct should be secured to the unit using rivets or S-locks. For side return air,
secure return air duct to filter rack using screws. When using screws, take care to avoid interference with the filter
which may cause improper filtration.
The return air must not be drawn from a room where

Schedule 40 ABS (Fittings)

D2468

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

D2661

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

D2665

another gas appliance (ie., a water heater) is installed.
Even though this furnace draws its combustion air from
outside of the structure, other gas appliances that share a
utility room may not, 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 distributedthrough
the house by the furnace duct system.

NOTE - When a W-I'KX termination kit (30G79) is installed
as part of the intake and exhaust piping, add twelve feet to
the equivalent length of the pipe (the two 2 inch diameter
90 ° elbows and the 27 inch pipe in the kit).
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.
Table 3 lists the available exhaust termination kits. All Lennox vent terminations are PVC.
TABLE 3
TERMINATION KITS
Lennox Pad No.
60G77

CAUTION

All pipe, fittings, primer and solvent cement must conform with American National Standard Institute and the
American Society for Testing and Materials (ANSI/
ASTM) standards. The solvent shall be free flowing and
contain no lumps, undissolved particles or any foreign
matter that adversely affects the joint strength or chemi-

Page 7

33K97
15F75

Kit LB#
LB-49107CE
LB-87942
LB-4gl07CC

Description-Inches (mm)
2" (50,8) Concentric
_rmin_tion Kit
2" (50.8) Low Pressure Drop
Con_-_ntricTerm. Kit
2" 50.8) Roof
Tgf nination Kit

22G44

LB-49107CD

15F74

LB-49107CB

2" (50.8) Wall
Assembly Termination Kit
2" (50.8) Wall Ring Kit

44J41

LB-65678A

3" 76.2) Roof
Termination K t

44J40

LB-65701A

30G28

WTK

•2" (50.8) Wall
Termination Extended Vent

30G79

WTKX

2" (50.8) Wall
Termination Extension Riser

3" (7S.2) Wall

/L_rnhlv

Terminatinn

Kit

When making ABS joints, pieces can be prepared with a
cleaner. When joining ABS to PVC matedals, use PVC solvent cement. Refer to this procedure as specified in ASTM
D3138.

Most venting applications will require 3 inch venting for
proper unit operation. For no reason should the intake
and exhaust pipe be different diameter pipes. Regardless of the diameter of pipe used, the standard roof and wall i
terminations described in section Intake and Exhaust Piping Terminations should be used. Exhaust piping must terminate with 1-1/2 inch pipe for 1-1/2 inch or 2 inch venting
and 2 inch pipe for 3 inch venting.

Pipe used for exhaust and intake lines should be sized according to table 4. Note that maximum length of vent pipe is
for one run; either intake or exhaust. Maximum vent length
given is not the total length of intake + exhaust vents.
Each 90 ° elbow is equivalent to 5 feet (1.52m) of vent pipe.
Two 45 ° elbows are equivalent to one 90 ° elbow. One
45°elbow is equal to 2.5 feet (.76m) of vent pipe.

G26-100 OR -125 WITH 2 IN. VENTING
2 IN. VEN'_,,._P_

If intake and exhaust piping runs are not equal in length and
number of elbows, the larger diameter pipe must be used
for both runs.
TABLE 4
VENT PIPE SIZING TABLE FOR G26 FURNACES
MINIMUM DIAMETER OF INTAKE/EXHAUST PIPE
Vent Pipe
Equivalent Length
Max, Feet (Meters)

G26-50
50,000
BTU

G26-75
75,000
BTU

G26-100
100,000
BTU

G26-125
125,000
BTU

15 (4.57m)

1-1/2"

20 (6.10m)

25 (7.62m)

30 (9.14m)

40 (12.19m)

50 (15.24m)

55 (16,76m)

60 (10.29m)

70 (21.34m)

80 (24.38m)

3°

90 (27.43m)

100 (30.48m)

110 (33.53m)

120 (36.58m)

130 (39.62m)

¢,..1

3 IN. X 2 IN.

I-1" /REDU'%E'D
I

2IN
OUT

PROVIDED

I 3IN'
IN

G26-100 OR -125 WITH 3 IN. VENTING
31N. X21N.
REDUCER

2,N

PROVIDED

IV
I I

NIPPLE
2IN.
OUT

IN. VENT PIPE

I 3IN.
IN

FIGURE 7

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

NOTE - M inchpipe forG26-50is 5 feet and2 elbowsof 1.5 inch diameter
pipe.
NOTE - M inchpipe for G26-75 is 5 feetand 2 elbowsof 2 inchdiameter
pipe.
NOTE - M inchpipe forG26-100 is 5 feetand2 elbows of 2 inchdiameter
pipe.
NOTE - M inchpipe for G26-125 is 5 feetand2 elbowsof 2 inchdiameter
pipe.
NOTE - When a WTtO( termination kit is installed as part of
the intake and exhaust piping, the two 2 inch diameter 90 °
elbows and the 27 inch pipe (in the kit) should be included
in the maximum vent pipe length for each run.

1 - Measure and cut vent pipe to desired length.
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.
3 - Clean and dry surfaces to be joined.

For -50 and -75 kBtuh units, connections are provided for 2

4 - Test fitjoint and mark depth of fitting on outside of pipe.

inch diameter venting which should satisfy most venting re-

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

quirements. No transition pieces are provided
for 2 inch venting.

or needed

For -100 and -125 kBtuh units, the intake connection

sized for 3 inch diameter pipe. The exhaust connection has
a 2 inch nipple. A pipe transition piece is shipped with the
unit to connect to 3 inch pipe. See figure 7 for 2 inch and 3
inch venting applications.

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.

Page 8

1 - Cement intake piping in slip connector located at top
of unit.

NOTE - -iTmeis cdtical at this stage. Do not allow pnmer to dry before applying cement.

2 - Route piping to outside of structure. Continue with
installation following instructions given in exhaust and
intake piping termination section.

7 - Immediately after applying last coat ofcement 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. Tum pipe 1/4 turn dudng assembly (but not after pipe is fully inserted) to distribute
cement evenly.

Exhaust

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/air intake
pipes may be installed is a minimum of 3 inches (610 mm),
and a maximum of 24 inches (610mm). If a G26 furnace replaces a fumace which was commonly vented with another
gas appliance, the size of the existing vent pipe for that gas

Piping

1 - Cement exhaust piping into flue collar socket located
on the left side of the top cap.
2 - All horizontal runs of exhaust pipe must slope back toward unit.
12 inches
drainage.
supported

A minimum of a 1/4 inch (6mm) drop for each
(305mm) of horizontal run is mandatory for
Horizontal runs of exhaust piping must be
every 5 feet (1.52m) using hangers.

NOTE - Exhaust piping should be checked carefully to
make sure there are no sags or low spots.
NOTE - Exhaust piping must be insulated with 1/2 inch
(13mm) Armaflex or equivalent when run through unheated space. Do not leave any area of exhaust pipe
open to outside air; exterior exhaust must be insulated
with 1/2 inch (13mm) Armaflex or equivalent.

appliance must be checked. Without the heat of the odginal
furnace flue products, the existing vent pipe is probably
oversized for the single water heater or other appliance.
The vent should be checked for proper draw with the remaining appliance.

CAUTION

A WARNING

Removal of Unit from Common Venting System
In the event that an existing furnace is removed from a
venting system commonly run with separate gas appliances, the venting system is likelyto be too large to propedy vent the remaining attached appliances. The following
test should be conducted while all appliances (both in operation and those not in operation) are connected to the
common venting system. If the venting system has been
installed improperly, corrections must be made as outlined
in the previous section.
1 - Seal any unused openings in the common venting system.
2 - Visually inspect the venting system from proper size
and horizontal pitch and determine there is no blockage or restdction, leakage, corrosion and other deftciencies which could cause an unsafe condition.

Intake Piping

Page 9

Close all building doors and windows and all doors between the space in which the appliances remaining

Intake and exhaust pipes should be placed as close

together as possible at termination end (refer to illustrations). Maximum separation is 3 inches (76mm) ,on roof terminations and 6 inches (152mm) on side
wall terminations.

connected to the common venting system are located
and other spaces of the building.Turn on clothes dryers and any appliances not connected to the common
venting system. Turn on any exhaust fans, such as
range hoods and bathroom exhausts, so they will operate at maximum speed. Do not operate a summer
exhaust fan. Close fireplace dampers.

Exhaust piping must terminate straight out or up as
shown. In rooftop applications, a 2 inch X 1-1/2 inch reducer for 2 inch venting, 3 inch x 2 inch reducer for 3

inch venting must be used on the exhaust piping at the
point where it exits the structure to improve the velocity
of exhaust away from the intake piping.

4 - Follow the lightinginstruction. Place the appliance being inspected in operation. Adjust thermostat so appliance will operate continuously.

On roof terminations, the intake piping should terminate straight down using two 90 ° elbows (See figure 8).

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

A IMPORTANT

6- After you have determined that each appliance remaining connected to the common venting system
properly vents when tested as outlined above, return
doom, windows, exhaust fans, fireplace dampers and
any other gas-burning appliance to their previous condition of use.
7- If improper venting is observed during any of the
above tests, the common venting system must be corrected. The common venting system should be resized to approach the minimum size as determined by
using the appropriate tables in appendix G in the current standards of the National Fuel Gas Code ANSI
Z223-1 in the U.S.A., and the appropdate Category 1
Natural Gas and Propane appliances venting sizing
tables in the current standards of the CAN/

NOTE - If winter design temperature is below 32°F (O°C),
exhaust piping must be insulated with 1/2 inch (13mm),
Armaflex or equivalent when run through unheated
apace. Do not leave any surface area of exhaust pipe
open to out-side air; exterior exhaust pipe must be insulated with I/2 inch (13mm) Armaflex or equivalent. In extreme cold climate areas, 3/4 inch (19mm) Armaflex or
equivalent is recommended. Insulation on outside runs oi
exhaust pipe must be painted or wrapped to protect insulation from deterioration.
Inches(mm)

3(76 MAX.__
_

CGA-B149.1 and .2 in the Natural Gas and Propane
Installation Code in Canada.

Intake and Exhaust Piping Terminations

8 (203I MIN

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 8 through 20 show typical terminations.

1/2 (13) FOAM
INSULATION IN
UNCONDITIONED
SPACE

12 (305) ABOVE

ACCUMULATION
AVE"*OESNOW

3 (76) OR
2 (51) PVC

1 - Use recommended piping materials for both intake
and exhaust piping.

UNCONDITIONED
ATTIC SPACE

PROVIDE SUPPORT
FOR INTAKE AND
EXHAUST LINES

2 - Secure all joints, including drain leg, gas tight using
approved cement.
3 - Piping diameters should be determined according to
length of pipe run. See table 4. Locate intake piping
upwind (prevailingwind) from exhaust piping. To avoid
re-circulation of exhaust gas on roof terminations, end
of exhaust pipe must be higher than intake pipe.
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.

3 x 2 (76 x 51) OR
2 x 1-1/2 (51 x 38)
PVC REDUCER

ROOF TERMINATION KIT
(15F75) LB-49107CC for 2 (51) Venting
(44J41) LB-65678A for 3 (76) Venting

FIGURE 8
NOTE -Dudng
extremely cold temperatures, belov_
approximately 20°F (6.67°C), units with long runs of venl
pipe through unconditioned space, even when insulated,
may form ice in the exhaust termination that prevents the

Page 10

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.
NOTE - Care must be taken to avoid recirculation
haust back into intake pipe.

1/2 (13) ARMAFLEX
INSULATION IN
UNCONDITIONED
SPACE

Inches(mm)

of ex-

6 - On field supplied terminations for side wall exits, exhaust piping should extend a maximum of 12 inches
(3O5mm) beyond the outside wall. Intake
should be as short as possible. See figure 9.

112 (12.7) FOAM INSULATION
IN UNCONDITIONED SPACE

piping

Optional Turndown
Shown
(Intake Only)

TOP VIEW
WALL TERMINATION
(22G44) LB49107CD for 2 (50.8) Venting
(44J40) LB-65701A for 3 (76.2) Venting

FIGURE 10
EXHAUST
TERMINATION

12 (305) MIN.

12 (305) ABOVE
AVERAGE SNOW
ACCUMULATION

2 X 1-1/2

(51 x 38)

1-1/2

2 (011

_VC

1/2 (13) ARMAFLEX
INSULATION

TERMINATION

0(J02)

MAXIMUM

_INTAKE

21_
PVC
COUPLING

OUTSlOE
J
WALL
Inches (ram)

MINIMUM [
TOP

F.XHAUST

VIEW

WALL RING KiT
(15J74) LB-49107CB for 2 (50.8) Venting

CONCENTRIC ROOFTOP TERMINATION
(60G77) LB49107CE for G26-50 & -75 Units Only
(33K07) LB-87942 for G26-t00 & -125 Units Only

FIGURE 9

FIGURE 11

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-

INTAKE

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 feet
(.91m) as shown in figure 15. Refer to figures 13 and
14 for proper piping method. WTK wall termination kit
must be extended for use in this application. See figure 18 or use kit WTKX shown in figure 19. When exhaust and intake piping must be run up an outside
wall, the exhaust piping is reduced to 1-1/2 inches
(38ram) 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 11

EXHAUST
EXHAUST

INATION

TERMINATION

12 (305)Mln,
Inches (mm)

CONCENTRIC

WALL TERMINATION

(60G77) LB-49107CE for G26-50 & -75 Units Only
(33K97) LB-87942 for G26-100 & -t25 Units Only

FIGURE 12

12 (305) MIN. for 2 (51)

A IMPORTANT

Inches(ram)
20 (508) MAX. for 3 (75)I
UNCONDITIONED
SPACE

OUTSIDE

WALL

FOR INTAKE
AND
PROVIDE
SUPPORT
EXHAUST LINES EVERY
36 (914)

12
A
BOVE
AVERAGE SNOW
ACCUMULATION

A IMPORTANT

1/2 (13) FOAM
INSULATION

UNCONDITIONED
SPACE

1/2 (13) FOAM
INSULATION

SIDE VIEW
WALL RING TERMINATION

(15F74)LB-49107CBfor 2 in.(51)Venting

Inches(mm)

"This reducer is not necessary for G26-50 units using 1-1/2 In. venting,
See venting table 4 for maximum venting lengths with this arrangement.

1/2 (13)
FOAM
iNSULATION

3 (75)OR

FIGURE 13

3 x2(76x51) OR
2 x 1-1/2 (51 x 38)
REDUCER BUSHING LOCATION
FOR OFFSET TERMINATION

2 (51) 90 ° ELBOW

g - Position termination ends so they are flee from any obstructions and above the level of snow accumulation
(where applicable). Termination ends must be a minimum of 12 inches (305mm) above grade level. Do not
point into window wells, stairwells, alcoves, courtyard
areas or other recessed areas. Do not positiontermination ends directlybelow roofeaves or above a walkway.
Since the G26 is a certified direct vent, Category IV gas
furnace, the location of the termination is limited by local building codes. In the absence of local codes, refer
to the current National Fuel Gas Code ANSI Z223-1 in
U.S.A., and current standards CAN/CGA-B149.1/.2 of
the Natural Gas and Propane Installation Instructions in
Canada for details. The termination should be at least

3 (75)OR
(NOt Shown)
May Be Used on

Intake Only

2 (51) 90 ° ELBOW
Inches (mm)

FRONT VIEW
WALL TERMINATION
(22G44) LD-49107CD for 2(51) Venting
(44,140) LB-65701A for 3(76) Venting

FIGURE 14
METAL OR PLASTIC
STRAPPING _,_
OR LARGE WIRE TIES

12 inches (305mm) from any opening through which
flue products could enter the building.
When horizontally vented, minimum clearance for termination from electric meters, gas meters, regulators
and relief equipment is 4 feet (1.2m) for US installations. Refer to the current CAN/CGA-B149.1 and .2 for
installations in Canada or with authorities having local
jurisdiction.
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.

FIGURE 15
10 - Suspend piping using hangers at a minimum of every5 feet (1.52m) for schedule 40 PVC and every 3 feet
(.91m) for ABS-DWV, PVC-DWV, SPR-21 PVC, and
SDR-26 PVC piping. A suitable hanger can be fabricated by using metal or plastic strapping or a large
wire tie.
11 - 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.
12 - Isolate pipingat the pointwhere it exits the outside wall
or roof.

Page 12

13 - When furnace is installed in a residence where unit is
shut down for an extended peded of time, such as a
vacation home, make provisions for draining condensate collection trap and lines.
14 - 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 17.

COVEREXHAUST
VENT WITH
112 (13)
FOAM
INSULATION

12
(3os)

Front View

INTAKE
AIR

EXHAUST
AIR
12 MIN
(305)
AbOveGrade

(127) _

/ /
Front View

Iq_

1_5, -_/

EXHAUSTVENT
INTAKE
AIR

Side View
----_n

////

U_im_

(ram)

Inches

VENT
1/2 (13) Foam

Side View

EXHAUST VEN_

Mnmum

305

GRADE
ABOV_GRADE

_JIIIIIIIIIIIIIII

VENT TERMINATIONS
MOOEL WTK WALL TERMINATION KIT (30G28)
EXTENDED VENT FOR GRADE CLEARANCE

INTAKE VENT

Inches (mini

FIGURE 18

OUTSIDE WALL

VENTTERMINATIONS
WALLTERMINATION
KIT (30G28) WTK

I'Front View

FIGURE 16

-'I

0,,_

INTAKE

Front View

VENT

_. EXHAUSTvENT
NOTE-Enclosed
exhaust pipe
is insulated with 1/2 in, (13ram)
foam Insulatfon. ff intake and

exhaust
pipe8
arerev,,._,s_
and

remove

foam

EXHAUST

12 _

GRADE

. ..l_'::_J_.._.. ,,,

p---

Side View

EXHAUST VENT
Side View

Inches (ram)

insulation

and reapply to other vent. Exhaust vent must be insulated.

':" :/"

STVENT

_NTAKE

°°

_
VENT
OPTIONAL VENT TERMINATION FOR
MULTIPLE UNIT INSTALLATION
WALL TERMINATION KIT WTK

VENT TERMINATIONS
MODEL w'rKx (30G79)
EXTENSION RISER FOR GRADE CLEARANCE

FIGURE 17

FIGURE 19

Page 13

3 - Use the provided adapter (1/2 inch PVC x 1/2 inch
MPT) and the nipple (1/2 inch PVC) to carry drainage
outside the cabinet. If a field substitute is needed, 1/2
inch CPVC x 1/2 inch MPT adapter and 1/2 inch CPVC
is acceptable for use.

G26 VENTING IN EXISTING CHIMNEY
c_x1_

n_r

4 - Glue nipple to the adapter using the procedures outlined in the "Joint Cementing Procedures" section.
The nipple/adapter assembly should be connected in
a non-permanent manner and must be water tight.
Teflon tape is recommended to seal the joint.
For Right-Hand Side Condensate Exit:
Install the nipple/adapter assembly from the outside
of the cabinet and insert the adapter into the threaded
opening in the condensate trap.
For Left-Hand Side Condensate Exit:
Insert nipple/adapter assembly from the left hand
side of the cabinet and through the combustion air
inducer mounting structure into the threaded opening in the condensate trap.

or vent stack. If vertical discharge through an existing unused chimney or stack is required, insert piping
inside chimney un_l the pipe open end is above top of chimney and terminate as illuStrated. In any exteriorper6on of chimney, Itm exhaust vent must be insulated. An aHerhate method is to fill the chimney w_h
acoustic and thermal properties.

¥emliculita

or equal

to take

advantage

of its

FIGURE 20
Condensate Piping
This unit is designed for either dght- or left-side exit of condensate piping. Condensate drain line should be routed
only within the conditioned space to avoid freezing of condensate and blockage of drain line, An electric heat cable
should be used where condition is exposed to unconditioned areas.

5 - Connect field supplied plumbingto nipple and route to
open drain. Plumbing shouldbe vented to a point higher
than the condensing coil. See figure 22.
CONDENSATE
(Plumbing

PLUMBING

must be vented higher than coil.)

CAUTION

1 - Determine which side condensate will exit the unit.
2 - Connect a 1/2 inch (13mm) plastic pipe plug (provided)
in the unused end ofthe condensate trap, Installplug so
that it is sealed water tight yet able to be removed. Do
not permanently seal the connection. Teflon tape is recommended to seal joint. See figure 21.
CONDENSATE ASSEMBLY
(Forleftor rlghtInstallation)
COLD HEADER
BOX

COMBUSTION AIR
INDUCER BRACKET

FIGURE 22
NIPPLE

ADAPTER

CONDENSATE TRAP
NIPPLE

PLUG

BOOT OR CAP

ADAPTER

FIGURE

Page 14

Connect condensate drain line (1/2 inch [13mm] SDR
11 plastic pipe or tubing) to condensate connection on
drip leg assembly and route to open drain. Condensate line must be sloped downward away from drip leg
to drain. If drain level is above drip leg, condensate
pump must be used to condensate line. Condensate
drain line should be routed within the conditioned
space to avoid freezing of condensate and blodkage of
drain line. If this is not possible, a heat cable kit may be

used on the condensate drip leg and line. Heating
cable kit is available from Lennox in various lengths;
6feet (1.8m) - kit no. 18K48; 24 feet (7.3m) - kit no.
18K49; and 50 feet (15.2m) - kit no. 18K50.

.....

When left-hand gas plumbing is required, gas line
should be installedin the lower half of knockout so that
piping will clear combustion air inducer. See figure 23.
4-

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 bottom of the valve as shown in
figure 23.

LEFT SIDE PIPING

The piping should be sloped 1/4 inch (6.4 ram) per 15
feet (4.57 m) upward toward the meter from the furnace. The piping must be supported at proper intervals [every 8 to 10 feet (2.44 to 3.01 m)] using suitable
hangers or straps. A drip leg should be installed in vertical pipe runs to the unit.
In some localities, codes may require installation of a
manual main shut-offvalve and union(furnished by installer) external to the unit. Union must be of the
ground joint type.

MANUAL
MAIN SHUTOFF
VALVE

AIMPORTANT

1/8 IN. NPT
PLUGGED
TAP _

I_,

_
GAS VALVE

....
_
___ _=_L_

RIGHT SIDE PIPING
(STANDARD)

HO"A'
ES'P"E"O"E
II
118IN.13.2mmlN.P.T.1_.
II ISOLATE

/|
_'
/

_="
B

1/8 IN. NPT
PLUGGED

FIGURE 24

/TAP

NO TE - Install a 1/8 inch NPT plugged tap in the field piping upstream of the gas supply connection to the unit.
The tap must be accessible for test gauge connection.

GAS VALVE

FIGURE 23
2- When connecting the gas supply, factors such as
length of run, number of fittings and furnace rating
must be considered to avoid excessive pressure drop
Table 5 lists recommended pipe sizes for typical ap-

See figure 24.
Leak Check
After gas piping has been completed, carefully check all
piping connections (factory and field) for gas leaks. Use a
leak detecting solution or other preferred means.

plications.
NOTE-

Use two wrenches when connecting gas pip-

ing to avoid transferring torque to the manifold.
3 - The gas piping must not run in or through air ducts,
clothes chutes, gas vents or chimneys, dumb waiters
or elevator shafts. Center gas line through piping hole.
Gas line should not touch side of unit.

Page 15

ACAUTION

TABLE 5
GAS PIPE CAPACITY - FT31HR (kL/HR)
Nominal
Iron Pipe Size
-Inches(mm)

Internal
Diameter
-Inches(mm)

Length
10

(3,048)

(6.096)

(9.144)

of Pipe-Feet(m)

(12.192)

(15.240)

60
(18.288)

70
(21.336)

80
(24.384)

90
(27.432)

100
(30,480)

1/4
(6.35)

364
(9.246)

43
(1J3)

29
(.82)

24
(.68)

20
(.57)

18
(.51)

16
(,45)

15
(.42)

14
(.40)

13
(.37)

12
(34)

3/8
(9.53)

.493
(12.522)

95
(2.69)

65
(1.84)

52
(1.47)

45
(1.27)

40
(1.13)

36
(1.02)

33
(.73)

31
(.88)

29
(.82)

27
(.76)

1/2
(12.7)

,622
(17.799)

175
(4,96)

120
(3.40)

97
(2.75)

82
(2,32)

73
(2.07)

66
(1.87)

61
(1.73)

57
(1.61)

53
(1.50)

50
(1.42)

3/4
(19.05)

824
(20.930)

360
(10,19)

250
(7.08)

200
(5.66)

170
(4.61)

151
(4.28)

138
(3.91)

125
(3.54)

118
(3.34)

110
(3.11)

103
(2.92)

1
(25.4)

1.049
(26.645)

68O
(19.25)

465
(13.17)

375
(10.62)

326
(9.06)

285
(8.07)

260
(7.36)

240
(6.80)

220
(6.23)

205
(5.80)

195
(5.52)

1-1/4
(31.75)

1.380
(35.052)

1490
(39.64)

950
(25.90)

770
(21.60)

660
(16,69)

580
(16.42)

530
(15.01)

490
(13,67)

460
(13.03)

430
(12.18}

400
(11.33)

1-1/2
(36.1)

1.610
(40.894)

2106
(89.46)

460
(41.34)

1180
(33.41)

990
(26.03)

900
(25.46)

810
(22,94)

750
(21.24)

690
(19.54)

650
(16.41)

620
(17.56)

2
(50.8)

2.967
(52.802)

3950
(111.85)

2750
(77.87)

2200
(62.30)

1900
(53.80)

1680
(47.57)

1520
(43.04)

1400
(39.64)

1300
(36.81)

1220
(34.55)

1150
(32,56)

2-1/2
(63.5)

2.469
(67.713)

6300
(178.39)

4350
(123.17)

3520
(99.67)

3000
(84.95)

2650
(75.04)

2400
(67.96)

2250
(63.71)

2050
(58.05)

1950
(58.22)

1850
(52.38)

3
(76.2)

3.068
(77.927)

11000
(311.48)

7700
(218.03)

6250
(176.98)

5300
(150.07)

4750
(134.50)

4300
(121.76)

3900
(110.43)

3700
(104,77)

3450
(97.69)

3250
(92.03)

4
(101.6)

4.026
(102.260)

23000
(651.27)

15800
(44739)

12800
(362.44)

10900
(308.64)

9700
(274.67)

8800
(249,18)

8100
(229.36)

7560
(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 0.60 specific gravity gas.

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.).

tion purposes. Refer to figure 29 for control box arrangement, figure 30 for a detail of the Surelight
integrated
control, figure 31 for schematic wiring diagram and troubleshooting, and figure 32 for point to point field wiring. :
ELECTROSTATIC DISCHARGE (ESD)
TM

Precautions and Procedures

ACAUTION

A field make-up box is provided for line voltage wiring. Line
voltage wiring to unit is done through the J69 jack from the
field make-up box to plug P69 from the control box. See figures 25 and 26 for make-up box installation.
Figure 28 shows thermostat

designations

1 - Install field make-up box on either side, inside or out of

for identifica-

Page 16

the cabinet. Knockouts are provided in box and cabinet to run wiring. See figures 25 and 26.

the star washer breaks the paint on the cabinet so
that the washer is touching metal. Unit is not properly grounded if paint has not been removed by star
washer.

INTERIOR
MAKE-UPBOXINSTALLATION

BUSHING

An optional 120 volt accessory wire is provided with
G26 units. Install brown accessory wire into J69 jack
plug by inserting the pin of the brown wire into the open
socket of the jack. See figure 27. Any accessory rated
up to 4 amps can be connected to this wire. Connect

P69 from
Control Box

INSTALLING
BROWN
ACCESSORY
WIRETOJ69
BROWN

the neutral leg of the accessory to the neutral white wire
in the make-up box. The accessory terminal is energized whenever the blower

FIGURE 25
EXTERIOR MAKE-UP BOX INSTALLATION

NEUTRAL

is in operation.
Insert the three-pin (P69)
plug from the control box

MAKE-UP
BOX
BUSHING

FIGURE 27

into the knockout provided in the blower deck.
_

Connect jack (J69) from make-up box to jack plug in
blower deck.

7- Select wire size accordingto the blower motoramps.
8- Snaphole bushing is provided for the widng entry hole
in the cabinet. A snaphole plug is provided to seal the
unused wire entry hole.

J69
(Shown wlth
accessory
wire connected)

P69 from
Control Box
FIGURE
2-

Remove

cap from knockout

in blower

same side as the installed make-up

deck on the

Install room thermostat according to instructionsprovided with thermostat. See figure 28 for thermostat designations. Iffurnace is being used with heat pump refer
to FM21 installation instruction.

10- Install a separate fused disconnect switch near the
unit so power can be turned off for servicing.

box.

G26 and CONDENSING UNIT
THERMOSTAT DESIGNATIONS

AIMPORTANT

(Refer to specific thermostat and outdoor unit.)
Thermostat

G26
Furnace

Condensing

3 - Electrically ground unit in accordance with local codes
or, in the absence of local codes, in accordance with the
current National Electdc Code (ANSI/NFPA No. 70)
and in Canada with the current Canadian Electdc Code
part 1 (CSA standard C22.1). The ground wire is provided in the field make-up box.
To ensure proper grounding of the furnace, two star
washers are included in the electrical make-up box
bag assembly. Place the star washer on securing
screw before installing the make-up box. Make sure

Page 17

®
® ,NDOO,.LOWE,
®1
@
@j
®
owE, ®j

COMMON

Unit
HS UNIT

coMP.Esso.

.SUNiT
/

_COMMON

FIGURE 28
11 - Complete widng connecfions to equipment using wiring
diagrams provided_
unitand in figures31 and 32. Use
18-gauge wire or larger for thermostat connections.

IndoorBlowerSpeeds(Referto Figure31)
1- When the thermostat is set to "FAN ON",

G26CONTROLBOX

the indoor
blower will run continuously on low speed when there
is no cooting or heating demand.

TRANSFORMER

2 - When there is a cooling demand, the indoor blower will
run on the cooling speed.
3 - When there is a heating demand, the indoor blower
will run on the heating speed.

CIRCUIT
BREAKER

•

DOOR
INTERLOCK
SWITCH

SURELIGH _
CONTROL

DETACHABLE
TERMINAL STRIP

FIGURE 29

SURELIGHT
P_

PAF_ ACB

ACC

12OVAC HTG

INTEGRATED CONTROL BOARD
12o VAC RETtJ_
NEUTRALS

IIH

LOW

TX.o,
,co
÷
111t

Ilnll
m

MEUTRALS

C>j2 _

TERMINAL DESIGNATIONS
ACS COOL
Blower - Cooling Speed (Line Volt)
ACS HEAT
Slower - Heating Speed (Line Volt)
PARK
Alternate Blower Speeds (Dead)
ACB LOW
Continuous Low Speed Blower
ACC
Accessory Terminal (Line Volt)
TX
120VAC Hot to Transformer
HOT
120VAC Hot Input
HTG ACC
Heat Only Accessory (Line Volt)
NEUTRALS
120VAC Neutrals
24VAC HOT
24VAC Hot fTom Transformer
24VAC RTN
24VAC Return fTom Transformer
FLAME SENSE
Flame Sense Terminal

I6_ITION SYST(_

ANSI
_Z00_5
ATG_IATIC
Z4VAC_ZI
60Hz
A MAX_

÷
FLAME

S!-I
0_F
OFF
(_N

SI-2
TIME
OFF 60 9EC
ON
90 5EC
OFF +20 SIEC

HEATOFFBELAY

SENSE

I
r

I
I
I

I
i

__
F

___

--_

I
I

®
Y

FIGURE 30

Page 18

TYPICAL
I20v ACC
On
K43 EC_I
(IF US_}

SiS
_UB_STION AIR

G26 WIRING

DIAGRAM
_TAT
HEAT
.'_HT
ICIPAT I_4_l
_TTIN65

510
PRIMARY 6AS
LIMIT

$47
FL_ME R_J=0UT
SVITGH

CIOR_
_USTU_ON
MOTOR
N_
LI m

BLOtER _PEEO CHART
IFACTOAy CONNECTED5PE]EDTAPS

_.-50

I.....
....

B{.ACE

_]_-IO0,
JI56_
(J2)

I_1

IYI[U.IN I

....
....
InA_lnl

HI • BLOCRRSPEE_ _TI_,
IELAf_X
YI_J_q

CIRCUIT
BI_J_I_

I_LACE BROTH
SI
ROOMTHERf_TAT

lAdlING_LEC_IIC _
0t fl_IIt,UN

FIGURE 31
Page19

T _

PaIF

HAZARDCAN _U_
8_ _

I....
YELLOW
Ig_qO_q
I'_I.LOI
IBI_IE
LO
R_)

YELLO_ R£D

INJURy
IN A_clO_E

TYPICAL

G26 FIELD WIRING

DIAGRAM

GND

==odi
ROLLOUT
SWITCH
FLAME

°°l

LIMIT

--Z
znl
00(3

FIELD
MAKE-UP

AIR PROVE
COMBUSTION
SWITCH

BOX
RI

v%,%
I

ACK

WHITE

BROWN

,II'
I

TRANSFORMER

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ii
ii
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CONTROL

ooddl

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I LIGAON L

TO ACCESSORY IF USED.
(ELECTRONIC
AIR CLEANER)
IF NOT NEEDED, DO NOT INSTALL
ACCESSORY
WIRE IN J69.

DOOR
INTERLOCK
SWITCH

---

TO COMPRESSOR
CONTACTOR

FIELD INSTALLED
FIELD iNSTALLED

CLASS II 24V VOLTAGE
UNE VOLTAGE

FIGURE 32
Gas valve may be equipped with either a gas control knob
or lever. Use only your hand to push in or turn the gas control knob or move the gas control lever. Never use tools. If

FOR YOUR SAFETY READ BEFORE LIGHTING

the knob will not push in or turn or if lever will not move by
hand, do not try to repair it, call a qualified service technician. Force or attempted repair may result in a fire or explosion.

AWARNING

G26 units are equipped with a SureLighU" ignition system. Do not attempt to manually light burners on this furnace. Each time the thermostat cells for heat, the burners
will automatically light. The ignitor does not get hot when
there is no cell for heat on units with SureLight
system.

ignition

Gas Valve Operation (Figure 33)

AWARNING

ACAUTION

1 - STOP! Read the safety informationat the beginning of
this section.
2 - Set thermostat to lowest setting.
3 - Turn off all electrical power to furnace.
4-

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

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

5 - Remove the unit access panel.

Page 20

3 - Remove heat section access panel.

HONEYWELL
VR8205
SERIES
GASVALVE

4 - On Honeywell VR8205 gas valves, turn knob on gas
valve clockwise4_ to OFF. For White Rodgers 36E
gas valves, move switch to OFF Do not force.
5 - Replace the unit access panel.

JGas Pressure

Adjustment

Gas Line Pressure
\

Check gas fine pressure with unit firing at maximum rate. A
minimum of 4.5 inches w.c. (1.12kPa) for natural gas or 8.5
inches w.c. (2.11kPa) for LP/propane gas should be maintained.

GAS VALVE SHOWN IN OFF POSITION

WHITE RODGERS
36E GAS VALVE

Gas Manifold Pressure
GAS VALVE
SHOWN
iN OFF
POSITION

After line pressure has been checked and adjusted, check
regulator pressure. See table 6 for correct manifold pressures for LP/propane and natural gas at altitudes in a range
of 0 to 7500 feet (0 to 2248m).

TABLE 6
FIGURE 33

6 - Whffe Rodgers 36E Gas Valve - Switch gas valve leverto OFF. See figure 33.
Honeywell VR8205 Gas Valve - Turn knob on gas
valve clockwise_lt' to OFF. Do not force. See figure
33.

Unit (Fuel)

Manifold Pressure (outlet)
from 0 to 7500 ft. (0 to 2248nl) above sea level

Natural

3.5" w.c. (.87 kPa)

L.P.IPropane

7.5" w.c. (1.86 kPa)

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.

&WARNING

8 - White Rodgers 36E Gas Valve - Switch gas valve lever
to ON.
Honeywell VR8205 Gas Valve -Tum knob on gas valve
counterctockwi_
to ON. Do not force.

HONEYWELL GAS VALVE
GAS VALVE
CONTROL KNOB

9 - Replace unit access panel.

WIRING
TERMINALS

10- Turn on all electrical power to unit.
INLET
PRESSURE
TAP

11- Set thermostat to desired setting.
NOTE - When unit is initiallystarted, _eps 1 through 11
may need to be repeated to purge air from line.

NOTE- On initial start-up and when condensate trap is
dry, unit may turn itseff off and on to allow condensate
trap to fill. This is normal operation.
12- If the furnace wii/not operate, follow the instructions
=To Turn Off Gas To Unit" and call your service technician or gas supplier.

_BARBED
OUTLET
PRESSURE
TAP

FITnNG FOR
PRESSURE
SWITCH
HOSE

To Turn Off Gas To Unit
1 - Set thermostat to lowest setting.

PRESSURE
REGULATOR
(UNDER CAP SCREW)

2 - Turn offall electrical power to unit if service is to be performed.

Page 21

FIGURE 34

NOTE - Shut unit off and remove manometer as soon as an
accurate reading has been obtained. Take care to replace
pressure tap plug.
NOTE - During this test procedure, the unit unit will be overfiring:

WHITE RODGERS 36E GAS VALVE
REGULATOR ADJUSTMENT SCREW LOCATION
_'_

REGULATOR
COVER SCREW

• Operate unit only long enough to obtain accurate reading to
prevent oveilleaUng heat exchanger.
• Attempts to clock gas valve during this procedure will be
inaccurate. Measure gas flow rate only during nor-mal
unit operation.

ADJUSTING
SCREW

6 - When test is complete remove obstruction from hose
and return hose to gas valve barbed fitting.
Gas Flow

FIGURE 35

Manifold Pressure Measurement & Adjustment
NOTE - Pressure test adaptor kit (10L34) is available from
Lennox to facilitate manifold pressure measurement.
1 - Connect test gauge to outlet tap on gas valve.
2 - Disconnect pressure sensing hose from gas valve and
plug hose by covering opening with tape or equivalent.
Leave barbed fitting on valve open to atmosphere.
See figure 36.
DIFFERENTIAL

PRESSURE

SWITCH

CIRCUITRY
BURNER
BOX
BARB

Heat Anticipation Settings
Thermostat anticipator setting (if adjustable) should be set
according to amps listed on wiring diagram on unit.
Flame Rollout Switch
Factory set: No adjustment necessary.
Limit Control
Factory set: No adjustment necessary.
Pressure Switch

BOX
SENSING
HOSE
GAS
VALVE
SENSING
HOSE
GAS
VALVE

AIRINDUCER

Unit does not need gas pressure adjustmentwhen operating
from 0 to 7500 feet (0 to 2248m). See table 6 for correctmanifold pressures for LP/propane and natural gases.

Natural to LP/Propane Changeover
A natural gas to LP/propane gas changeover kit is required
to convert unit. Refer to installation instructions supplied
with kit for conversion procedure.

PRESSURE

COMBUSTION
AIR PRESSURE _
SENSING HOSE

To checkfor propergas flow tothe combustion chamber, determine the Btu (kW) input from the unit rating plate. Divide
this input rating by the Btu (kW) per cubic foot (cubic meter)
of available gas. The result is the required number of cubic
feet (cubic meter) per hour. Determine the flow of gas
through the gas meter for two minutes and multiplyby 30 to
get the houdy flow of gas.

Factory set: No adjustment is necessary.
Fan Control
The fan-on delay of 45 seconds is not adjustable. The fanoff delay (time that the blower operates after the heating
demand has been satisfied) can be adjusted by moving the
jumper on the SureLight integrated control. The unit is

•PRESSURE
SWITCH
SENSING
HOSE

LEFT SIDE OF PRESSURE SWITCH = MORE NEGATIVE
RIGHT SIDE OF PRESSURE SWITCH = LESS NEGATIVE (Closer to Zero)

FIGURE 36
3 - Start unit and allow 5 minutes for unit to reach steady
state.

shipped with a factory fan-off delay of 90 seconds. The fanoff delay will affect comfort and is adjustable to satisfy individual applications. See figure 37.

4 - Examine the burner flame. The flame should be stable

FAN-OFF TIME ADJUSTMENT
60sec,

90sec.

120sec.

180sec.

and should not lift from the burner. Natural gas should
bum blue. L.P./propane gas should bum mostly blue
with some orange streaks.
5 - After allowing unit to stabilize for 5 minutes, record
manifold pressure and compare to values given in
table 6.
Page 22

To adjust fan-off timing, flip dip switch to desired setting.

FIGURE 37

TemperatureRise

3 - Check for correct voltage at unit (unit operating).

Check temperature rise and, if necessary, adjust blower
speed to maintain temperature rise within range shown on
unit rating plate.
Electrical

4 - Check amp-draw on blower motor.
Motor Nameplate
Actual
5 - Check to see that heat (if applicable) is operating.
Blower

1 - Check all wiring for loose connections.
2 - Check circuit breaker located on unit control box.

C'heck the blower wheels for debris and clean if necessary.
The blower motors are prelubricated for ex-tended bearing
life. No further lubrication is needed.

3 - Check for correct voltage at the furnace (furnace operating).

Filters

4 - Check amp-draw on blower motor.
Motor Nameplate
Actual

1 - Filters must be cleaned or replaced when dirty to assure proper furnace operation.

NOTE - Do not secure electrical conduit directly to ducting
or structure.

2 - Reusable foam filters used with G26 can be washed

Blower Speeds
Refer to blower speed selection chart on unit wiring diagram.

with water and mild detergent. When dry, they should
be sprayed with filter handicoater prior to reinstallation. Filter handicoater is RP Products coating no. 418
and is available as Lennox part no. P-8-5069.

NOTE - CFM readings are taken external to unit with a dry
evaporator coil, filter installed and without any other accessories.

3 - If replacement is necessary, order Lennox part no.
31J81 for 14 inch x 25 inch (356 x 635mm) filter for
G26-50 and -75 units and P-8-7831 for 20 inch x 25

Electronic Ignition
The SureLight"
integrated control has an added internal
watchguard feature. The feature serves as an automatic
reset device for ignition controls locked out because the
burner has failed to light. This type of nuisance lockout is
usually attributedto 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 relight the furnace.
Burner Flame

inch (508 x 635mm) filter for G26Q415-75,
and -125 units.

G26-100

Intake and Exhaust Lines
Check intake and exhaust lines and all connections for
tightness and make sure there is no blockage. Also check
condensate line for free flow during operation.
Insulation
Outdoor piping insulation should be inspected yearly for
deterioration. If necessary, replace with same materials.

Burner Flame - Start burner and allow to operate for a few
minutes to establish normal burning conditions. Check

Winterizing and Condensate
1 - Turn off power to unit.

burner flame by observation. Flame should be predominantly blue and strong in appearance.

Trap Care

2 - Have a shallow pan ready to empty condensate water.
Avoid spilling water into the control box.
3 - Remove clamp from flue assembly and remove boot
or cap. Empty water from cap. Visually inspect bottom
of flue assembly. Replace boot and clamp.
4 - Remove boot from condensate trap and empty water.
Inspect trap then replace boot.

Check burner flame periodically to ensure proper operation.

&WARNING

Cleaning DuralokPlus TM Heat Exchanger
If it is necessary to clean the heat exchanger, follow the procedure below and refer to figure 1 when disassembling the
unit. Use papers or protective covering in front of furnace
while removing heat exchanger assembly.

& CAUTION

1 - Check all wiring for loose connections.

1 - Turn off electrical and gas power supplies to furnace.
2 - Remove upper and lower furnace access panels.
3 - Remove four screws around air intake fittingand lift intake pipe up and away.
4 - Loosen hose clamp securing top of flue transition to
bottom of flue collar. Remove screw securing flue collar to top cap and lift exhaust pipe and flue collar up
and away.
5 - If electrical field make-up box is located inside the unit,
it must be removed.

2 - Check circuit breaker located on unit control box.

6 - Remove gas supply line connected to gas valve.

Annual Service
At the beginning of each heating season, system should be
checked as follows by a qualified service technician:
Electrical

Page 23

Mark all gas valve wires and disconnect them from
valve. Mark and remove wires from flame roll-out
switch.

8 - Remove top cap of unit.
9-

Remove sensor wire from SureLight"
connect 2-pin plug from the ignitor.

control. Dis-

10- Mark and disconnect pressure switch tubing from both
sides of the pressure switch.
11 - Loosen two screws holding gas manifold support at
vestibule panel.
12 - Remove four burner box screws at the vestibule panel
and remove burner box and gas valve/manifold assembly with bracket.
13- Drain condensate trap. Disconnect condensate line
from the outside of unit. Remove condensate line from
condensate trap by turning the adapter fitting counterclockwise. The fitting has standard right-hand
threads.
14 - Disconnect the drain hose from the flue transition to
the elbow on the cold header (collector) box trap.
15 - Disconnect the 2-pin plug from the combustion air inducer at the blower deck. Remove four screws from
combustion air inducer and remove flue transition and
inducer assembly from cabinet. Take care not to lose
the combustion air orifice.
16 - Disconnect 9-pin plug from the blower compartment at
the blower deck.
17 - Remove 9-pin plug above the blower deck.
18 - Remove the limit switch and the pressure switch from
the vestibule panel.
19 - Remove two screws from the front cabinet flange at
the blower deck. Remove front screws from cabinet at
blower deck on left and dght sides. Cabinet sides must
be slightly spread to clear heat exchanger passage.
20- Remove screws along vestibule sides and bottom
which secure vestibule panel and heat exchanger assembly to cabinet. Remove heat exchanger.

28 - Re-install the combustion air inducer. Check the plastic orifice in the inducer inlet to make sure it has not
fallen out. See figure 1. Reconnect the 2-pin plug to
the wire harness. Re-install the flue transition in the
cabinet and re-attach the drain tube. Route the drain
tube below the combustion air inducer housing and to
the elbow on the cold header (collector) box trap. See
figure 36.
29 - Re-install condensate line with adapter to condensate
trap. Use fresh Teflon tape to ensure a leak-free joint.
Re-connect to condensate line outside of the unit.
30 - Re-install the burner box. Tighten the screws holding
the support bracket. It is important that the glass fiber
gasket not be damaged so it will provide a continuous
seal between the burner box and the vestibule panel
31 - With the pressure switch mechanism oriented on the
right, reconnect pressure switch tubing by connecting
the tubing from the burner box to the barbed fitting on
the bottom. Connect the tubing from the combustion
air inducer to the barbed fitting on the top. See figure
36.
32 - Reconnect the sensor and ignitor wires.
33 - Re-install top cap to unit.
34 - Re-instaU electrical connections to gas valve. Orange
wire to M1 and yellow wire to C2. Reconnect wires to
flame roll-out switch.
NOTE - Unit is polarity-sensitive. 120V supply wiring
must be installed correctly.
35 - Reconnect main gas line to gas valve.
36 - Re-install field make-up box if removed.
37 - Re-install exhaust pipe/flue collar and secure flue collar to the unit top cap using existing screw. Insert the
bottom of the flue collar into the top of the flue transition and tighten hose clamp.
38 - Re-install intake pipe fitting to burner box with screws.
39 - Replace both upper and lower access panels.

21- Back wash heat exchanger with soapy water solution
or steam. If steam is used it must be below 275°F
(135°C).

40 - Refer to instruction on verifying gas and electrical connections when re-establishing supply.
41 - Following lighting instructions from installation manual, light and run unit for 5 minutes to ensure heat exchanger is clean, dry and operating safely.

22 - Thoroughly rinse and drain the heat exchanger. Soap
solution can be corrosive so take care that entire assembly is completely rinsed.

Cleaning the Burner Assembly
1 - Turn off electrical and gas power supplies to fumaca.
Remove upper and lower furnace access panels.

23 - Re-install heat exchanger into cabinet making sure
that the clamshells of the heat exchanger assembly
are resting in the notches of the support located at the
rear of the cabinet. This can be viewed by removing
the indoor blower and examining through the blower
opening.
24 - Re-secure the supporting screws along the vestibule
sides and bottom to the cabinet.
25 - Re-install cabinet screws on sides and front flange at
blower deck.
26 - Re-install the limit switch and pressure switch on the
vestibule panel.
27 - Re-install 9-pin plug to blower deck and connect it to
the 9-pin plug from below the blower deck.

2 - Disconnect the gas supply line to gas valve. Depending on gas plumbing installation,the gas manifold may
move aside enough that breaking the union may not
be necessary.
3 - Remove five screws from edges of burner box cover.
G26-50 units have only four screws.
4 - Loosen two screws on bottom of burner box front. The
cover is key holed at these screw point so screws do
not need to be removed. Pull off cover and set aside.
6 - Mark all gas valve wires and disconnect them from
valve.
7 - Mark and disconnect sensor wires from the burner box
at the ignition control. Disconnect 2-pin plug from the
ignitor at the burner box,

Page 24

8 - Loosen two screws at the gas manifold support bracket.
9 - Pull on the left side of the gas manifold and follow with
tension to the right side. The manifold support bracket
will be free of the mounting screws on the vestibule
panel. Set the gas manifold/gas valve assembly aside.
Take care not to damage foam gaskets on each end of
the gas manifold.
10 - Using a 1/4 inch nut driver, remove the burner mounting screws from underneath the burners.
11 - While supporting ignitor and sensor lines at the grommet, grasp burners and simultaneously pull burners
and grommet out of the burner box.
12 - Remove ignitor and sensor bracket assemblies from
burners using a 1/4 inch nut driver to remove two
screws from each bracket.
13 - Clean burner by running a vacuum with a soft brush attachment over face of burners. Visually inspect inside of
burners and crossovers for any blockage caused by foreign matter. Remove any blockage.
14 - Re-install ignitor and sensor bracket assemblies on
burners.
NO TE - Ignitor must be installed on the opposite side of
the burner from the metal button protrusions.
Screws
which attached the ignitor bracket must be installed
from the same side as the ignitor and through the bracket to engage in the smaller holes located in the burner.
The correct burner orientation is with metal button protrusions always pointing up.
15 - Replace burner ignitor assembly back into burner box
so that grommet groove fits back into sheet metal

Page 25

notch and makes a good seal. The bumers sit on top of
the burner box flanges. Make certain that the screws
from the underneath the box pass through the larger
holes in the flange and engage in the smaller holes in
the burner. Re-install the two screws.
16 - Re-install the gas manifold/gas valve assembly by first
inserting the right hand side of the gas manifold into
the burner box. Swing left side of manifold into box
while engaging support bracket to vestibule panel
screws. Check that foam gaskets are providing a seal
around each end of the gas manifold. All gas orifices
should be engaged. If at this point the burners were
mounted in the wrong holes, this needs to be corrected. The saddle brackets on the gas manifold
should be flush with the front surfaces on the burner
box sides.
17 - Inspect the dual layered metal pieces at the front lip of
the cover. These pieces must sandwich around the
metal. Re-install burner box cover.
18 - Re-install the screws to secure the burner box cover.
Make sure screws are tight to ensure a leak tight bumer box. Tighten the two screws underneath the box.
Again, inspect the grommet to ensure a tight seal.
19 - Tighten the two screws holding the manifold bracket to
the vestibule panel.
20 - Re-install the electrical connections to the gas valve.
Orange wire to M1 and yellow wire to C2.
21 - Re-install the 2-pin ignitor plug at the burner box. Reinstall sensor line to ignition control spade connector.
22 - Reconnect gas line to gas valve.
23 - Replace lower access panel.
24 - Following lighting instructions and gas line connection
test procedures from installation manual.
25 - Replace upper access panel.

The following repair parts are available through Lennox dealers. When ordering parts, include the complete fumace model
number listed on the unit rating plate. Example: G26Q3-75.
CABINET PARTS

HEATING PARTS

Cabinet cap
Blower panel
Upper access panel

Heat exchanger/coil assembly
Gas manifold
Main burner orifices
Main burners
Gas valve

CONTROL PANEL PARTS
Surelight" integrated control
Transformer
Circuit breaker
Door interlock switch

Ignitor
Primary limit control
Flame rollout switch
Filter and filter rack assembly
Flue transition
Pressure switch
Flame sensor

BLOWER PARTS
Blower wheel
Motor
Motor mounting frame
Motor capacitor
Blower housing cut-off plate
Blower housing

Sight glass and grommet
Rubber boot trap
Foam manifold gaskets
Combustion air inducer
Condensate pipe plug and adapter
Cold end header (collector) box

DIAGNOSTIC CODES
LED #1
SIMULTANEOUS
SLOW FLASH
SIMULTANEOUS
FAST FLASH
SLOW

FLASH

LED #2
SIMULTANEOUS
SLOW FLASH
SIMULTANEOUS
FAST FLASH

DESCRIPTION
Power on - Normal operation.
Alan _inn_l_d dHrinn t_nnlinn _nd r_nfin=JnH_ fan
Normal operation - signaled when heating demand
thermostat

initiated at

Primary or secondary limit switch open.

OFF

SLOW FLASH

Pressure switch open or has opened 5 times during a single call for heat;
OR: Blocked inlet/exhaust vent; OR: Condensate line blocked;
OR: Pressure switch closed prior to activation of combustion air inducer.

ALTERNATING
SLOW FLASH

Watchguard - burners failed to ignite.

SLOW FLASH

OFF

SLOW FLASH

ON
ON
OFF

ON
OFF
ON

FAST FLASH

SLOW FLASH

Main power polarity reversed. Switch line and neutral.

SLOW FLASH

FAST FLASH

ALTERNATING
FAST FLASH

Low flame signal. Measures below .7 microAmps. Replace flame sense rod.
Improper main ground or line voltage below 75 volts;
OR: Broken ieniter: OR: Oeen ieniter circuit.

Flame sensed without _las valve energized.
Rollout switch open. OR: 9-pin connector improperly attached.
Circuit board failure or control wired incorrectly.

NOTE - Slow flash equals 1 Hz :one flash per second). Fast flash equals 3 Hz (three flashes per second).
Minimum flame sense current = O.15 mieroAmps.

Page 26

SURELIGHT
CONTROL
HEATING
SEQUENCE
OFOPEPu_,TION

NORMALHEATING
MODE

I
I

ABNORMAL

POWERON
I

CONTROL SELF-CHECK

COMBUSTION

AIR INDUCER

GAS VALVE OFE COMBUSTION AIR INDUCER
INDOOR BLOWER ON.
LED #1 ALTERNATING FAST FLASH
NI-NI-NI-NI-NI-NI-NoO
LED#2 ALTERNATING FAST FLASH
CHECK FOR BROKEN IGNITOR OR
OPEN IGNITOR CIRCUIT
I

OKAY?

ON FOR 1 SECOND.

[

L
TURN INDUCER

SECOND.

,sPOLAR,TY
REVERSED?

LED#1 AND LED#2

I.o

ALTERNATING
FASTI
FLASH. SIGNAL

HOLDSUNTILUNITISI_
PROPERLY GROUND.I
g

---_1

ON FOR,

-_1

I
/

[

GAS VALVE OFE COMBUSTION

PROPER GROUND?

ON.

AIR INDUCER OFF.

INDOOR B_EODWERDELAY OFF.

LEDON

(RESET CONTROL

/ _
/
I YES.J ISVOLTAGE
I N° I

ISTHERE

HEATING MODE

BY TURNING

MAIN POWER

OFF.)

POLARITY
REVERSED
LED #1 - FAST FLASH
LED
#2- SLOW
FLASH

ABOVE 75 VOLTS? I_------"l I

YES I
•

ROLLOUT
SWITCH
CLOSED?

wsI

II
I_
_1

I_
BURNER OFF?
(CONTINUOUS FLAME CHECK)

LI_L

I LED#1 AND LED#2 ALTERNATING FAST
FLASH. SIGNAL HOLDS UNTIL VOLTAGE

RISESAEOVE
75VOLTS. I

GAS VALVE OFF. COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER OFF WITH DELAY.
LED #1 - ON. LED #2 - SLOW FLASH.
ROLLOUT SWITCH CLOSES

YES _
LED #1 -- SLOW FLASH
LED #2 -- SLOW FLASH

GAS VALVE OFF. COMBUSTION AIR INDUCER ON.
INDOOR BLOWER ON HEATING SPEED.
LED #1 - SLOW FLASH
LED #2 - OFF

LED #1 - FAST FLASH
THERMOSTAT
FOR HEAT:
LED #2 - CALLS
FAST FLASH

I
I

YES _
IS COMBUSTION

AIR INDUCER

I (HTG ACC TERMINAL

ENERGIZED?

IS ENERGIZED

PRESSURE SWITCH OPEN?
/
YES
IS COMBUSTION

,
,

AIR

WITH C.A.B.)

HAS
COMBUSTION
SWITCH
CLOSED INAIR
2.5 PRESSURE
MINUTES?
YEsYES
/T_

I
I

YES _
CONTINUED

COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER OFF WITH DELAY.

LED #1 OFF
LED #2 SLOW FLASH
(Sequence holds until pressure switch
closes or thermostat resets control.)

5-SECOND COMBUSTION AIR INDUCER PREPURGE
INITIATED BY CLOSED PRESSURE swITCH.

GAS VALVE OFF.

Page 27

GAS VALVE
OFF.BLOWER
COMBUSTION
AIR INDUCER
INDOOR
OFF WITH
DELAY. OFF.
PRESSURE
IS IN
LED #1 SWITCH
- OFF. LED
#2WATCHGUARD
- SLOW FLASH.MODE.
IS 5-MINUTE RESET PERIOD COMPLETE?

[Troub!eshoot!ng
NORMAL

HEATING

MODE

ABNORMAL HEATING MODE

15-SECOND COMBUSTION AIR INDUCER PREPURGE il
[
N T ATED BY CLOSED PRESSURE SW TCH.
j

YES

JN'_O

IS VOLTAGE ABOVE 75 VOLTS?
YES
-1

_t_

IS IGNITOR INTACT AND CONNECTED?_I
IS THERE A PROPER GROUND? I--_1

IGNITOR WARM-UP -- 20 SECONDS.

YEs

yes
4-SECOND TRIAL FOR IGNITION.
GAS VALVE OPENS. IGNITOR IS ENERGIZED
YES

FLAME STABILIZATION

PERIOD.

4 SECONDS J[

]1
_1

I
I

YES _

HAS CONTROL RESET IGNITION
I

SEQUENCE

FOUR TIMES?

I
I
I

IlL:

I
I

YEs

I"
-|
14-----i
I
I
I
YES
_-_-_JNO

INDOOR BLOWER ON DELAY BEGINS
(45 seconds, )
YES

I IGNITION WATCHGUARD MODE, GAS VALVE OFF.
I
COMBUSTION AIR INDUCER OFF.
I
INDOOR BLOWER OFF WITH DELAY
LED 1 ALT. SLOW FLASH LED 2 ALT SLOW FLASH
I
IS 60-MINUTE RESET PERIOD COMPLETE?

FLAME SIGNAL ABOVE 0.7 MICROAMPS?
YES

Nol

GAS VALVE OFF. COMBUSTION AIR INDUCER ON.
NDOOR BLOWER OFF
HAS CONTROL FAILED TO SENSE FLAME FOR
I FIVE CONSECUTIVE TRIES DURING A SINGLE
I
HEAT DEMAND?

]___

FLAME PRESENT?

LEDS SIGNAL
ALTERNATING
FAST FLASH

_ I

I I N°I
I

FLAME RECTIFICATION CURRENT
CHECK, CAN FLAME BE PROVEN WITHIN
4 SECONDS AFTER GAS VALVE OPENS?
( > 0.15 mJcroamps)

YES

GAS VALVE DE-ENERGIZED.
COMBUSTION AIR INDUCER
DE-ENERGIZED. INDOOR BLOWER
ON UNTIL SWITCH CLOSES,LED #1
- SLOW FLASH. LED #2 - ON.
IS LIMIT SWITCH CLOSED?

PRIMARY AND SECONDARY
SWITCHES CLOSED?

(Does nLoOt
a%FctLAoMEr
aS_
oGNoAfLco
nt rol)
LED #1 - SLOW FLASH
LED #2 - FAST FLASH

LIMIT

YES l"
LIMIT SWITCH WATCHGUARD MODE. GAS
VALVE OFF. COMB. AIR
INDUCER OFF. INDOOR
BLOWER OFF WITH
DELAY. LED#I-SLOW
FLASH LED#2 - ON. IS
60MINUTE RESET
PERIOD COMPLETE?

YES f
YES

RESET (CLOSED) WITHIN 3
HAS PRIMARY/SECONDARY
LIMIT
MINUTES?

1
ROLLOUT SWITCH CLOSED?

<- I

SEQUENCE

THERMOSTAT

YES
GAS VALVE DE-ENERGIZED.

DEMAND SATISFIED.

YES
[

HOLDS UNTIL ROLLOUT SWITCH IS RESET

COMBUSTION
SWITCH CLOSED?
AIR PRESSURE
YES

[

COMBUSTION AIR INDUCER POWER OFF.
INDOOR BLOWER OFF WITH DELAY
LED #1GAS
- ON.
LED POWER
#2 - SLOW
VALVE
OFF.FLASH.

YES

LED #1 & #2 SIMULTANEOUS

SLOW FLASHES.

1
I

YES
COMB. AIR INDUCER CONTINUES

5-SECOND

POST PURGE AFTER TSTAT DEMAND tS SATISFIED.
INDOOR AIR BLOWER COMPLETES SELECTED OFF
DELAY BEFORE SHUTTING OFF.

I
I

YES

INDOOR BLOWER OFF WITH DELAY
LED
#1 - OFF. LED
#2 INDUCER
- SLOW FLASH,
I
COMBUSTION
AIR
ON.
HAS CAB SWITCH CLOSED IN 2.5 MINUTES?

5-MINUTE PRESSURE SWITCH
WATCHGUARD MODE.

Page 28

SURELIGHT
CONTROL
COOLING
SEQUENCE
OFOPERATION
NORMALCOOLINGMODE
ABNORMAL
COOLING
MODE
I

POWER ON

IGNITION CONTROL MAIN POWER ON.

CONTROL SELF DIAGNOSTIC CHECK.
IS CONTROL OPERATING NORMALLY?

[

TURN INDUCER ON FOR 1 SECOND.

I
GAS VALVE OFF. COMBUSTION AIR INDUCER OFE
INDOOR BLOWER OFF WITH NORMAL DELAY.
SIGNAL CIRCUIT BOARD FAILURE AT LED.
INTERRUPT MAIN POWER TO RESET CONTROL•

YES JI

IS POLARITY

LED#1 AND LED#2

I
YES
L-_=-z--_l

REVERSED?

r
LED#1 FAST FLASH LED#2 SLOW FLASH ]

NO J,

ALTERNATING FAST
I NO ,
IS THERE
•
FLASH, SIGNAL
_
HOLDS UNTIL UNIT IS _
PROPER GROUND?

I YE&I'

IS VOLTAGE
I_"WlABOVE
75 VOLTS?

N
I_O-_
I<_1

I LED#1 AND LED#2 ALTERNATING FAST
FLASH. SIGNAL HOLDS UNTIL VOLTAGE
RISES ABOVE 75 VOLTS•

PROPERLY GROUND. J

ROLLOUT SWITCH MONITORED CONTINUOUSLY.
IS ROLLOUT SWITCH CLOSED?

GAS VALVE OFF. COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER OFF WITH NORMAL DELAY.
SIGNAL CIRCUIT BOARD FAILURE AT LED,
SEQUENCE

YES_

I
I
I

CHECK FOR MAIN BURNER FLAME SENSE.
IS MAIN BURNER FLAME OFF?

LED: SLOW FLASH RATE REMAINS UNCHANGED
THROUGHOUT COOLING CYCLE.

THERMOSTAT

CALLS FOR COOLING,

€
COMPRESSOR CONTACTOR AND SYSTEM FAN
ENERGIZED WiTH 0-SECOND DELAY, ACB
COOL SPEED TERMINAL IS ENERGIZED. ACC,
TERMINAL IS ENERGfZED.

I
I

€
THERMOSTAT

COMPRESSOR

OPENS•

OFE

€
SYSTEM FAN AND ACC. TERM. OFF
WITH 0_ECOND
DELAY,

Page 29

HOLDS UNTIL ROLLOUT SWITCH CLOSES

GAS VALVE OFF. COMBUSTION AIR INDUCER OFE
INDOOR BLOWER OFF WITH NORMAL DELAY.
SIGNAL CIRCUIT BOARD FAILURE AT LED.
SEQUENCE HOLDS UNTIL FLAME IS NOT SENSED.

SURELIGHT
CONTROL
CONTINUOUS
FANSEQUENCE
OFOPERATION
LED: SLOW FLASH RATE REMAINS
UNCHANGED THROUGHOUT SEQUENCE.

MANUAL FAN SELECTION MADE AT THERMOSTAT.
CONTROL (G) ENERGIZES INDOOR BLOWER AT
ACB LOW SPEED. ACC. TERM. IS ENERGIZED.

THERMOSTAT

CALLS FOR HEAT (W}.

NO
I

THERMOSTAT

YES

CALLS FOR COOLING.

HTG ACC. TERM. ENERGIZES
WITH COMB. AIR INDUCER.

INDOOR BLOWER SWITCHES TO ACB HEAT
SPEED AFTER NORMAL DELAY.

_YES
IINDOOR

]_1_
/

BLOWER SWITCHES TO ACS COOL SPEED. I
THERMOSTAT OPENS. COMBUSTION AIR INDUCER
AND HTG ACC. TERMINAL ARE DE-ENERGIZED.

THERMOSTAT

OPENS.

INDOOR BLOWER SELECTED TIME OFF DELAY BEGINS.
AFTER DELAY ACB HEAT SPEED DE-ENERGIZED.
(blower remains energized during continuous fan mode).

INDOOR BLOWER SWITCHES TO ACB LOW
SPEED. ACC. TERM. REMAINS ENERGIZED.

Page 30

START-UP AND PERFORMANCE

CHECK LIST

JobName

Job No.

Date

Job Location

City

State

Installer

City

State

Unit Model No.

Technician

Serial No.
HEATING SECTION
Electrical Connections Tight? 17
Supply Voltage

Blower Motor H.P.

Blower Motor Amps

Gas Piping Connections
Tight & Leak-Tested? [--7

Fuel Type: Natural Gas? []

LP/Propane Gas? []

Furnace Btu Input
Line Pressure
Regulator Pressure: __

w.c. --

Nat.; __

w.c. -- LP/Propane

Flue Connections Tight? []
Fan Control Setting (45 Seconds Fixed On)
Fan Control Off Setting

Temperature Rise

Filter Clean & Secure? [_1

Vent Clear?
THERMOSTAT

Heat Anticipator Properly Set?

[]

Page 31

Level? []

Source Exif Data:

File Type                       : PDF
File Type Extension             : pdf
MIME Type                       : application/pdf
PDF Version                     : 1.2
Linearized                      : No
Page Count                      : 31
Page Layout                     : SinglePage
Page Mode                       : UseNone
Producer                        : Goby Monitor Application version 3, 2, 1, 4
Create Date                     : Fri Apr 20 14:19:54 2007
Author                          : 
Title                           : 
Subject                         :

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LENNOX Furnace/Heater, Gas Manual L0406249

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