Lennox G26 Series Guide

Page 1
11/00
*2P1100*
503,533M
*P503533M*
G26
SERIES
Litho U.S.A.
503,533M
9/98
Supersedes 1/97
WHAT TO DO IF YOU SMELL GAS:
If the information in this manual is not
followe exactly, a fire or explosion
may result causing property amage,
personal injury or loss of life.
WARNING
Do not store or use gasoline or other
flammable vapors an liqui s in the
vicinity of this or any other appliance.
Installation an service must be perĆ
forme by a qualifie installer, service
agency or the gas supplier.
DDo not try to light any appliance.
DDo not touch any electrical switch; o not
use any phone in your buil ing.
DImme iately call your gas supplier from a
neighbor's phone. Follow the gas suppliĆ
er's instructions.
DIf you cannot reach your gas supplier, call
the fire epartment.
DExtinguish any open flames.
GAS FURNACE
E1997 Lennox ndustries nc.
Dallas, Texas


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G26 PARTS IDENTIFICATION
FIGURE 1
HEAT
EXCHANGER
ASSEMBLY
UPPER ACCESS
PANEL
BURNERS
BURNER
BOX
SURELIGHT
INTEGRATED
CONTROL BLOWER
MOTOR
GAS
MANIFOLD
FRESH AIR INTAKE
CONNECTION
CABINET
CONTROL
BOX
GAS
VALVE
CONDENSATE
TRAP
COMBUSTION AIR
PROVING
(PRESSURE)
SWITCH
COMBUSTION AIR
BLOWER
BLOWER ACCESS
DOOR
DOOR
INTERLOCK
SWITCH
FLUE COLLAR
TOP CAP
FLAME
SIGHT
GLASS

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WARNING
Pro uct contains fiberglass wool.
Disturbing the insulation in this pro uct uring
installation, maintenance, or repair will expose
you to fiberglass wool. Breathing this may
cause lung cancer. (Fiberglass wool is known to
the State of California to cause cancer.)
Fiberglass wool may also cause respiratory,
skin, an eye irritation.
To re uce exposure to this substance or for furĆ
ther information, consult material safety ata
sheets available from a ress shown below, or
contact your supervisor.
Lennox In ustries Inc.
P.O. Box 799900
Dallas, TX 75379-9900
WARNING
Do not set thermostat below 60_F (16_C) in heatĆ
ing mo e. Setting thermostat below 60_F (16_C)
re uces the number of heating cycles. Damage
to the unit may occur that is not covere by the
warranty.
WARNING
If overheating occurs or if gas supply fails to shut
off, shut off the manual gas valve to the appliance
before shutting off electrical supply.
WARNING
Do not use this furnace if any part has been
un erwater. Imme iately call a qualifie service
technician to inspect the furnace an to replace
any part of the control system an any gas conĆ
trol which has been un er water.
CAUTION
Before attempting to perform any service or
maintenance, turn the electrical power to unit
OFF at isconnect switch.
IMPORTANT
Any a itions, changes, or conversions require
in or er for the appliance to satisfactorily meet
the application nee s must be ma e by a Lennox
service technician using factory specifie an
approve parts.
IMPORTANT DIRECTIONS
1 - Keep the furnace area clear and free of combustible
material, gasoline, and other flammable vapors and
liquids. f installed in an insulated area, furnace must
be kept free of insulating material. nsulating material
may be combustible.
2 - DO NOT obstruct air flow to unit. Unit must receive
an unobstructed flow of combustion and ventilatĆ
ing air.
3 - DO NOT store chlorine or fluorine products near unit
or introduce these products into the combustion air.
These products can cause furnace corrosion.
4 - DO NOT raw the return air from a room where
another gas appliance (ie., a water heater) is
installe . Even though this furnace draws its comĆ
bustion 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. f 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 distribĆ
uted through the house by the furnace duct system.
Your furnace is a gas appliance. t is critical that the gas
supplied to the unit be completely burned to avoid the proĆ
duction of carbon monoxide gas. Complete combustion
of the gas requires, but is not limited to, correct gas presĆ
sure and gas flow rate, adequate combustion, air, and
proper venting.
WARNING
Carbon monoxi e gas is invisible, o orless, an
toxic.
Exposure to this gas can cause personal injury and even
death to all occupants, including pets. Any item that is
powered by or gives off heat from a combustion process
(including lawn mowers, automobiles, and fireplaces)
has the potential to produce carbon monoxide gas. BeĆ
cause of this, Lennox recommen s the use of a carĆ
bon monoxi e etector in your home, even if you o
not own gas appliances. Reliable detectors are availĆ
able at reasonable retail prices. Contact your indepenĆ
dent Lennox dealer for more details about this investĆ
ment in your safety.
Your furnace is designed to meet standards set by naĆ
tional agencies, and to operate safely when properly
installed and maintained. However, the unit's perforĆ
mance can be greatly impacted by the individual installaĆ
tion and the operating environment. t is your responsiĆ

Page 4
bility to ensure that this appliance is maintained. Proper
maintenance is critical for your safety and the satisfactoĆ
ry operation of the product. Lennox strongly recomĆ
men s annual inspection an maintenance of this
appliance. Contact your independent Lennox dealer for
an inspection by a qualified service technician.
LIGHTING INFORMATION AND OPERATION
WARNING
If you o not follow these instructions exactly, a
fire or explosion may result causing property
amage, personal injury or loss of life.
BEFORE L GHT NG 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.
Unit may be equipped with either a gas control knob or
lever. Use only your hand to push in or turn the gas conĆ
trol knob or move the gas control lever. Never use tools.
f 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.
To place G26 furnace into operation:
G26 units are equipped with a SureLight ignition system.
Do not attempt to manually light these furnaces. Each
time thermostat calls for heat, the burners will be automatĆ
ically lit by the ignitor. The ignitor does not get hot when
there is no call for heat on units with the SureLight ignition
system.
Gas Valve Operation (Figure 3)
1 - STOP! Read the safety information at the beginning
of this section.
2 - Set thermostat to lowest setting. See figure 2.
THERMOSTATS
FIGURE 2
3 - Turn off all electrical power to appliance.
4 - This appliance s equipped with an ignition device
which automatically lights the burners. Do not try to
light the burners by hand.
5 - Remove upper access panel.
ON
OFF
HONEYWELL VR8204 SERIES GAS VALVE
GAS VALVE SHOWN IN OFF POSITION
WHITE RODGERS
36E GAS VALVE
GAS VALVE
SHOWN
IN OFF
POSITION
FIGURE 3
6 - On Honeywell VR8204 gas valves, turn knob on gas
valve clockwise to OFF. For White Rodgers 36E
gas valves, move switch to OFF. Do not force. See
figure 3.
7 - Wait fifteen (15) minutes to clear out any gas. f you
then smell gas, STOP! mmediately call your gas
supplier from a neighbor's phone. Follow the gas
supplier's instructions. f you do not smell gas go to
next step.
8 - For Honeywell VR8204 gas valves, turn knob on gas
valve counterclockwise to ON. For White RodgĆ
ers 36E gas valves, move switch to ON.
9 - Replace upper access panel.
10 - Turn on all electrical power to unit.
11 - Set thermostat to desired setting.
NOTE - When unit is first started, steps 1 through 11 may
need to be repeated to purge air from line.
12 - f the appliance still will not operate, follow the inĆ
structions To Turn Off Gas To Unit" and call your serĆ
vice technician or gas supplier.
To Turn Off Gas To Unit
1 - Set thermostat to lowest setting.
2 - Turn off all electrical power to unit if service is to be
performed.
3 - Remove upper access panel.
4 - On Honeywell VR8204 gas valves, turn knob on gas
valve clockwise to OFF. For White Rodgers 36E
gas valves, move switch to OFF. Do not force.
5 - Replace upper access panel.

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FILTERS
A filter must be in place any time the unit is in operation.
The filter may be located in the unit (optional kit) or
installed in a return air grille. Ask your dealer to show
you the filter location. The filter should be inspected
monthly and cleaned when necessary to assure proper
furnace operation.
Filters used inside the G26 series unit are available from
Lennox and must be ordered separately. These foam filĆ
ters may be cleaned for reuse. f replacement is necesĆ
sary, order Lennox part no. 31J81 for 14 X 25 inch filter
for G26Q2-50, Q3-50 and Q3-75 units and P-8-7831 for
20 X 25 inch filter used with G26Q4/5-75 and all sizes of
G26-100 and -125 units. Use the following procedure to
clean filter. Refer to figure 1.
In-Unit Filter with Bottom Return Air
1 - Turn off electric power to furnace.
2 - Remove blower access panel.
3 - Remove filter by pressing side filter clips and pulling
filter up and out. See figure 4.
FIGURE 4
BOTTOM RETURN FILTER INSTALLATION
FURNACE
BASE BOTTOM
REAR FILTER CLIP
RETURN AIR OPENING
SIDE FILTER CLIPS (2)
FURNACE
FRONT
FURNACE
BACK
4 - Clean filter with cold water and a mild soap. Direct
water through filter in the opposite direction of air
flow. Remove all soap residue.
5 - Allow filter to dry then spray with filter handicoater
(P-8-5069), available from your Lennox dealer, prior
to reinstallation.
6 - Place filter in bottom of blower compartment beĆ
neath rear filter clip. Press down on filter sides. Filter
clips flex, allowing filter to snap into place.
7 - Replace blower access panel.
WARNING
Blower oor must be securely in place when
blower an burners are operating. Gas fumes,
which coul contain carbon monoxi e, can be
rawn into living space resulting in personal injuĆ
ry or eath.
Si e Return Air Filter (See Figure 5)
1 - Turn off electric power to furnace.
2 - Locate the filter door of the filter rack assembly.
3 - Using the filter door pins, pull filter door, with filter atĆ
tached, out of filter rack assembly. Remove filter door
from filter by pulling up on securing tabs.
4 - Clean filter with cold water and a mild soap. Direct
water through filter in the opposite direction of air
flow. Allow filter to dry, then spray with filter handiĆ
coater, available from your Lennox dealer, prior to reĆ
installation.
5 - Position filter door on end of filter so that the thumb
tab side of the filter door is away from the furnace.
Check for correct air flow position. Squeeze thumb
tabs to secure filter to door.
6 - Guide filter and filter door into the filter rack
installed on side of furnace. Push door into filter
rack until secure.
FIGURE 5
REMOVING / REPLACING FILTER DOOR
FILTER DOOR FILTER
FILTER DOOR
PIN
TAB
TAB
FILTER DOOR
PIN
SEASONAL INSPECTIONS
A qualified service technician should inspect the comĆ
plete system each season (heating and cooling). The folĆ
lowing maintenance procedures should be conducted
by a qualified service technician. Do not attempt to serĆ
vice the unit in any way.
During a seasonal check the service technician will inĆ
spect the indoor blower, the burner flame and the venting
system.
Venting System
Annually (before heating season) inspect furnace ventĆ
ing system, heat exchanger and burners for corrosion,
deterioration, or deposits of debris. Remove any obĆ
structions.
nspect furnace venting system to make sure it is in
place, physically sound, and without holes, corrosion, or
blockage. Vent connector must be in correct position,
sloped upward and be physically sound without holes or
excessive corrosion.
nspect furnace return air duct connection to ensure duct
is sealed to the furnace and terminates outside the
space containing the furnace.

Page 6
nspect the physical support of the furnace to guarantee
that it is sound without sagging, cracks or gaps around
base and it maintains seal between base and support.
nspect and clean the condensate traps and drain.
Blower
Check and clean blower wheel for any debris. Blower
motor is pre-lubricated for extended bearing life. No furĆ
ther lubrication is needed.
Burner Flame
CAUTION
Using flame sight glass, check burner flame
perio ically to ensure proper operation.
Burner Flame -- Start burner and allow to operate for a few
minutes to establish normal burning conditions. Check burnĆ
er flame by observation. Flame should be predominantly
blue in color and strong in appearance.
Contact your Lennox dealer for a periodic unit inspection by a
qualified service technician.
SERVICE REMINDER
Call your Lennox service technician if unit is inoperative.
Before calling, always check the following to be sure serĆ
vice is required.
1 - Check that electrical disconnect switches are ON.
2 - Check room thermostat for proper setting.
3 - Replace any blown fuses or reset circuit breakers.
4 - Gas valve should be ON.
5 - Air filter should not be plugged limiting air flow.
6 - s gas turned on at meter?
7 - s manual main shutĆoff valve open?
SAFETY PRECAUTIONS
If you iscover any of the following, shut own your
unit, an contact an in epen ent Lennox ealer for
an inspection by a qualifie technician.
Df you repeatedly hear any new or unfamiliar sounds
while your unit is operating, there may be a problem.
For example, poorly performing burners can produce
unfamiliar noises.
Df you smell any unusual odors, your unit may be operĆ
ating improperly. For example, units can give off unfaĆ
miliar odors if components are required to operate in
abnormal conditions.
DLook for visible signs of a malfunctioning unit. ExamĆ
ples include unusual amounts of condensate on winĆ
dows inside your house, visibly burnt components or
unusual dirt or rust accumulations on the vent pipe or
in the unit.
Df you experience headache, nausea, fatigue, or dizziĆ
ness, the cause could be exposure to carbon monoxĆ
ide gas. This is often misdiagnosed as influenza beĆ
cause symptoms are similar. f you suffer from flu-like
symptoms that are exaggerated at home, but seem to
subside while you are away from the house, exposure
to carbon monoxide could be the cause.
Your vigilance may pay off in early detection of a problem
before either personal injury or property damage occurs.
Do not hesitate to contact a qualified service technician
as an investment in your well being.
PLANNED SERVICE
You should expect a service technician to check the folĆ
lowing items during an annual inspection. Power to the
unit must be shut off for the service technician's safety.
Fresh air grilles an louvers (on the unit and in the room
where the furnace is installed) -- Must be open and unobĆ
structed to provide combustion air.
Burners -- Must be inspected for rust, dirt, or signs of waĆ
ter.
Vent pipe -- Must be inspected for dirt, signs of water,
damaged or sagging unsupported pipe, or disconnected
joints.
Unit appearance -- Must be inspected for rust, dirt, signs
of water, burnt or damaged wires, or components.
Blower access oor -- Must be properly in place and proĆ
vide a seal between the return air and the room where the
furnace is installed.
Return air uct -- Must be properly attached and provide
an airtight seal to the unit.
Operating performance -- Unit must be observed during
operation to monitor proper performance of the unit and
the vent system.
Combustion gases - Flue products must be analyzed
and compared to the unit specifications.
Problems detected during the inspection may make it
necessary to temporarily shut down the furnace until the
items can be repaired or replaced.
Pay attention to your furnace. Situations can arise beĆ
tween annual furnace inspections that may result in unĆ
safe operation. For instance, items innocently stored next
to the furnace may obstruct the combustion air supply.
This could cause incomplete combustion and the producĆ
tion of carbon monoxide gas.