Page 1
.
2000 Lennox Industries Inc.
Dallas, Texas,USA
504,121M
5/2000
£
G50UH(X)
SERIES
GAS FURNACE
Iftheinformationin thismanual is notfollowed
exactly, a fire or explosion may result causing
property damage, personal injury or loss of
life.
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.
05/00
$
Litho U.S.A.
WARNING
WHAT TO DO IF YOU SMELL GAS:
-
Do not try to light any appliance.
-
Extinguish any open flames.
-
Do not touch any electrical switch; d o not use any
phone in your building.
-
Immediatelycall your gassupplier from aneighbor’s
phone. Follow the gas supplier’s instructions.
-
Ifyou cannotreachyour gas supplier,call thefire department.
504,121M
$!
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G50UH(X) Parts Identification
TOP CAP
DURALOKTMHEAT
EXCHANGER
ASSEMBLY
FLUE
COLLAR
COMBUSTION AIR
INDUCER
UPPER ACCESS
PANEL
BURNERS
SURELIGHT
CONTROL BOARD
Z
Z
COMBUSTION AIR
PROVING
(PRESSURE) SWITCH
CABINET
GAS
VALVE
GAS
MANIFOLD
NAMEPLATE
BLOWER
MOTOR
BLOWER ACCESS
PANEL
FIGURE 1
WARNING
Product contains fiberglass wool.
Disturbing the insulation in this product during
installation, maintenance, or repair will expose you
to fiberglass wool. Breathing this may cause lung
cancer.(Fiberglasswool is known to the Stateof California to cause cancer.)
Fiberglass wool may also cause respiratory, skin,
and eye irritation.
To reduce exposure to this substance or for further
information, consult material safety data sheets
availablefromaddressshownbelow,orcontactyour
supervisor.
Lennox Industries Inc.
P.O. Box 799900
Dallas, TX 75379-9900
NOTE - This manual must be left with the equipment
user.
CONTROL BOX
WARNING
Do not set thermostat below 60°F (16°C) in heating
mode. Setting thermostat below 60°F (16°C) reduces
the number of heating cycles. Damage to the unit
may occur that is not covered by the warranty.
WARNING
Ifoverheatingoccursorifgassupply fails toshutoff,
shutoff the manualgas valvetothe appliancebefore
shutting off electrical supply.
CAUTION
Before attempting to perform any service or maintenance, turn the electrical power to unit OFF at the
disconnect switch.
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WARNING
Do not use this furnace if any part has been under
water.Immediatelycall a qualified service technician
to inspect the furnace and to replace any part of the
control system and any gas control which has been
under water.
Your furnace is a gas appliance.
supplied to the unit be completely burned to avoid the production of carbon monoxide gas. Complete combustion of
the gas requires, but is not limited to, correct gas pressure
and gas flow rate, adequate combustion air and proper
venting.
It is critical that the gas
IMPORTANT
Any additions, changes, or conversions required in
order for the appliance to satisfactorily meet the application needs must be made by a Lennox service
technician using factory specified and approved
parts.
WARNING
Improperinstallation,adjustment,alteration,service
ormaintenancecan causepropertydamage,personal injury or loss of life. Installation and service must
be performed by a qualified installer, service agency
or the gas supplier.
Important Directions
1 - Keep the furnace area clear and free of combustible
material, gasoline, and other flammable vapors and
liquids.If itis installedinan insulatedarea, thefurnace
mustbe keptfree ofinsulating material.Insulatingmaterial may be combustible.
DO NOT
2-
unobstructed flow of combustion and ventilating air.
DO NOT
3-
or introduce these products into the combustion air.
These products can cause furnace corrosion.
DONOTdrawreturnairfroma room wherethis fur-
4-
nace, or any other gas appliance (ie., a water heater),isinstalled.
anegative pressure is created inthe room.If a gasappliance is operating in a room with negative pressure,
the flue products can be pulled back down the vent
pipe and into the room. This reverse flow of the flue
gas may result in incomplete combustion and the
formation of carbon monoxide gas. This toxic gas
might then be distributed throughout the house by the
furnace duct system.
The blower door must be securely in place when the
blowerand burners are operating.Gas fumes, which
could contain carbon monoxide, can be drawn into
the living space resulting in personal injury ordeath.
obstruct air flow to unit. Unit must receive an
store chlorine or fluorine products near unit
Whenreturnairisdrawn fromaroom,
WARNING
WARNING
Carbon monoxide gas is invisible, odorless, and
toxic.
Exposure to carbon monoxide 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)
hasthe potentialtoproduce carbonmonoxide gas.Because
Lennoxrecommendsthe use ofa carbon monox-
ofthis,
ide detector in your home, even if you do not own gas
appliances.
retail prices. Contact your Lennox dealer for more details
about this investment in your safety.
Yourfurnace is designed tomeet standardsset by national agencies. It should operate safely when properly
installed and maintained. However, the unit’s performance can be greatly impac ted b y the individual installation andthe operating environment. It is your responsibility to ensure that this appliance is maintained. Proper
maintenanceis criticalfor your s afety and thesatisfactory
operationoftheproduct.
annualinspectionandmaintenanceof thisappliance.
Contact y our Lennox dealer f or an inspection by a qualified serv ic e technician.
Reliable detectors are available at reasonable
Lennoxstronglyrecommends
Lighting Information & Operation
WARNING
If you do not follow these instructions exactly, a fire
or explosion may result causing property damage,
personal injury or death.
BEFORE LIGHTING
forgas.Besuretosmellnext tothefloorbecausesomegas
is heavier than air and will settle on the floor.
smell all around the appliance area
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The gas valve on the G50UH(X) is equipped with either a
gas control knob or lever. Use only your hand to turn t he
gas c ontrol knob or push thegas lever.Never use tools. If
theknobor leverwill notmoveby hand,do not tryto repair
it. Call a qualified service tec hnician. Force or attempted
repair may result in a fire or ex plosion.
Placing the G50UH(X) furnace into operation:
G50UH(X) units are equipped with a SureLightZignition
system.Do
not
attempt to manually light burners on these
furnaces. Eachtime thethermostat calls for heat,the burners will automatically light. The ignitor does not get hot
when there is no call for heat on units with the SureLight
Z
ignitionsystem.
Operating the Gas Valve (Figures 3,4and 5)
STOP
1-
!Read the safety information at the beginning of
this section.
2 - Set the thermostat to the lowest setting. See figure 2.
3 - Turn off all electrical power to the unit.
White Rodgers 36E Series Gas Valve
MANIFOLD
PRESSURE
ADJUSTMENT
SCREW
MANIFOLD
PRESSURE
OUTLET
GAS VALVE SHOWN IN OFF POSITION
FIGURE 3
White Rodgers 36F Series Gas Valve
MANIFOLD
PRESSURE
ADJUSTMENT
SCREW
MANIFOLD
PRESSURE
OUTLET
THERMOSTATS
FIGURE 2
4 - This furnace is equipped with an ignition device which
automatically lights the burners. Do
not
try to light the
burners by hand.
5 - Remove the upper access panel.
White Rodgers 36E/36F Gas Valve -
6-
valve lev er to
OFF
.Seefigure 3for theWhiteRodg-
Switch gas
ers 36E valve and figure 4 for the W hite Rodgers
36F valve.
Honeywell VR8205 G as Valve -
valveclock wis e
to
OFF
Turn knob on gas
.D onotforce.Seefigure
5.
7 - Waitfive minutesto clear outany gas. Ifyou thensmell
STOP
gas,
! 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.
WhiteRodgers 36E/36F Gas Valve-
8-
Switch gas valve lever toON. See figur e 3 for the White Rodgers 36E
valveand figure4 forthe WhiteRodgers 36Fv alve.
Honeywell VR8205 Gas Valve -
counterclockwise
toON. Do not force.
Turn knob on gas valve
GAS VALVE SHOWN IN OFF POSITION
FIGURE 4
Honeywell VR8205 Series Gas Valve
MANIFOLD
PRESSURE
ADJUSTMENT
SCREW
ON
OFF
GAS VALVE SHOWN IN OFF POSITION
MANIFOLD
PRESSURE
OUTLET
FIGURE 5
9 - Replace the upper access panel.
10 - Turn on all electrical power to to the unit.
11 - Set the thermostat to desired setting.
NOTE - When unit is initially started, steps 1 through 11
may need to be repeated to purge air from gas line.
12 - If the appliance will not operate, follow the instructions
“TurningOffGasto theUnit” andcall yourservicetechnician or gas supplier.
Turning Off Gas to the Unit
1 - Set the thermostat to the lowest setting.
2 - Turn off all electrical power tothe unit if service is to be
performed.
3 - Remove the upper access panel.
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4-
White Rodgers 36E/36F Gas Valve -
valve lev er t o
OFF
.
Honeywell VR8205 G as Valve -
OFF
valve clockwis e
5 - Replace the upper access panel.
to
.Donotforce.
Switch gas
Turn knob on gas
Filters
This unit is not equipped with a filter or rack. A field-provided, high-velocity filter is required to ensure proper unit
operation.
A filter must be in place any time the unit is operating.
Seasonal Inspections
A qualified service technician should inspect the complete
system each season (heating and cooling). The following
maintenance procedures should only be conducted by a
qualified service technician.
the unit in any way.
Venting System
Do not attempt to service
WARNING
Asphyxiation Hazard
The exhaust vent for this furnace must be securely
connected to the furnace flue collar at all times.
For your safety and to fulfill the terms of the limited
warranty,aqualifiedservicetechnicianmustannually inspect this furnace and its vent system.
Annually (before heating season) inspect furnace venting
system, vent cap, heat exchanger and burners for corrosion, deterioration, or deposits of debris. Remove any obstructions.
Inspect thefurnace venting system to make sure it is in
place, physically sound and without holes, corrosion, or
blockage. The vent c onnec tor must be correctly positioned and sloped upward. The v ent connector must be
physically s ound, without holes or excessive corrosion.
Inspect the furnace return air duct connection. The duct
mustbesealedtothe furnaceandit mustterminateoutside
the space containing the furnace.
Inspect the physical support of the furnace to guarantee
that it is sound. The support must not sag and must not
have cracks or gaps around thebaseof the furnace. There
must be a seal between the furnace base and the support.
During a seasonal check, the service technician will inspect the indoor blower and the burner flames along with
the venting system.
Blower
Check blower wheel for any debris and clean it, if necessary.Theblowermotor is pre-lubricatedfor extendedbearing life. No further lubrication is needed.
Burner Flame
CAUTION
To ensure proper operation, a qualified technician
should annually check the burner flame.
Service Reminder
Callyour Lennox service technician if the unitwill not operate. Before calling, always check the following to be sure
service is required.
1 - Check that electrical disconnect switches are
2 - Check room thermostat for proper setting.
3 - Replace any blown fuses or reset circuit breakers.
4 - Gas valve should beON.
5 - Air filter should not be plugged, which wil limit air flow.
6 - Is gas turned on at meter?
7 - Is manual main shut-off valve open?
Record themodel and serialnumber of the furnace. These
numbersare on theunit nameplate,which is locatedbelow
the burners.
Serial Number ________________________________
Model Number ________________________________
Safety Precautions
If you discover any of the following, shut down your
unitand contact aLennoxdealerfor an inspectionbya
qualified technician.
-
If you repeatedly hear any new or unfamiliar sounds
whileyourunit is operating,there maybeaproblem. For
example, poorly performing burners can produce unfamiliar noises.
-
Ifyou smellany unusualodors, yourunit maybe operating improperly.For example, units can give off unfamiliar odors if components are required to operate in abnormal conditions.
-
Lookforvisiblesignsof amalfunctioning unit.Examples
includeunusual amounts ofcondensate on windowsinside your house, visibly burnt components or unusual
dirt or rust accumulations on the vent pipe or in the unit.
-
If you experience headache, nausea, fatigue, or dizziness, thecausecouldbe exposure to carbon monoxide
gas. This is often misdiagnosed as the flu because
symptoms are similar. If 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.
ON.
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Planned Service
Youshould expecta service technician tocheck the following items during an annual inspection. Power to the unit
must be shut off for the service technician’s safety.
Fresh air grilles and louvers
where the furnace is installed) - Must be open and unobstructed to provide combustion air.
(on the unit and in the room
Return air duct
an air seal to the unit.
Operating performance
operationtomonitorproperperformanceof theunitandthe
vent system.
Combustion gases
compared to the unit specifications.
- Must be properly attached and provide
- Unit must be observed during
-Flue products mustbe analyzed and
Burners
Vent pipe
or sagging pipe, or disconnected joints.
Unit appearance
of water, burnt or damaged wires, or components.
Blower access door
vide a seal between the return air and the room where the
furnace is installed.
- Must be inspected for rust, dirt, or signs of water.
-Mustbe inspected for signsof water,damaged
- Must be inspected for rust, dirt, signs
- Must be properly in place and pro-
Problems detected during the inspection may make it necessary to temporarily shut down the furnace untilthe items
can be repaired or replaced.
Pay attention to your furnace.
tweenannualfurnace inspections thatmay resultin unsafe
operation.For instance, itemsinnocently stored nextto the
furnacemay obstruct thecombustionair supply.This could
cause incomplete combustion and the production of carbon monoxide gas.
Situations can arise be-
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