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3DJH 

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. (Fiberglass wool is known to the State of
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
available from address shown below, or contact
your supervisor.

Lennox Industries Inc.
P.O. Box 799900
Dallas, TX 75379-9900

WARNING

Do not use this furnace if any part has been under
water. Immediately call a qualified service techni-
cian to inspect the furnace and to replace any part
of the control system and any gas control which
has been under water.

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.

IMPORTANT

Any additions, changes, or conversions required
in order for the appliance to satisfactory meet the
application needs must be made by a Lennox ser-
vice technician using factory specified and ap-
proved parts.

CAUTION

Before attempting to perform any service or main-
tenance, turn the electrical power to unit OFF at
disconnect switch.

IMPORTANT DIRECTIONS

1- Keep the furnace area clear and free of combustible

material, gasoline, and other flammable vapors and liq-
uids. If installed in an insulated area, furnace must be
kept free of insulating material. Insulating material may
be combustible. Inspect furnace venting system to
make sure it is in place, physically sound, and without

holes, corrosion, or blockage. Inspect furnace return
air duct connection to ensure duct is sealed to the fur-
nace and terminates outside the space containing the
furnace. Inspect 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.

2- DO NOT obstruct air flow to unit. Unit must receive an

unobstructed flow of combustion and ventilating 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 draw return air from a room where this

furnace, or any other gas appliance (ie., a water
heater), is installed. 
When return air is drawn from
a room, a negative pressure is created in the room. If
a gas appliance is operating in a room with negative
pressure, the flue products can be pulled back down
the vent pipe and into the room. This reverse flow of
the flue gas may result in incomplete combustion
and the formation of carbon monoxide gas. This toxic
gas might then be distributed throughout the house
by the furnace duct system.

Your furnace is a gas appliance. It is critical that the gas

supplied to the unit be completely burned to avoid the pro-

duction of carbon monoxide gas. Complete combustion

of the gas requires, but is not limited to, correct gas pres-

sure and gas flow rate, adequate combustion, air, and
proper venting.

WARNING

Carbon monoxide gas is invisible, odorless, and
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 fire-

places) has the potential to produce carbon monoxide

gas. Because of this, Lennox recommends the use

of a carbon monoxide detector in your home, even
if you do not own gas appliances. 
Reliable detectors

are available at reasonable retail prices. Contact your

independent Lennox dealer for more details about this

investment in your safety.

Your furnace is designed to meet standards set by nation-
al agencies, and to operate safely when properly installed

and maintained. However, the unit’s performance can be

greatly impacted by the individual installation and the op-

erating environment. It is your responsibility to ensure

that this appliance is maintained. Proper maintenance is

critical for your safety and the satisfactory operation of the

Summary of Contents for G20 Series

Page 1: ...witch 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 Extinguish any open flames Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other appliance If the information in this manual is not followed exac...

Page 2: ...DRAFT HOOD UPPER ACCESS PANEL 851 56 BURNER BOX IGNITION CONTROL 2 5 GAS MANIFOLD BURNER BOX DAMPER ASSEMBLY 5 5 TOP STRIP LIMIT CONTROL 1 7 21752 2 ROLL OUT SWITCH BLOCKED VENT SHUT OFF SWITCH 1 7 3 6 9 9 PILOT ELECTRODE ASSEMBLY REMOVABLE BURNER BOX TOP ...

Page 3: ...s seal between base and support 2 DO NOT obstruct air flow to unit Unit must receive an unobstructed flow of combustion and ventilating 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 draw return air from a room where this furnace or any other gas appliance ie a water heater is instal...

Page 4: ...his appliance is equipped with an ignition device which automatically lights the pilot Do not try to light the pilot by hand 5 Remove control access panel 6 Honeywell VR8204 Gas Valve Turn the knob on the gas valve clockwise to OFF See figure 3 Robertshaw 7200 Gas Valve Depress the lever and move to OFF position Do not force See figure 4 ON OFF FIGURE 3 21 95 6 5 6 6 9 9 GAS VALVE SHOWN IN OFF POS...

Page 5: ...ion is needed Pilot and Burner Flame CAUTION Check pilot flame and burner flame periodically to ensure proper operation 1 Pilot Flame Pilot flame must surround the end of flame sensor for proper operation of pilot safety cir cuit See figure 7 PILOT FLAME Side View BURNER PILOT GAS LINE ELECTRODE G20E G20X FIGURE 7 FLAME SENSOR 2 Burner Flame Start burner and allow to operate for a few minutes to e...

Page 6: ...iagnosed as the flu because symptoms are similar If you suffer from flu like symp toms that are exaggerated at home but seem to sub side 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 inv...

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