Page 1
PRODUCT LITERATURE
1993 Lennox Industries Inc.
Dallas, Texas
503,069M
11/93
Supersedes 502,893M
80MGF
SERIES
GAS FURNACE
RETAIN THESE INSTRUCTIONS
FOR FUTURE REFERENCE
If the information in this manual is not
followed 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 perĆ
formed by a qualified installer, serĆ
vice agency or the gas supplier.
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; 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.
Page 1
Page 2
80MGF PARTS IDENTIFICATION
1
2
3
4
5
6
7
UPFLOW POSITION DOWNFLOW POSITION
1 - COMBUSTION AIR
BLOWER
2 - PRESSURE SWITCH
3 - GAS VALVE
4 - ROLLOUT SWITCH
(One on each side)
5 - BURNERS
6 - CONTROL BOARD
7 - BLOWER
7
6
1
2
3
4
5
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 furĆ
ther 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
If overheating occurs or if gas supply fails to
shut off, shut off the manual gas valve to the apĆ
pliance before shutting off electrical supply.
WARNING
Do not use this furnace if any part has been
underwater. Immediately call a qualified service
technician to inspect the furnace and to replace
any part of the control system and any gas conĆ
trol which has been under water.
CAUTION
Before attempting to perform any service or
maintenance, turn the electrical power to unit
OFF at disconnect switch.
Page 2
Page 3
IMPORTANT
Any additions, changes, or conversions reĆ
quired in order for the appliance to satisfactorily
meet the application needs must be made by a
Lennox service technician using factory speciĆ
fied and approved parts.
3 - Turn off all electrical power to appliance.
4 - This appliance Is equipped with an ignition device
which automatically lights the burner. Do not try to
light the burner by hand.
5 - Remove control access panel.
6 - On Honeywell VR8205 gas valve, turn knob on gas
valve clockwise
to OFF. See figure 2.
IMPORTANT DIRECTIONS
1 - Keep the furnace area clear and free of combustible
material, gasoline, and other flammable vapors and liqĆ
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 furĆ
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.
LIGHTING INFORMATION AND OPERATION
WARNING
If you do not follow these instructions exactly, a
fire or explosion may result causing property
damage, personal injury or loss of life.
BEFORE LIGHTING 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.
Use only your hand to push in or turn the gas control knob.
Never use tools. If the knob will not push in or turn by hand,
do not try to repair it, call a qualified service technician. Force
or attempted repair may result in a fire or explosion.
To place 80MGF furnace into operation:
80MGF units are equipped with an electronic ignition sysĆ
tem. Do not
naces. Each time thermostat calls for heat, the burner will
automatically light.
Gas Valve Operation (Figure 2)
1 - STOP! Read the safety information at the beginning
2 - Set thermostat to lowest setting. See figure 1.
attempt to manually light burners on these furĆ
of this section.
THERMOSTATS
FIGURE 1
HONEYWELL VR8205 SERIES GAS VALVE
ON
OFF
GAS VALVE SHOWN IN OFF POSITION
FIGURE 2
7 - Wait fifteen (15) 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.
8 - On Honeywell VR8205 gas valves, turn knob on gas
valve counterclockwise to ON.
9 - Replace control 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 pilot line.
12- If the appliance still will not operate, follow the
instructions To Turn Off Gas To Unit" and call your
service 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 control access panel.
4 - On Honeywell VR8205 gas valves, turn knob on gas
valve clockwise
5 - Replace control access panel.
to OFF.
Page 3
Page 4
FILTERS
80MGF series units are equipped with external filters
which should be inspected monthly and replaced when
necessary to assure proper furnace operation. See table
1 for filter sizes. Replacement filters used with
80MGF-40/60/75 units must have a minimum velocity ratĆ
ing of 400 FPM. Replacement filters used with
80MGF-100/120/140 units require a minimum velocity
rating of 625 FPM. Figures 3, 4 and 5 show possible filter
locations.
TABLE 1
MODEL NO.
80MGF-45/60/75 16" X 20" X 1"
80MGF-100/120/140 20" X 20" X 1" 16" X 20" X 1"
UPFLOW FURNACE
BOTTOM RETURN AIR
FILTER SIZE
UPFLOW DOWNFLOW
1 FILTER 2 FILTERS
16" X 20" X 1"
DOWNFLOW FURNACE
FILTERS IN PLENUM RACK
FIGURE 5
BLOWER
Check and clean blower wheel for any debris. Blower moĆ
tor is prelubricated for extended bearing life. No further luĆ
brication is needed.
FIGURE 3
UPFLOW FURNACE
SIDE RETURN AIR
WARNING
Blower door must be securely in place when
blower and burners are operating. Gas fumes,
which could contain carbon monoxide, can be
drawn into living space resulting in personal inĆ
jury or death.
BURNER FLAME
The 80MGF burner flame is not adjustable; however, the
flame should be inspected at the beginning of each heatĆ
ing season and burners should be cleaned, if necessary.
Burner flame should be blue when burning natural gas,
blue/yellow when burning propane gas.
BURNER FLAME
FLAME APPEARS BLUE IF
BURNING NAT. GAS; BLUE/
YELLOW FOR PROPANE.
BURNER
FLAME
EXCHANGER
VEST
PANEL
HEAT
TUBE
FIGURE 4
FIGURE 6
Page 4
Page 5
VENTING SYSTEM INSPECTION
Annually (before heating season) inspect furnace venting
system, vent cap, heat exchanger and burners for corroĆ
sion, deterioration, or deposits of debris. Remove any obĆ
structions.
Contact your Lennox dealer for a periodic unit inspection
by a qualified service technician.
FLAME ROLLOUT SAFETY SWITCHES
Your Lennox furnace is equipped with two flame roll-out
safety switches which shut off the gas supply to the furĆ
nace in case of heat exchanger blockage. If the furnace
fails to operate due to the functioning of these safety
switches, DO NOT attempt to place the furnace into opĆ
eration. Contact 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 - Is gas turned on at meter?
7 - Is manual main shut-off valve open?
To keep your Lennox gas heating system in peak operatĆ
ing condition year after year, contact your independent
Lennox dealer about a planned service program.
Page 5
Loading...