Lennox 80MGF-45 Guide

Page 1

PRODUCT LITERATURE
1993 Lennox Industries Inc.
Dallas, Texas
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, serĆ
vice agency or the gas supplier.
Do not try to light any appliance.
Do not touch any electrical switch; o not
use any phone in your buil ing.
Imme iately 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 epartment.
Extinguish any open flames.
RETAIN THESE INSTRUCTIONS
FOR FUTURE REFERENCE Litho U.S.A.
80MGF
SERIES
GAS FURNACE
503,069M
11/93
Superse es 502,893M

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80MGF PARTS IDENTIFICATION
UPFLOW POSITION DOWNFLOW POSITION
1
2
3
4
5
6
7
1
2
3
4
5
6
7
1 - COMBUSTION AIR
BLOWER
2 - PRESSURE SWITCH
3 - GAS VALVE
4 - ROLLOUT SWITCH
(One on each si e)
5 - BURNERS
6 - CONTROL BOARD
7 - BLOWER
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
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
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.

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IMPORTANT
Any a itions, changes, or conversions reĆ
quire in or er for the appliance to satisfactorily
meet the application nee s must be ma e by a
Lennox service technician using factory speciĆ
fie an approve parts.
IMPORTANT DIRECTIONS
1 - Keep the furnace area clear an free of combustible
material, gasoline, an other flammable vapors an liqĆ
ui s. If installe in an insulate 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 soun , an without
holes, corrosion, or blockage. Inspect furnace return
air uct connection to ensure uct is seale to the furĆ
nace an terminates outsi e the space containing the
furnace. Inspect the physical support of the furnace to
guarantee that it is soun without sagging, cracks or
gaps aroun base an it maintains seal between base
an support.
2 - DO NOT obstruct air flow to unit. Unit must receive an
unobstructe flow of combustion an ventilating air.
3 - DO NOT store chlorine or fluorine pro ucts near unit or
intro uce these pro ucts into the combustion air.
These pro ucts can cause furnace corrosion.
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 LIGHTING smell all aroun the appliance area
for gas. Be sure to smell next to the floor because some
gas is heavier than air an will settle on the floor.
Use only your han to push in or turn the gas control knob.
Never use tools. If the knob will not push in or turn by han ,
o not try to repair it, call a qualifie service technician. Force
or attempte repair may result in a fire or explosion.
To place 80MGF furnace into operation:
80MGF units are equippe with an electronic ignition sysĆ
tem. Do not attempt to manually light burners on these furĆ
naces. Each time thermostat calls for heat, the burner will
automatically light.
Gas Valve Operation (Figure 2)
1 - STOP! Rea the safety information at the beginning
of this section.
2 - Set thermostat to lowest setting. See figure 1.
3 - Turn off all electrical power to appliance.
4 - This appliance Is equippe with an ignition evice
which automatically lights the burner. Do not try to
light the burner by han .
5 - Remove control access panel.
6 - On Honeywell VR8205 gas valve, turn knob on gas
valve clockwise to OFF. See figure 2.
THERMOSTATS
FIGURE 1
ON
OFF
FIGURE 2
HONEYWELL VR8205 SERIES GAS VALVE
GAS VALVE SHOWN IN OFF POSITION
7 - Wait fifteen (15) minutes to clear out any gas. If you then
smell gas, STOP! Imme iately call your gas supplier
from a neighbor's phone. Follow the gas supplier's
instructions. If you o 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 esire 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" an 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
performe .
3 - Remove control access panel.
4 - On Honeywell VR8205 gas valves, turn knob on gas
valve clockwise to OFF.
5 - Replace control access panel.

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FILTERS
80MGF series units are equippe with external filters
which shoul be inspecte monthly an replace when
necessary to assure proper furnace operation. See table
1 for filter sizes. Replacement filters use with
80MGF-40/60/75 units must have a minimum velocity ratĆ
ing of 400 FPM. Replacement filters use with
80MGF-100/120/140 units require a minimum velocity
rating of 625 FPM. Figures 3, 4 an 5 show possible filter
locations.
TABLE 1
MODEL NO. FILTER SIZE
80MGF-45/60/75 16" X 20" X 1"
UPFLOW DOWNFLOW
16" X 20" X 1"
1 FILTER 2 FILTERS
80MGF-100/120/140 20" X 20" X 1" 16" X 20" X 1"
UPFLOW FURNACE
BOTTOM RETURN AIR
FIGURE 3
UPFLOW FURNACE
SIDE RETURN AIR
FIGURE 4
DOWNFLOW FURNACE
FILTERS IN PLENUM RACK
FIGURE 5
BLOWER
Check an clean blower wheel for any ebris. Blower moĆ
tor is prelubricate for exten e bearing life. No further luĆ
brication is nee e .
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 inĆ
jury or eath.
BURNER FLAME
The 80MGF burner flame is not a justable; however, the
flame shoul be inspecte at the beginning of each heatĆ
ing season an burners shoul be cleane , if necessary.
Burner flame shoul be blue when burning natural gas,
blue/yellow when burning propane gas.
BURNER FLAME
FIGURE 6
BURNER
FLAME
HEAT
EXCHANGER
TUBE
VEST
PANEL
FLAME APPEARS BLUE IF
BURNING NAT. GAS; BLUE/
YELLOW FOR PROPANE.

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VENTING SYSTEM INSPECTION
Annually (before heating season) inspect furnace venting
system, vent cap, heat exchanger an burners for corroĆ
sion, eterioration, or eposits of ebris. Remove any obĆ
structions.
Contact your Lennox ealer for a perio ic unit inspection
by a qualifie service technician.
FLAME ROLLOUT SAFETY SWITCHES
Your Lennox furnace is equippe 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 ue to the functioning of these safety
switches, DO NOT attempt to place the furnace into opĆ
eration. Contact a qualifie 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 require .
1 - Check that electrical isconnect switches are ON.
2 - Check room thermostat for proper setting.
3 - Replace any blown fuses or reset circuit breakers.
4 - Gas valve shoul be ON.
5 - Air filter shoul not be plugge limiting air flow.
6 - Is gas turne on at meter?
7 - Is manual main shut-off valve open?
To keep your Lennox gas heating system in peak operatĆ
ing con ition year after year, contact your in epen ent
Lennox ealer about a planne service program.