Lennox 80UHG Series Guide

Page 1
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
80UHG
SERIES
GAS FURNACE
503,753M
7/99
Supersedes 9/98
Litho USA

PRODUCT LITERATURE
1999 Lennox Industries Inc.
Dallas, Texas

Page 2
80UHG PARTS IDENTIFICATION
2
3
1 - COMBUSTION AIR
BLOWER
2 - PRESSURE SWITCH
3 - BURNERS
4 - HEAT EXCHANGER
5 - GAS VALVE
6 - CONTROL BOARD
7 - BLOWER
7
1
5
6
4
WARNING
Pro uct contains fiberglass wool.Disturbing the
insulation in this pro uct uring installation,
maintenance, or repair will expose you to fiberĆ
glass wool. Breathing this may cause lung canĆ
cer. (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 further
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 appliance
before shutting off electrical supply.
WARNING
Do not use this furnace if any part has been un erĆ
water. Imme iately call a qualifie service techniĆ
cian to inspect the furnace an to replace any part
of the control system an any gas control which
has been un er water.
CAUTION
Before attempting to perform any service or mainteĆ
nance, turn the electrical power to unit OFF at isconĆ
nect switch.
IMPORTANT
Any a itions, changes, or conversions require in
or er for the appliance to satisfactorily meet the apĆ
plication nee s must be ma e by a Lennox service
technician using factory specifie an approve
parts.

Page 3
Important Directions
1 - Keep the furnace area c ear and free of combustib e
materia , gaso ine, and other f ammab e vapors and iqĆ
uids. If insta ed in an insu ated area, furnace must be
kept free of insu ating materia . Insu ating materia may
be combustib e. Inspect furnace venting system to
make sure it is in p ace, physica y sound, and without
ho es, corrosion, or b ockage. Inspect furnace return
air duct connection to ensure duct is sea ed to the furĆ
nace and terminates outside the space containing the
furnace. Inspect the physica support of the furnace to
guarantee that it is sound without sagging, cracks or
gaps around base and it maintains sea between base
and support.
2 - DO NOT obstruct air f ow to unit. Unit must receive an
unobstructed f ow of combustion and venti ating air.
3 - DO NOT store ch orine or f uorine products near unit or
introduce these products into the combustion air.
These products can cause furnace corrosion.
4- DO NOT raw return air from a room where this
furnace, or any other gas appliance (ie., a water
heater), is installe . When return air is drawn from a
room, a negative pressure is created in the room. If a
gas app iance is operating in a room with negative
pressure, the f ue products can be pu ed back down
the vent pipe and into the room. This reverse f ow of
the f ue gas may resu t in incomp ete 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 critica that the gas
supp ied to the unit be comp ete y burned to avoid the proĆ
duction of carbon monoxide gas. Comp ete combustion
of the gas requires, but is not imited to, correct gas presĆ
sure and gas f ow rate, adequate combustion air, and
proper venting.
WARNING
Carbon monoxi e gas is invisible, o orless, an
toxic.
Exposure to this gas can cause persona injury and
even death to a occupants, inc uding pets. Any item
that is powered by or gives off heat from a combustion
process (inc uding awn mowers, automobi es, and fireĆ
p aces) has the potentia to produce carbon monoxide
gas. Because of this, Lennox recommen s the use of
a carbon monoxi e etector in your home, even if
you o not own gas appliances. Re iab e detectors
are avai ab e at reasonab e retai prices. Contact your
independent Lennox dea er for more detai s about this
investment in your safety.
Your furnace is designed to meet standards set by nationĆ
a agencies, and to operate safe y when proper y insta ed
and maintained. However, the unit's performance can be
great y impacted by the individua insta ation and the opĆ
erating environment. It is your responsibi ity to ensure
that this app iance is maintained. Proper maintenance is
critica for your safety and the satisfactory operation of the
product. Lennox strongly recommen s annual inĆ
spection an maintenance of this appliance. Contact
your independent Lennox dea er for an inspection by a
qua ified service technician.
Lighting Information an 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 LI HTIN 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 80UHG furnace into operation:
80UH units are equipped with an electronic ignition
system. Do not attempt to manually light burners on
these furnaces. Each time thermostat calls for heat, the
burner will automatically light.
Gas Valve Operation (Figure 2 an 3)
1 - STOP! Read the safety information at the beginning
of this section.
2 - Set thermostat to owest setting. See figure 1.
THERMOSTATS
FIGURE 1
3 - Turn off a e ectrica power to app iance.
4 - This app iance Is equipped with an ignition device
which automatica y ights the burner. Do not try to
ight the burner by hand.
5 - Remove the contro access pane .

Page 4
6 - White Rodgers 36E Gas Valve - Switch gas va ve ever
to OFF. See figure 2.
Honeywell VR8205 Gas Valve - Turn knob on gas va ve
c ockwise to OFF. Do not force. See figure 3.
WHITE RODGERS 36E SERIES GAS VALVE
GAS VALVE SHOWN IN OFF POSITION
FIGURE 2
ON
OFF
HONEYWELL VR8205 SERIES GAS VALVE
GAS VALVE SHOWN IN OFF POSITION
FIGURE 3
7 - Wait five (5) minutes to c ear out any gas. If you then
sme gas, STOP! Immediate y ca your gas supp ier
from a neighbor's phone. Fo ow the gas supp ier's
instructions. If you do not sme gas go to next step.
8 - White Rodgers 36E Gas Valve - Switch gas va ve ever
to ON.
Honeywell VR8205 Gas Valve - Turn knob on gas
va ve counterc ockwise to ON. Do not force.
9 - Rep ace the contro access pane .
10 - Turn on a e ectrica power to unit.
11 - Set 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 app iance sti wi not operate, fo ow the
instructions To Turn Off Gas To Unit" and ca your
service technician or gas supp ier.
To Turn Off Gas To Unit
1 - Set thermostat to owest setting.
2 - Turn off a e ectrica power to unit if service is to be
performed.
3 - Remove the contro access pane .
4 - Switch ever on White Rodgers gas va ve to OFF; turn
knob on Honeywe va ve c ockwise to OFF. Do not
force.
5 - Rep ace the contro access pane .
Filters
80UH 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 80UH -40/60/75 units must have a minimum veĆ
locity rating of 400 FPM. Replacement filters used
with 80UH -100/120 units require a minimum velocĆ
ity rating of 625 FPM. Figures 4 and 5 show possible
filter locations.
TABLE 1
MODEL NUMBER
FILTER SIZE
MODEL NUMBER 1 FILTER
80UHG-45/60/75 16 in. X 20 in. X 1 in.
80UHG-100/120/140 20 in. X 20 in. X 1 in.
UPFLOW FURNACE
BOTTOM RETURN AIR
FIGURE 4

Page 5
UPFLOW FURNACE
SIDE RETURN AIR
FIGURE 5
Blower
Check and clean blower wheel for any debris. Blower
motor is prelubricated for extended bearing life. No
further lubrication is needed.
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 injury or eath.
Burner Flame
The 80UH burner flame is not adjustable; however,
the flame should be inspected at the beginning of each
heating season and burners should be cleaned, if necĆ
essary. Burner flame should be blue when burning
natural gas, blue/yellow when burning propane gas.
BURNER FLAME
BURNER
FLAME
HEAT
EXCHANGER
TUBE
VEST
PANEL
FLAME APPEARS BLUE IF
BURNING NAT. GAS; BLUE/
YELLOW FOR PROPANE.
FIGURE 6
Venting System Inspection
Annually (before heating season) inspect furnace
venting system, vent cap, heat exchanger and burnĆ
ers for corrosion, deterioration, or deposits of debris.
Remove any obstructions.
Contact your Lennox dealer for a periodic unit inspecĆ
tion 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 furnace 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 operation. Contact a qualified service technician.
Service Remin er
Call your Lennox service technician if unit is inoperaĆ
tive. Before calling, always check the following to be
sure service is required.
1 - Check that e ectrica disconnect switches are ON.
2 - Are access pane s secure y in p ace?
3 - Check room thermostat for proper setting.
4 - Rep ace any b own fuses or reset circuit breakers.
5 - Gas va ve shou d be ON.
6 - Air fi ter shou d not be p ugged imiting air f ow.
7 - Is gas turned on at meter?
8 - Is manua main shutĆoff va ve 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 6
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.
SIf you repeated y hear any new or unfami iar sounds
whi e your unit is operating, there may be a prob em.
For examp e, poor y performing burners can produce
unfami iar noises.
SIf you sme any unusua odors, your unit may be operĆ
ating improper y. For examp e, units can give off unfaĆ
mi iar odors if components are required to operate in
abnorma conditions.
SLook for visib e signs of a ma functioning unit. ExamĆ
p es inc ude unusua amounts of condensate on winĆ
dows inside your house, visib y burnt components or
unusua dirt or rust accumu ations on the vent pipe or
in the unit.
SIf you experience headache, nausea, fatigue, or dizziĆ
ness, the cause cou d be exposure to carbon monoxĆ
ide gas. This is often misdiagnosed as the f u because
symptoms are simi ar. If you suffer from f u- ike sympĆ
toms that are exaggerated at home, but seem to subĆ
side whi e you are away from the house, exposure to
carbon monoxide cou d be the cause.
Your vigi ance may pay off in ear y detection of a prob em
before either persona injury or property damage occurs.
Do not hesitate to contact a qua ified service technician as
an investment in your we being.
Planne Service
You shou d expect a service technician to check the fo Ć
owing items during an annua 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 insta ed) - 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 signs of water, damĆ
aged or sagging pipe, or disconnected joints.
Unit appearance - Must be inspected for rust, dirt, signs
of water, burnt or damaged wires, or components.
Fan access oor - Must be proper y in p ace and provide
a sea between the return air and the room where the furĆ
nace is insta ed.
Return air uct - Must be proper y attached and provide
an air sea to unit.
Operating performance - Unit must be observed during
operation to monitor proper performance of the unit and
the vent system.
Combustion gases - F ue products must be ana yzed
and compared to the unit specifications.
Prob ems detected during the inspection may make it
necessary to temporari y shut down the furnace unti the
items can be repaired or rep aced.
Pay attention to your furnace. Situations can arise beĆ
tween annua furnace inspections that may resu t in unĆ
safe operation. For instance, items innocent y stored next
to the furnace may obstruct the combustion air supp y.
This cou d cause incomp ete combustion and the producĆ
tion of carbon monoxide gas.