Lennox G24M SERIES User manual

¢:_2000 Lennox Industries Inc.
Dallas, Texas
INSTALLATION
INSTRUCTIONS
G24M Series
GAS FURNACE Technicld
504,1g7MSureLight_Ignition System _.L_PuF[T_')-bli_ations
02/2000
Supersedes 503.981M LithoUSA
RETAIN THESE INSTRUCTIONS
FOR FUTURE REFERENCE
i:-i:, i I
:::::::::::::_::::_:_::::::_:_:::_ _: : , ,, ........ r-
G24M Unit Dimensions ...................... 2
G24M Parts Arrangement .................... 3
G24M Gas Furnace ......................... 3
Shipping and Packing List .................... 3
Requirements .............................. 3
General ................................... 4
Combustion, Dilution& Ventilation Air .......... 5
Setting Equipment .......................... 8
Duct System .............................. 11
Venting ................................... 12
Gas Piping ................................ 19
Electrical ................................. 21
Unit Start-up .............................. 24
Gas Pressure Adjustment ................... 25
High Altitude Information .................... 25
Other Unit Adjustments ..................... 25
Service ................................... 27
Repair Parts List ........................... 28
Ignition Control Board Diagnostic Codes ...... 28
Troubleshooting ........................... 29
G24M Start-up & Performance Check Ust ..... 32
Do not store or use gasoline or oth-
er flammable vapors and liquids In
the vicinity of this or any other ap-
pliance.
Installation and service must be
performed by a qualified installer,
service agency or the gas supplier.
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 suppli-
er's instructions.
•If you cannot reach your gas supplier, call
the fire department.
Page 1

GAS PIPING 2 (51) ELECTRICAL INLETS
INLET
FLUE
OUTLET "
1
1
*NOTE - The supply air opening is _ with a 3/4 inch (19 n
scoredflange thatmay
sionsshown were taken after the flange was bent,
The double scoredflange at the front of the supply air open-
ing may be bent for a total opening dimension (front to rear)
of either 19-1/2 incheS(495 ram) or 19 inches (483 ram),
,4_ A -_----Ib
AIRtFLOW
(25
L
,ql'-**C_ _ 1
Opening- I (25)
FRONT VIEW
FLeft Side
ELECTRICAL
iNLETS
(Ei_erSide)
1
(25)
TOP VIEW
29-5/8
(752)
.3/4(19) II
19-1/2 ReturnAir_l L__ 1
(495) Opening Vl r" (25)
SIDE VIEW
Model No. A B C D E F G
G24M2-45 m. 17 36-1/4 15 6-3/4 2-7/16 1%1/2 6-1/2
G24M2-60
G24M3_60
G24M3-75 rnm 432 921 381 171 62 293 165
G24M4.75
G24M3/4-100 m, 20-1/2 39 18-1/2 8-3/8 4-1/4 13 8
G24M3/4.120
G24M4/5-100
G24M4/5-120 mm 521 991 470 213 108 931 203
m, 23-1/4 39 21-1/4 9-3/4 4-1/4 12-31/32 7-3/32
G24M4fS-140 mm 591 991 540 248 108 329 180
Page 2

G24M VENT ADAPTER _CABINET TOP I_
PARTS IDENTIFICATION HEATEXCHANGER
ASSEMBLY
FLUE BOX
COMBUSTION AIR
BLOWER _I
FRONT LOUVERED
PANEL
BURNER
AS_
CONTROL
BOARD
PRESSURE
PRIMARY
LIMIT _
LOW PRESSURE SWITCH
• Only)
TRANSFORMER
DOOR INTERLOCK SWITCH
NOx
TURBULATOR
SECONDARY
LIMITS
BLOWER ASSEMBLY
G24M
CABINET
CABINET
BOTTOM
The G24M gas furnace isshipped ready for installation
in the upflow position. The unit can easily be converted
for installation in either downflow or horizontal ap-
plications. The furnace is shipped with a bottom seal
panel in place for side return air in upflow applications.
Package I of 1 contains:
1-Assembled G24M unit(includes vent adapter except
for 140 kBtuhunits)
1 - Vent adapter(140 kBtuhunitsonly)
The following additiona/items may be orderedseparately,
ff required:
1 - Thermostat
1 - Externalfilterrack kit
1-Hanging bracket kit
1 - Propane/LP changeover kit
Check equipment for shipping damage. If you find any
damage, immediately contact the last carder.
LennoxG24M unitsare Amedcan Gas Association (AGA)
and Canadian Gas Association (CGA) cedified.
Inthe USA, installationof Lennox gas centralfurnaces must
conform with localbuilding codes. In the absence of local
codes, units must be installed according to the current Na-
tional Fuel Gas Code (ANSI-Z223.1) in the United States.
The NationalFuelGas Code is availablef/om the following
address:
Amedcan NationalStandardsInstitute,Inc.
11 West42nd Street
NewYork, NY 10036
In Canada, installationmustconformwithcurrentNational
Standardof Canada CAN/CGA-B149.1 "Installation Code
for Natural Gas BurningAppliances and Equipment"and
CAN/CGA-B149.2 "Installation Cede for Propane Gas
BurningAppliances and Equipment," local plumbingor
waste water Codesand otherapplicablelocal codes.
Page 3

Adequate clearance must be made around the air open-
ings into the vestibule area. Provisions must be made for
proper operation and for combustion air and ventilation air
supply according to the current National Fuel Gas Code or
CAN/CGA-B149 standards.
Vent installations must be according to the provided vent-
ing tables and applicable provisions of local building codes.
This furnace is AGA and CGA certified for installationclear-
ances tocombustible matedal as listedon the unitratingplate
and in the tables in figures 5, 7 and 9. Accessibility and ser-
vice clearances must take precedence over fire protection
clearances.
NOTE -For installation on combustible floors, the fumaca shall
not be installed directly on carpeting, b'le,or other combustible
material other than wood flooring.
For installation in a residential garage, the fumace must be
installed so that the bumer(s) and the ignitionsourceare lo-
cated no tessthan 18 inches (457 mm) above the floor.The
furnace must be located or protectedto avcid physicaldarn-
age byvehicles.Whena furnaceisinstalledina publicgarage,
hangar, or other building that has a hazardous atmosphere,
the furnace must be installed according to recomrnended
good practice requirements and current National Fuel Gas
Code or CAN/CGA B149.1 and B149.2standards.
The furnace must be adjusted to obtain a temperature dse
within the range specified on the unit rating plate.
The G24M fumace must be installed sothat electrical com-
ponents are protected from water.
When the furnace is used with cooling units, it shall be
installed in parallel with, or on the upstream sideof, cooling
units to avoid condensation in the heating compartment.
With a parallel flowarrangement, a damper (or othermeans
to control the flow of air) must adequately prevent chilled air
from entedng the furnace. If the damper is manually oper-
ated, it must be equipped to prevent operation of either the
heating or the cooling unit, unless itis in the full "HEAT" or
"COOL" setting.
When installed,the furnace must be electricallygrounded
accordingto localcodes.In addition,inthe United States,
installationmustconformwith the currentNationalElectric
Code, ANSI/NFPA No. 70. The National Electric Code
(ANSI/NFPA No. 70) is available from the followingad-
dress:
National Fire Protection Association
1 Battery March Park
Quincy, MA 02269
In Canada, all electrical wiring and grounding for the unit
must be installed according tothe current regulations of the
Canadian Electrical Code Part I (CSA Standard C22.1)
and/orlocal cedes.
Field wiring connections must meet or exceed specifica-
tions of type T wireand withstand a maximum temperature
rise of 180°F (82°C).
When the furnace isinstalled so that supply ducts carry air
circulated by the fumaceto areasoutside of the space con-
taining the furnace, retum air shall be handled by a duct(s)
sealed to the furnace casing and terminating outside space
containing furnace.
NOTE -G24M series unitsmust not be usedas a construc-
tion heater during anyphase of construction. Very low re-
turn air temperatures, harmful vapors and misplacement of
the fi#ers will damage the unit and lower its efficiency.
The Lennox G24M furnace may be installed in alcoves,
closets, attics, basements, garages and utility rooms in the
upflow, downflow, or hedzontal position.
This furnace design hasnot been AGA or CGA certified for
installation in mobile homes, recreational vehicles, or out-
doors.
AWARNING
These instructionsareintendedas a generalguideand de not
supersedelocalcodesinanyway.Consult authoritieshaving
judsd_ before installation.
In additionto therequirementsoutlinedpreviously,the fol-
lowinggeneral recommendationsshould be considered
when installingtheLennoxG24M furnace.
The furnaceshouldbeplacedas closetothe centerof the
air distributionsystemas possible.Thefurnaceshouldalso
be located closetothe chimneyorvent terminationpoint.
Do not installthefumaca where drafts mightblowdirectly
intoit. Thiscouldcause impropercombustionand unsafe
operation.
Do notblockfumaca combustionair openingswith cloth-
ing, boxes, doors,etc. Combustion airisneeded for proper
combustion and safe unit operation.
When the furnace is installed in an attic or other insulated
space, keep insulation away from the furnace.
Page 4

ZkWARNING I AWARNING
Inthepast,therewas noproblemin bringinginsufticientout-
door airtorcembustien.Infiltrationprovidedalllie airthatwas
needed.Intoday'shomes,_ght_n p_ctJcesmakeit
necessary tobdnginairfrom outsideforcombustion.Takeinto
accountthat exhaustfans, appliancevents, chimneys,and
fireplaces forceadditionalairthatcouldbeusedfor oombus-
tion outof the house.Unlessoutsideair is brm,'ghtintothe
houseforcombustion,negative pressure(outsidepressureis
greaterthaninsidepressure)willbuildtothepointthata down-
draft canoccurin_e fumacevent pipeorchimney.Asa result,
cembustiongasesenterhe living spacecreatinga potentially
dangeroussituation.
In theabsenceoflocalcodes concerning air forcombustion
and ventilation,use the guidelinesand proceduresin his
sectionto installG24M furnaces to ensureefficientandsafe
operation.You mustconsidercombustionair needsand re-
quirementsfor exhaustventsend gaspiping.A portionof this
informationhasbeenreprinted withpermission from theNa-
tionalFuelGas Code(ANSI-7_'_3.1).Thisreprintedmaterial
isnotthe completeandofficialpositionoftheANSIonthe ref-
erencedsubject,whichis representedonly bythestandardin
its entirety.
In Canada, refer to the standard CAN/CGA B149.1 and
B149.2 installationcodes.
,CAUTION
Allgas-firedappliancesrequire air forthe combustion pro-
cess. If sufficientcombustion air is not available,the fur-
nace or other appliance willoperate inefficientlyand un-
safely.Enoughair must beprovidedtomeettheneedsofall
fuel-burning appliances and apptiances such as exhaust
fans whichforce airout ofthe house. Whenfireplaces, ex-
haustfans, or clothesdryersare used at the same timeas
the furnace, much more air is required to ensure proper
combustionand to prevent adowndraft. Insufficientair
causesincompletecombustionwhichcan resultincarbon
monoxide.
Inadditionto providingcombustion air,freshoutdoorairdi-
lutes contaminants in the indoor air. These contaminants
may include bleaches, adhesives, detergents, solvents
and othercontaminantswhichcan corrodefurnacecompo-
nents.
The requirementsfor providingair for combustionand ven-
tilationdependlargely onwhether the furnace is installedin
an unconfinedor a confinedspace.
Unconfined Space
An unconfinedspace is an area such as a basement or
largeequipmentroomwith a volumegreaterthan50 cubic
feet (1.42 m3) per 1,000 Btu (.29 kW) perhourofthe com-
binedinput ratingof all appliances installedinthatspace.
This space also includes adjacent roomswhich are not
separated bya door.Thoughan area may appeartobe un-
confined,it mightbe necessary to bdngin outdoorair for
combustion ifthe structuredoesnot provide enoughair by
infiltration.If the furnace is located in a building of tight
constructionwith weather strippingand caulkingaround
the windows and doors, followthe procedures in the air
from outsidesection.
Page 5

ConfinedSpace
Aconfinedspaceisanarea witha volumelessthan50 cubic
feet (1.42 m3) par 1,000 Bto (.29 kW) par hourofthe com-
bined inputratingofall appliancesinstalled inthat space.This
definition includesfurnace closets or small equipment rooms.
When thefumace isinstalledsothat supplyducts carryair cir-
culated by the furnace to areasoutside the space containing
the fumace,the retumair must be handledby ductswhichare
sealedtothe fumaca casing and which terminate outs;dethe
space containing the furnace. This is especially important
whenthefurnaceismountedonaplatforminaconfinedspaoe
suchas a closetor smallequipmentroom.Evena smallleak
aroundthebaseof theunitat the platformorat thereturnair
ductconnectioncan cause a potentiallydangerousnegaUve
pressurecondition.Airfor combusiton and ventilationcanbe
brought intotheconfinedspace eitherfrominsidethebuilding
orfromoutside.
EQUIPMENT IN CONFINED SPACE
ALL AIR FROM INSIDE
CHIMNEY
G24M
FURNACE
i i I I II II Ii i i i i i i
NOTE-Each opening shall have a free area of at least one square
inch (645 mmz)per 1,000 Btu (.29 kW) per hour of the total inputrat-
ing of all equipment in the enclosure, but not teas then 1O0square
inches (64516 mrn2).
FIGURE 1
Air from Inside
If theconfinedspacethathouses thefurnace adjoinsa space
categorizedas unconfined,aircanbebroughtinbyproviding
two permanent openings between the two spaces. Each
opening must have a minimum free area of 1 square inch
(645 mm2) per 1,000Btu (.29kW) per hour of total input rat-
ing of all gas-fired equipment in the confined space. Each
opening must be at least 100 square inches (64516 ram2).
One opening shallbe within 12 inches(305 mm)of thetopof
the enclosureandone opening within 12 inches (305 ram) of
the bottom. See figure 1.
Air from Outside
If airfrom outsideis broughtinforcornbustionand ventilation,
the confinedspacemusthavetwo permanentopenings.One
opening shallbe within 12 inches (305 mm) ofthe top of the
enclosure and one openingwithin 12 inches (305 mm) ofthe
bottom. These openings must communicate directly or by
ducts with the outdoorsor spaces (crawl or attic) that freely
communicate withthe outdoors or indirectlythroughvertical
ducts. Each opening shall have a minimum free area of 1
square inch(645 mm2) par 4,000 Btu (1.17 kW) per hour of
totalinput ratingof allequipmentin the enclosure.See figures
2 and 3. Whencommunicatingwith theoutdoorsthroughhod-
zontal ducts, each opening shall have a minimum free area
of 1 square inch(645 mm2)par 2,000 Btu (.55 kW) par total
input ratingof all equipment in the enclosure.See figure 4.
When ducts are used, they shall be of the same cross-sec-
tionalarea asthefreearea oftheopeningstowhich they con-
nect. The minimum dimension of rectangular air ducts shall
be no less than 3 inches (75 mm). In calculating free area,
the blocking effect of louvers, gdlles, or screens must be
considered. Ifthedesign and free area ofprotective covering
is not known for calculatingthe size opening required,it may
be assumedthat woodlouvers willhave20 to 25 percentfree
area and metal louvers and grineswill have 60 to 75 percent
free area. Louvers and grillesmust be fixed in the open posi-
tionorinterlockedw_ theequipmentso thattheyare opened
automaticallydudngequipmentoperation.
Page 6

CH{MNEY OR
GAS VENT _1
EQUIPMENT IN CONFINED SPACE
ALL AIR FROM OUTSIDE
(Inlet Air from Crawlspace and Outlet Air to Ventilated
Attic)
G24M
FURNACE
VENTILATION LOUVERS
(EaCh end of atdc)
WATER
HEATER
VENTILATION
LOUVERS
(For uni_ealed craw!
rrrrn rrrmi
NOTE- The inletand outJefairnpemngs shafteach havea freearea of at leastone
square _ch {645 turn2) per 4,000 Btu (1.17 kW)per hour of thetotalinputrating of
a/! equipment in the enclosure.
FIGURE 2
EQUIPMENT IN CONFINED SPACE
ALL AIR FROM OUTSIDE
(All Air Through Ventilated Attic)
VENTILATIONLOUVERS
(Eachendof ate)
G24M
FURNACE
NOTE-The inletand outJetair openings8hall each havea
free area of at least one square inch (645 mm2)per 4,_0
Btu (1.17 kW}per hour of the total inputratingof all equip-
ment in the enstosure.
FIGURE 3
FIGURE 4
P_e7

ii i i ii ii ; il; = iiiiiiiiiiil
The Lennox G24M multi-position gas furnace can be
installed as shipped in upflow or horizontal position with
right-hand or left-hand discharge. The furnace can easi-
ly be converted for downflow applications.
Select a location that allows for required clearances
listed on the unit rating plate. Also consider gas supply
connections, electrical supply, vent connection and
installation and service clearances [24 inches (610 mm)
at unit front].
NOTE -1/3and 1/2hp blowermotors are equipped with ei-
ther four flexible mounting legs or three flexible legs and
one rigid leg. The dgid leg is equipped with a shipping bolt
and a flat white plastic washer (rather than the rubber
mounting grommet used witha flexible mounting leg). This
shipping bolt and flat washer must be removed before the
furnace is put into operation. Once the shippingbolt and
washer are removed, the rigid leg will not touch the fan
housing.
Upflow Applications
The LennoxG24M furnace is shipped in a standardupflow
position.Level_furnaceusingshimsor levelingbolts.Four
knockoutsinthefumaca b_sepanelarefactory-providedfor
the installationof levelingbolts (field-provided).Allow for
clearancestocombustiblematerialsas indicatedon theunit
ratingplate.Minimumclearancesfor closetoralcove installa-
tionsare shownin figure5.
In upfiowapplications, returnair can be broughtin through
the bottom or eitherside of the furnace. If a furnace with
bottomreturnair isinstalledona platform,make an airtight
sealbetween the bottomofthefurnaceand theplatformto
ensureproperand safe operation.
Knockouts areprovided on both sidesof thefurnace cabi-
net for installations with side return air.When side return air
is used, sealthe bottom ofthe furnace using the panel pro-
vided.
An upflow filter rack is available and must be ordered sepa-
rately. The adjustable rack can be installed beneath the fur-
nace (flush with cabinet edges) for bottom return air ap-
)lications or on theside of the furnace for side return air.
Upflow Application
Installation Clearances
LEFT
SIDE
TOP
BOTTOM
RIGHT
S;DE
1 in. t'25ram) 1In. (25 mm_ I
2in.(51mm) 2in.(51mm}]
0 0
0 o
6in.(152mm) 1in.(25mm}i
0" 0"
*Front clearance in alcove Installation must be 24 in. (610
ram). Maintain a minimum of 24 in. (610 rnm) for front service
eccess.
*" For installations on acombustible floor, do not install the
furnace directly on carpeting, tile or other combustible mate-
rials other than wood flooring=
Vent
Connector Type C Type BI
Twe
TOP
*FRONT
BACK
SIDES
VENT
FLOOR
FIGURE 5
REMOVE
TOPCAP
REMOVE
FOUR
SCREWS
REMOVE
BOTTOM
UNIT CONVERSION FOR DOWNFLOW APPLICATION
SINGLE-WALLED VENT ,,.._.,..,._._
PtPE FROM COMBUSTION
AIR BLOWER FLUE
ADAPTER TO FURNACE
FLUIE OUTLET
(FumW_ed by Imta_eq
RECONNECT
WIRE HARNESS JACK
PLUGS AND SENSOR
LEAD AT CONTROL
BOARD
DISCONNECT WIRE
HARNESS JACKPLUGS
AND SENSOR LEAD
FROM CONTROL
8OARD
UPFLOW CONFIGURATION
'II
I I o
PJEINSTALL
/Topc,,.-oN
UNIT BOTTOM
ROrATE HEATEXCHANGER &
REINSTALL
_-- REIN_rALL
BOTTOM ON
UNIT TOP
DOWNFLOWCONFIGURATION
FIGURE 6
Page 8

DownflowApplications
The LennoxG24M furnaceisshippedinthe upflowconfig-
uration and mustbe converted for downflowinstallation.
Refer tofigure6 and thefollowingstepstoconvertthe unit
for downflowinstallation:
1 - Place uniton itsbackand remove access panel.
2- Disconnect wire harness jackplugs from control
board.
3 - Disconnect sensor lead from control board.
4 - Remove four screws securing cabinet top cap to cabi-
net.
5 - Remove four screws holding heat exchanger assem-
bly in place. Slide heat exchanger out through top of
cabinet.
6 - Rotate heat exchanger 180° and slide back into cabi-
net throughtop. Resecure using four screws.
7 - Remove four screws securing cabinet bottom piece
to cabinet. Replace with cabinettop cap.
8 - Use four screws to install cabinet bottom piece where
cabinet top was.
9 - Reconnect sensor lead to control board.
10- Reconnectwire harness jackptugs to control board.
11- Replace unit access panel.
12- Use cord clip located on right side of furnace to
hold wiring away from hot surfaces in heating
compartment. Install two#10 sheet metal screwsin
cabinet top toprovide a better air seaL
Indownflowapplications,the unitcanbeinstalledinthree dif-
ferent ways: on non-combustibleflooring, on combustible
floor usinganadditivebase, oron areverse-flow coolingcab-
inet. Do not drag unit across floor.
Allow clearances to combustible materials as indicated on
unit rating plate. Minimum clearances for closet or alcove
installations are shown in figure 7.
DOWNFLOWINSTALLATIONCLEARANCES
TOP
(60 Hz. only)
LEFT RIGHT
SIDE SiDE
BOTTOM
VENT TYPE C TYPE Bt
CONNECTOR
TOP 1"I25mm_ 1*125mint
•FRONT 2"I51mm) 2" t81mm)
BACK 0 0
SIDES 0 0
VENT 6" {r 52rnm'p I" t25mrn_
FLeeR NC" NC"
NC - Non-combustible floor
"Front clearance In Ilcove Install_tion must be • nlln. of 24" (610rnm)
for front service IOCaKK.
"With addiUve base on combustible floor.
FIGURE 7
A separate downflow filter kit isavailable for use in down-
flow applications.
A*lnstallation on Non-Combustible Flooring
1 - Cut floor opening keeping in mind the clearances
listedonthe unitrating plate.Also, keep in mindgas
supply and electrical supply, vent connections and
sufficient installationand service clearances. See
table 1for correct flooropening size.
TABLE 1
NONCOMBUSTIBLE FLOOR OPENING
G24M*45/60/75
G24M-1001120
G24M-140
Front to Rear
UNIT In mm
19-3/4 502
19-3/4 502
19-3/4 502
Side to Side
In mm
15-1/4 388
18-3/4 477
21÷1/2 546
COTE-Flooropeningdimensionslistedare1/4"(6rnm) larger thanunit
openings.
2 - Flange warm air plenumand lower intoopening.
3 - Set unitover plenum.
4 - Check to see that anadequate sealis made.
B4nstallation on Combustible Flooring
1 - When unitisinstalledon a combustiblefloor,an addi-
tive base (ordered separately) must be installedbe-
tween the furnace and the floor. See table 2 for open-
ing size to cut in the floor.
TABLE 2
ADDITIVE BASE FLOOR OPENING
UNIT
G24M-45/60/75
G24M-100/120
G24M.140
Front to Rear
in rnm
21-7/8 556
21-718 556
21-718 556
Side to Side
in mm
17-5/t6 440
20-3/4 528
23-1/2 597
NO TE -Floor opening dimensionslistedare 1/4" (6ram) larger than addi-
tive base openings.
COMBUSTIBLE FLOORING INSTALLATION
G24M
ADDITIVE
BASE
SUPPLY AIR
_" PLENUM
1. Cut correct size floor _:
2. Set additive base intoopening._
3. Set supply air plenum into additive base.
4. Set unit,
FIGURE 8
SIZED FLOOR
OPENING
Page 9

2-After opening is cut, set the additive base into opening.
3 - Check fiberglass strips on additive base to make sure
they are propedy glued and positioned.
4 - Lower supply air plenum into additive base until ple-
num flanges seal against fiberglass strips.
5- Set unit on additive base so unit flanges drop into ple-
num. Refer to figure 8.
NOTE -Be careful not to damage fiberglass strips.
Check for tight seal
C-installation on Cooling Cabinet
1 - Refer to reverse-flow coil installationinstructions for
correctlysizedopeninginfloorand installationofcabi-
net.
2- When cooling cabinet is in place, installfurnace so
flangesdrop insidecabinetopening.
3-Seal cabinet and checkfor air leakage.
Horizontal Applications
The Lennox G24M furnace can be installedin horizontal
applications in either upflow or downflow configuration
(See figure6). It ispreferabletoinstalltheunitin thestan-
dard upflow configuration,if possible, because the vent
pipewillnot interferewithserviceaccess forblower.Install
two #10 screws in the cabinet bottom(upflow configura-
tion)or cabinet top (downflowconfiguration)to provide a
betterair sea].The unit cannot be installed on its back.
HorizontalApplication
installation Clearances
TOP
SIDE S_DE
BOTI'OM
Vem
Connector
Type
TOP
*FRONT
SACK
SIDES
VENT
FLOOR
Type C
0
2in. (51 ram)
0
2in. (51 rnm)
6 in. (152 ram)
0._
Type BI
o
2 in. 151 ram)
0
2 in. (51 ram)
1 in. (25 turn
0"*
*Front clearance in alcove installation must be 24 in.
(610 ram). Maintain aminimum of 24 in, (610 ram) for
front service access,
** For installations on a combustible floor, do not install
the furnace directly on carpeting, tile or other combus-
tible materials other than wood flcorlng.
FIGURE g
Allow for clearancesto combustiblematerials as indicated
on the unit ratingplate. Minimum clearancesfor closet or
alcove installationsare shown infigui'e9.
Furnacesmay be installed in either anatticor a crawispace.
See figure 10 for furnace installationson a platform.
NOTE -When the furnaceis installed on a platform in a
crawlspace, it must be elevated enough to avoid water
damage and to allow the air conditioning coil to drain.
Horizontal Application
Unit Installed on Platform
_IOTE-LinecontactispermissibleSeethe unitrating plateforclearances.
_VENTPIPE
WORKING
pLATFORM
FIGURE 10
Anyone ofthefollowingmethodsmay be usedtosuspendthe
furnace fiom roofraftersorfloorjoists:
1 - Using Lennoxhanging bracket kitcatalognum-
ber46366 -
Install as indicatedin the instaltationinstructions
providedwiththe hangingbracketkit.
2 - Using angle iron with at least 1/4 in. diameter
rods -
Install as shown in figure 11.
Note -Rods must not inter[erav_h plenum or ex-
haustpiping;coolingcoils and supplyand return
air plenums must be supported separately.
FIGURE 11
Page 10