LENNOX Furnace/Heater, Gas Manual L0406231

User Manual: LENNOX LENNOX Furnace/Heater, Gas Manual LENNOX Furnace/Heater, Gas Owner's Manual, LENNOX Furnace/Heater, Gas installation guides

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¢:_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

scored flange that may

sionsshown were taken after the flange was bent,

The double scored flange 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 is shipped 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 kBtuh units)

1 - Vent adapter (140 kBtuh unitsonly)

The following additiona/items may be ordered separately,

ff required:

1 - Thermostat

1 - Externalfilter rack 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.

In the USA, installation of Lennox gas centralfurnaces must

conform with local building 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 NationalFuel Gas Code is availablef/om the following

address:

Amedcan National StandardsInstitute, Inc.

11 West 42nd Street

NewYork, NY 10036

In Canada, installationmust conformwithcurrentNational

Standardof Canada CAN/CGA-B149.1 "Installation Code

for Natural Gas Burning Appliances and Equipment"and

CAN/CGA-B149.2 "Installation Cede for Propane Gas

Burning Appliances and Equipment," local plumbing or

waste water Codesand other applicablelocal 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 installation clear-

ances to combustible matedal as listedon the unit rating plate

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 ignition sourceare lo-

cated no tess than 18 inches (457 mm) above the floor.The

furnace must be located or protected to avcid physical darn-

age by vehicles.When a furnaceis installedina 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 B149.2 standards.

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 other means

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 it is in the full "HEAT" or

"COOL" setting.

When installed,the furnace must be electricallygrounded

accordingto local codes. In addition, in the United States,

installationmust conformwith 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 to the current regulations of the

Canadian Electrical Code Part I (CSA Standard C22.1)

and/or local cedes.

Field wiring connections must meet or exceed specifica-

tions of type T wire and withstand a maximum temperature

rise of 180°F (82°C).

When the furnace is installed so that supply ducts carry air

circulated by the fumace to areas outside 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 used as a construc-

tion heater during any phase 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 has not been AGA or CGA certified for

installation in mobile homes, recreational vehicles, or out-

doors.

AWARNING

These instructionsareintendedas a generalguideand de not

supersedelocalcodesinany way.Consult authoritieshaving

judsd_ before installation.

In additionto the requirementsoutlinedpreviously,the fol-

lowing general recommendationsshould be considered

when installingthe LennoxG24M furnace.

The furnaceshouldbe placed as closeto the centerof the

air distributionsystemas possible.Thefurnace shouldalso

be located closeto the chimneyorvent terminationpoint.

Do not installthe fumaca where drafts mightblow directly

intoit. This couldcause impropercombustionand unsafe

operation.

Do notblock fumaca combustionair openingswith cloth-

ing, boxes, doors,etc. Combustion airis needed 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

In the past,therewas noproblemin bringinginsufticientout-

door airtor cembustien. Infiltrationprovidedalllie airthatwas

needed.Intoday'shomes,_ght _n p_ctJcesmakeit

necessary tobdnginairfrom outsideforcombustion.Takeinto

accountthat exhaustfans, appliancevents, chimneys,and

fireplaces forceadditionalairthat couldbe usedfor oombus-

tion outof the house.Unless outsideair is brm,'ghtintothe

houseforcombustion,negative pressure(outsidepressureis

greaterthan insidepressure)willbuildtothe pointthata down-

draft canoccurin_e fumacevent pipeorchimney.As a result,

cembustiongasesenterhe living spacecreatinga potentially

dangeroussituation.

In the absenceof localcodes concerning air forcombustion

and ventilation,use the guidelines and proceduresin his

sectionto installG24M furnaces to ensureefficientandsafe

operation.You mustconsidercombustionair needsand re-

quirementsfor exhaustventsend gaspiping.A portionof this

informationhas beenreprinted withpermission from the Na-

tionalFuel Gas Code (ANSI-7_'_3.1).This reprinted material

is not the completeandofficialpositionof theANSI onthe ref-

erencedsubject,whichis representedonly bythe standardin

its entirety.

In Canada, refer to the standard CAN/CGA B149.1 and

B149.2 installationcodes.

,CAUTION

All gas-firedappliancesrequire air forthe combustion pro-

cess. If sufficientcombustion air is not available,the fur-

nace or other appliance will operate inefficientlyand un-

safely.Enoughair must be providedto meetthe needs of all

fuel-burning appliances and apptiances such as exhaust

fans whichforce airout of the house. When fireplaces, ex-

haustfans, or clothesdryersare used at the same timeas

the furnace, much more air is required to ensure proper

combustionand to prevent adowndraft. Insufficientair

causes incompletecombustionwhich can resultincarbon

monoxide.

Inadditionto providingcombustion air,freshoutdoorairdi-

lutes contaminants in the indoor air. These contaminants

may include bleaches, adhesives, detergents, solvents

and other contaminantswhichcan 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

large equipmentroomwith a volume greater than50 cubic

feet (1.42 m3) per 1,000 Btu (.29 kW) perhourof the com-

binedinput ratingof all appliances installedinthat space.

This space also includes adjacent rooms which are not

separated bya door.Thoughan area may appear to be un-

confined,it might be necessary to bdngin outdoorair for

combustion if the structuredoesnot provide enoughair by

infiltration.If the furnace is located in a building of tight

constructionwith weather stripping and caulkingaround

the windows and doors, followthe procedures in the air

from outsidesection.

Page 5

ConfinedSpace

Aconfinedspaceis an area witha volumelessthan50 cubic

feet (1.42 m3) par 1,000 Bto (.29 kW) par hourof the com-

bined input rating of all appliancesinstalled inthat space. This

definition includesfurnace closets or small equipment rooms.

When the fumace isinstalledso that supplyducts carryair cir-

culated by the furnace to areas outside the space containing

the fumace,the retumair must be handledby ducts whichare

sealedto the fumaca casing and which terminate outs;dethe

space containing the furnace. This is especially important

whenthefurnaceismountedonaplatforminaconfinedspaoe

suchas a closetor smallequipmentroom.Even a smallleak

aroundthe base of the unitat the platformorat the returnair

ductconnection can cause a potentiallydangerousnegaUve

pressurecondition. Airfor combusiton and ventilationcan be

brought intothe confinedspace eitherfrominsidethe building

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 the furnace adjoinsa space

categorized as unconfined,aircan be broughtinby providing

two permanent openings between the two spaces. Each

opening must have a minimum free area of 1 square inch

(645 mm2) per 1,000 Btu (.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 shall be within 12 inches(305 mm)of the topof

the enclosureandone opening within 12 inches (305 ram) of

the bottom. See figure 1.

Air from Outside

If airfrom outsideis brought infor cornbustionand ventilation,

the confinedspacemusthave two permanentopenings.One

opening shall be within 12 inches (305 mm) of the top of the

enclosure and one openingwithin 12 inches (305 mm) of the

bottom. These openings must communicate directly or by

ducts with the outdoorsor spaces (crawl or attic) that freely

communicate withthe outdoors or indirectly through vertical

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. When communicatingwith the outdoorsthrough hod-

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 rating of all equipment in the enclosure. See figure 4.

When ducts are used, they shall be of the same cross-sec-

tionalarea as the free area of the openings to which 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. Ifthe design and free area of protective covering

is not known for calculatingthe size opening required, it may

be assumed that wood louvers will have 20 to 25 percentfree

area and metal louvers and grineswill have 60 to 75 percent

free area. Louvers and grilles must be fixed in the open posi-

tion orinterlockedw_ the equipmentso 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 have a free area of at least one

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 openings 8hall each have a

free area of at least one square inch (645 mm2)per 4,_0

Btu (1.17 kW}per hour of the total input ratingof 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 -1/3 and 1/2 hp blower motors 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_furnaceusing shimsor levelingbolts. Four

knockoutsinthefumaca b_se panelare factory-providedfor

the installationof leveling bolts (field-provided).Allow for

clearancesto combustiblematerialsas indicatedon the unit

ratingplate.Minimumclearances for closetoralcove installa-

tionsare shownin figure5.

In upfiowapplications, returnair can be broughtin through

the bottom or either side of the furnace. If a furnace with

bottomreturnair is installedona platform,make an airtight

seal between the bottomof the furnace and the platformto

ensure properand safe operation.

Knockouts are provided on both sidesof the furnace cabi-

net for installations with side return air. When side return air

is used, seal the bottom of the 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 the side of the furnace for side return air.

Upflow Application

Installation Clearances

LEFT

SIDE

TOP

BOTTOM

RIGHT

S;DE

1 in. t'25 ram) 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 furnace is shippedinthe upflowconfig-

uration and must be converted for downflow installation.

Refer tofigure6 and the followingstepsto convertthe unit

for downflowinstallation:

1 - Place uniton its back and 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 cabinet top 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 screws in

cabinet top to provide a better air seaL

Indownflowapplications,the unitcan be installedinthree dif-

ferent ways: on non-combustibleflooring, on combustible

floor using an additivebase, oron areverse-flow cooling cab-

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 is available for use in down-

flow applications.

A*lnstallation on Non-Combustible Flooring

1 - Cut floor opening keeping in mind the clearances

listed onthe unit rating plate. Also, keep in mindgas

supply and electrical supply, vent connections and

sufficient installation and 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-Flooropeningdimensionslistedare 1/4"(6rnm) larger than unit

openings.

2 - Flange warm air plenumand lower into opening.

3 - Set unitover plenum.

4 - Check to see that an adequate seal is made.

B4nstallation on Combustible Flooring

1 - When unit is installedon 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 into opening._

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

correctlysized openinginfloorand installationof cabi-

net.

2- When cooling cabinet is in place, installfurnace so

flanges drop insidecabinet opening.

3-Seal cabinet and check for air leakage.

Horizontal Applications

The Lennox G24M furnace can be installed in horizontal

applications in either upflow or downflow configuration

(See figure6). It is preferable to installthe unit in the stan-

dard upflow configuration,if possible, because the vent

pipewill not interferewithserviceaccess forblower. Install

two #10 screws in the cabinet bottom (upflow configura-

tion) or cabinet top (downflow configuration)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 clearances for closet or

alcove installationsare shown infigui'e9.

Furnaces may be installed in either an atticor a crawispace.

See figure 10 for furnace installationson a platform.

NOTE -When the furnace is 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-Linecontactis permissibleSeethe unitrating plateforclearances.

_VENTPIPE

WORKING

pLATFORM

FIGURE 10

Anyone ofthefollowingmethodsmay be usedtosuspendthe

furnace fiom roofraftersorfloor joists:

1 - Using Lennoxhanging bracket kit catalog num-

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

IAWARNING

3- Using heavy gauge perforated steel straps

("plumber's straps') -

Install as shown in figure 12.

Note -Straps must not interfere withplenum or ex-

haust I_ping; cooling coils and supply and return

air plenums must be supported separately.

Horizontal Application

Unit Suspended in Attic or Crawlspace

Using Heavy Gauge Perforated Steel Straps

("Plumber's Straps")

Inches (ram)

Level unit - side to side and end to end.

PLUMBER'S Use existing blower deck screws to secure

Also use washers, if required,

2-13/16

1-1/2 (38)

SUPPLY

AIR

Atthe unit's top corners, secure each strap to the furnace, positJone_

as shown, using st least two sheetrnetal screws:

maximum screw length - 3/4 in. and minimum screw size - # 10.

1-1/2 {38)

TOP OF UNIT

/

RETURN AIR 112 1/2

OPENING (13) (13)

END VIEW

1-1/2 (3S)

1/2

(13) TOP OF UNIT

112 ;UPPLY AIR

(13) OPENING

END VIEW

FIGURE 12

Use industry-approvedstandards to size and installthe

supplyand rstumair ductsystem.This willresultina quiet

and low-staticsystemthat has uniformair distdbution.

Supply Air Plenum

Furnacesinstalledwithouta coolingcoilrequirethe instaUa-

tion of e removableaccesspanel inthe supplyairduct.The

accesspanelshouldbe largeenoughto permitinspection(ei-

ther by smoke or reflectedlight)of the heat exchangerfor

leaks after installation.The furnace access panel mustal-

waysbe in placewhen the furnace is operatingand it must

notallowleeksintothe supplyair ductsystem.

Return Air Plenum

Return air must not be drawn from a room where this

furnace, or any other gas appliance (ie., a water heat-

er), is installed. When return air is drawn from a room,

a negative pressure is created in the room. If a gas ap-

pliance is operating in a room with negative pressure, the

flue productscan be pulled back down the vent pipe and

into the room. This reverse flow of theflue 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.

In upfiowapplications,returnair can be brought in through

the bottomor either side of the furnace. If afurnace with

bottomreturnairis installedon a platform,makean airtight

seal between the bottomof the furnace and the platformto

ensure proper and safe operation. Use fiberglasssealing

stripsbetweenthe plenumand the furnace cabinet to en-

sure a tightseal.If a filter is installed,sizethe returnair duct

to fit the filterframe.

In downfiow applications,usethe followingsteps when instal-

ling rstum air plenum:

1-Flange bottom edge of plenum with a hemmed edge.

See figure 13.

2 - Use fiberglass sealing strips between plenum endthe

unit cabinet to ensure a tight seal.

Page 11

3- Inallcases,securetheplenumtothetop flanges of the

furnace using sheet metal screws.See figure 13.

PLENUM.._._ JSECURE

._ HEMMED EDGE

FIGURE 13

4 - In closet installations,it may be necessary to install

sheet metalscrews from the inside.Ifthis isthe case,

make plenumwitharemovablefront to installscrews

as shownin figure 14.

a _ PLENUM

SECURE FROM .jl_

,NSIDE_,_._ HEMMED EDGE

FIGURE t4

: ::_:i_:::_:::_::'::::iii%::_:.iiii::iiiiiiiiii'ii'::iiii ::ii_ii'ii_i::ii'i_=:i'==:i"i_i'i'i?i_i'iii_i;i_iii'i_i'i':.:iiiiii::%::i":::.i i:.i'

.V mg ...................................................................................................................................................................

Avent adapter is factory-installed on the combustion air

blower outlet of all models, except the G24M-140. On the

G24M-140, the flue adapter is supplied with the furnace,

and must be field-installed, between the combustion air

blower flueouUetand the vent connector, using one or two

corrosion-resistant screws. Modification of or failure to

install the adapter will cause unsafe unit operation and

will void AGA and CGA unit certification, The vent con-

nectordoes not require insulation.

The G24M sedes units are classified as fan-assisted Cate-

gory tfurnaces when vertically vented according to the btest

edition of ANSI Z21.47 Central Fumaca Standard in the

USA and the current standards of CAN/CGA B149.1 and

B149.2 of the Natural Gas and Propane Installation Code in

Canada. A fan-assisted Category I furnace is an appliance

equipped with an integral mechanical means to eitherdraw

or force productsof combustion through the combustion

chamber and/or heat exchanger.

NO TE -Use these instructions as eguide. They do not su-

persede local codes.

The vent sizingtables in this manual were extracted from

the National Fuel Gas Code (NFPA 54 /ANSI Z223.1 ) end

are provided as a guide for proper vent installation. Proper

application,termination, construction and location of vents

must conform to local codes having jurisdiction. In the ab-

sence of local codes,the NFGC servesas the definingdoc-

ument.

Referto the tablesand the ventinginformationcontained in

these instructionsto properlysize and installthe venting

system.

Installthe first ventconnectorelbowa'minimumof 6 inches

(152 ram) fromthe furnace vent outlet.

Venting Using a Masonry Chimney

The following additional requirements apply when a lined

masonry chimney is used to vent an G24M furnace.

Masonry chimneys used to vent Category I central fur-

naces must be either tile-lined or lined with e listed metal

lining system or dedicated gas vent. Unlined masonry

chimneys are prohibited. See figures 15 and 16 for com-

mon venting.

A Category I appliance must never be connected to achim-

ney that is servicing e solid-fuel appliance. If a fireplace

chimney flue is used to vent this appliance, the fireplace

opening must be permanently sealed.

A fan-assisted fumaca may be commonly vented into an

existing lined masonry chimney if the following conditions

are met:

1 - The chimney is currently serving at least one draft-

hood equipped appliance.

2 - The vent connectors end chimney are sized according

to the provided venting tables for the USA, and the ap-

propriate venting tables in the standards of CAN/CGA

B149.1 and B149.2 of the Natural Gas and Propane

Installation Code in Canada.

A type B1vent or mascnry chimney Itoershallterrninatsabove

the roofsurfacawithe listedcap or a listed roof assemblyac-

cordingto the terms of their respective listingsand the vent

manufacturer'sinstrucfions.

Do notinstalla manualdamper, barometric draft regulator,

or flue restdctor between the furnace and the chimney.

If type B1 double-wall vent is used insidee chimney, no oth-

er appliance can be vented into the chimney. Outer wall of

type B1 vent pipe must not be exposed to flue products.

Insulation for the flexible vent pipe must be an encapsu-

lated fiberglass sleeve recommended by the flexiblevent

pipe manufacturer. See figure 15.

The space between the liner and the chimney wail

should NOT be insulated with puffed mica or any other

loose granular insulating material.

If B1 vent or an insulated flexiblevent pipe cannot be used

as liners, the chimney must be rebuilt to accommodate one

of these methods or some alternate approved method

must be found to vent the appliance.

When inspection reveals that an existing chimney is not safe

for_e intended purpose, it shall be rebuilt to conform to na-

tionally recognized standards, linedor relined with suitable

materials or replaced with e gas vent or chimney suitablefor

venting G24M seriesunits. The chimney passageway must

be checked periodically to ensure that it is clear and free of

obstructions.

Page 12

Common Venting Using Metal-lined Masonry Chimney

MAX. LENGTH

- SEE NOTE 1

BELOW,

4in, (102rmm) _'_

OTHER

APPLIANCE

i 1i

EXTERLOR

CHIMNEY WITH

I!11 <s,

PERMANENTLY

SEALED FIREPLACE

OPENING

NOTE 1 o Refer to the provided venting tables for installations in the USA and the venting tables in CAN/CGA.B149.1 for insfalletlons Canada

NOTE 2- Either single*watied or double.walled vent connector may be used. Refer to the capacity e_luirementa shown in the

provided venting tables for installations in USA end the venting tables in current CAN/CGA-B1411.1for Installations in Canada,

FIGURE 15

NOTE- Refer to provided venting tables

for installations in the USA and the

venting tables in current CAN/CGA-

B14g I for installations in Canada.

Common Venting Using Tile-tined Interior Masonry

Chimney and Combined Vent Connector

MiNiMUM LENGTH =AS SHORT AS PRACTICAL

FOR MAXIMUM LENGTH SEE NOTE TO LEFT

APPLIANCE

CONNECTOR

INTERIOR TILE-L] NED

MASONRY CHIMNEY

NOTE- chimney must be property

sized par provided venting tables

or lined with listed metal lining

system,

SEALED FIREPLACE

OPENING

Note1 - Eithersingle-walledordouble.walledventconnectormaybeused.Referto thecapacity requirementsas shownIn the pro-

videdventing tables for InstallationsIn USAand the ventingtables In currentCAN/CGA-B141l.ffor installationsin Canada,

FIGURE t6

General Venting Requirements

All G24M furnaces must be vented according to these

instructions.

1 - Vent diameter recommendations and maximum al-

lowable pipingruns are found inthe providedventing

tables forthe USA, and the appropriateventingtables

in the standards of CAN/CGA B149.1 and B149.2 of

the Natural Gas and Propane Installation Code for

Canada,

2-In nocase shouldthe vent or vent connectordiameter

be less than the diameter specifiedin the provided

ventingtablesfor the USA, andthe appropriatevent-

ing tables in the standardsof CAN/CGA B149.1 and

B149.2 of the Natural Gas and Propane Installation

Code forCanada,

Page 13

3 - For single appliance vents: If the vertical vent or tile-

lined chimney has a larger diameter or flow area than

the vent connector, use the vertical vent diameter to

determine the minimum vent capacity and the vent

connector diameter to determine the maximum

vent capacity. The flowarea of the vedicelvent,how-

ever, shall not exceed 7 times the flow area of the

listedappliancecategorizedvent area, drefthcodout-

let area or flue cellar area unlessdesignedaccording

to approved engineeringmethods.

4 - For multiple appliance vents: The flowarea of the larg-

estsectionof vertical vent or chimneyshallnotexceed

7 times the smallest listed appliancecetegefized vent

area, drafthoodoutlet area or flue collararea unless

designed according to approved engineering meth-

ods.

5 - The entire length of single wall metal vent connector

shall be readily accessible for inspection, cleaning,

and replacement.

6 - Single appliance venting configurations with zero lat-

eral lengths, see tables 4 and 5, are assumed to have

no elbows in the vent system. For all other vent config-

urations, the vent system is assumed to have two 90°

elbows. For each additional 90° elbow or equivalent

(for example two 45° elbows equal one 90°elbow) be-

yond two, the maximum capacity listed in the venting

table should be reduced by 10 percent (0.90 x maxi-

mum listed capacity).

7 - The common venting tables 6, 7, 8, and 9 were gener-

ated using a maximum hodzontal vent connector

length of 1-1/2 feet (.46 m) for each inch (25 ram) of

connector diameter as follows:

TABLE 3

Connector

Diameter

inches (ram)

3(76)

4(102)

5 (127)

s(152)

7 (178)

Maximum Horizontal

Connector Length

feet (m)

4-1/2 (1.37)

s (1.e3)

7-tr2(2.29)

8 (2.74)

10-1/2 (3.20}

8 - If the common vertical vent is offset,the maximum

common vent capacity listed in the common venting

tables should be reduced by 20%, the equivalent of

two 90° elbows (0.80 x maximum common vent ca-

pacity). The hodzontal length of the offset shallnot ex-

ceed 1-1/2 feet (.46 m) for each inch (25 ram) of cem-

mon vent diameter.

9- The vent pipe should be as short as possible with

the least number of elbows and angles required to

complete the job. The vent connector should be

routed to the vent using the shortest possible route.

10- A vent connector shall be supported without any dips

or sags and shall slope aminimum of 1/4 inch (6.4

ram) per linear foot (305 mm) of connector, back to-

ward the appliance. See local and national installation

codes for support intervals and methods. National

installation code in the USA is current edition of Na-

tional fuel Gas Code (ANSI-Z223.1). National installa-

tion codes in Canada are current editions of CAN/

CGA-B149 codes.

11- Vent connectors shall be firmly attached to fumace

flue collars by screws or other approved means, ex-

cept vent connectors of listed type B vent material

which shall be assembled according to the manufac-

turer's instructions. Joints between sections of single

wall connector piping shall be fastened by screws or

other approved means.

12- When the vent connector used for Category I ap-

pliances must be located in or pass through a crawl-

space or other areas which may be cold, that portion of

the vent connector shall be constructed of listed

double-wall type B vent material or matedal having

equivalent insulation qualities.

13- All venting pipe passingthrough floors, walls, and ceil-

ings must be installed with the listed clearance to com-

bustible materials and be fire stopped according to lo-

cal codes. In absence of local codes, refer to NFGC

(Z223.1).

14- No portionof the venting system can extendinto,or pass

through any circulation air duct or plenum.

15- Vent connectors serving Category I appliances shall

not be connected to any portion of mechanical draft

systems operating under positive pressure such as

Category III or IV venting systems.

16- If vent connectors are combined prior to entering the

common vent, the maximum common vent capacity

listed inthe common venting tables must be reduced by

10%, the equivalent of one 90°elbow (0.90x maximum

common vent capacity).

17- The common vent diameter must always be at leastas

large as the largest vent connector diameter.

18- In no case, shall the vent connector be sized more

than two consecutive table size diameters over the

size of the draft hood outlet or flue collar outlet.

19- Do not install a manual damper, barometric draft regu-

lator or flue restdctor between the furnace and the

chimney.

20- When connecting this appliance toan existingdedicated

or common venting system,the venting system must be

inspected for signs of corrosion and general condition.

The sizing of the vent system must be reviewedand

mast conform to these instructions and the provided

venting tables for the USA, and the appropriate venting

tables in the standards of CAN/CGA B149.1 and

B149.2 of the Natural Gas and Propane Installation

Code for Canada. If the existing system is inconflictwith

these requirements, the venting system must be re-

sized.

Page 14

TABLE4

CAPACITY OF TYPE B DOUBLE-WALL VENTS WITH TYPE B DOUBLE-WALL CONNECTORS

Height Lateral

H L

(feat) (feet)

0

2

64

6

0

2

85

8

0

2

10 5

10

0

2

15 5

10

15

0

2

5

2O 10

15

20

0

2

5

30 10

15

2O

3O

MIN

0

13

21

25

0

12

23

28

0

12

23

30

0

11

22

29

35

0

10

21

28

34

48

0

9

21

27

33

56

NR

SERVING A SINGLE CATEGORY I APPUANCE

Vent and Connector Diameter - D (inches)

3 Inch 4 Inch I5 Inch

m

Appliance Input Rating In Thousands of Btu Par Hour

MAX

78

51

49

46

84

57

53

49

88

61

57

51

94

69

65

59

53

97

75

71

64

58

52

100

81

77

70

64

58

NR

MIN

0

18

3O

36

0

16

32

39

0

17

32

41

0

15

30

4O

48

0

14

29

38

46

55

0

13

28

37

44

53

73

MAX

152

97

94

91

165

109

103

98

175

118

f13

104

191

136

130

121

112

202

149

143

133

124

116

213

166

160

150

141

t32

113

MIN

0

27

39

47

0

25

42

51

0

23

41

54

0

20

39

51

61

0

18

38

5O

59

69

0

14

36

48

57

66

88

MAX

251

157

153

149

276

178

171

164

295

194

187

176

327

226

219

206

195

349

250

242

229

217

2O6

374

283

275

262

249

237

214

6 Inch

MIN

0

32

50

59

0

28

53

64

O

26

52

67

0

22

49

64

76

0

20

47

62

73

84

0

18

45

59

70

8O

104

MAX

375

232

227

223

415

263

255

247

447

289

280

267

502

339

330

315

301

540

377

367

351

337

322

587

432

421

405

389

374

346

NOTE: Singleapp/isnceventingconfiguraUonsv_Lhzero thtera/ton rutsare assumedtohave no elbow_in theventsystem,Forall otherventconfigurations,the vent

systemisassumed_ohave two90_elbows,Forea_ addifiona/90°elbowor equivalent(forexampletwo45°elbowsequalonegO° elbow) beyondP_o,themaximum

capacitylistedin the venting tableshouldbe reducedby 10 percent(0.90 x maximumlistedcapacity).

Page 15

Height

H

(feet)

10

15

20

30

TABLE 5

CAPACITY OF TYPE B DOUBLE-WALL VENTS WITH SINGLE-WALL METAL CONNECTORS

Lateral

L

(feet)

0

2

4

6

0

2

5

8

0

2

5

10

0

2

5

10

15

O

2

5

10

15

20

0

2

5

lO

15

20

30

MIN

38

39

NR

NR

37

39

NR

NR

37

39

52

NR

36

38

51

NR

NR

35

37

5O

NR

NR

NR

34

37

49

NR

NR

NR

NR

SERVING A SINGLE CATEGORY I APPLIANCE

Vent and Connector Diameter - D (inches)

3 Inch 4 Inch 5 Inch

Appliance Input Rating in Thousands of Btu Per Hour

MAX

77

51

NR

NR

83

56

NR

NR

87

61

56

NR

93

69

63

NR

NR

96

74

68

NR

NR

NR

99

80

74

NR

NR

NR

NR

MIN

59

6O

74

83

58

59

77

90

57

59

76

97

56

57

75

95

NR

54

56

73

93

NR

NR

53

55

72

91

115

NR

NR

MAX

151

96

92

89

164

108

102

95

174

117

111

100

190

136

128

116

NR

200

148

140

129

NR

NR

21t

164

157

144

131

NR

NR

MIN

85

85

102

114

83

83

107

122

82

82

105

132

80

8O

102

128

158

78

78

100

125

155

186

76

76

98

122

151

181

NR

MAX

249

156

152

147

273

176

168

161

293

193

185

171

325

225

216

201

186

346

248

239

223

208

192

372

281

271

255

239

223

NR

6 Inch

MIN

126

123

146

163

123

121

151

175

120

119

148

188

116

115

t44

182

220

114

113

141

177

216

254

110

109

136

171

208

246

NR

MAX

373

231

225

220

412

261

252

243

444

287

277

261

499

337

326

3O8

29O

537

375

363

344

325

306

584

429

417

397

377

357

NR

NOTE: Singleapp4ianoaver_ngconfigurationswithzero laterallengthsare assumedto havenoelbowsin the ventsystem.Forall othervent_figura_ons, the vent

ao

system isassumedtohavetwo90 eibow,_Fo_each ad_N_al _0°elboworequtva_t (f_ exampleIwo45 etoowsequalonegO=elbowJbeyondtwo.themaximum

capacitylistedin the ventingtable shouldbe reduced by 10 percent(0.90 x maximumlistedcapaclty_.

Page 16

Vent

Height

H

(feet)

6

8

10

t5

20

30

TABLE 6

VENT CONNECTOR CAPACITY

TYPE B DOUBLE-WALL VENTS WITH TYPE B DOUBLE-WALL CONNECTORS

Connector

Rise

R

(feet)

1

2

3

1

2

3

1

2

3

1

2

3

1

2

3

1

2

3

SERVING TWO OR MORE CATEGORY I APPLIANCES

MIN

22

23

24

22

23

24

22

23

24

2t

22

24

21

22

23

20

21

22

3 inch

MAX

37

41

44

40

44

47

43

47

50

50

53

55

54

57

6O

62

64

66

Vent and Connector Diameter - D (inches)

4 inch I 5 Inch

B

Appliance Input Rating in Thousands of Btu Per Hour

MIN

35

37

38

35

36

37

34

36

37

33

35

36

33

34

35

31

33

34

MAX MIN MAX

66 46 106

75 48 121

81 49 132

72 49 114

80 51 128

87 53 139

78 49 123

86 51 136

92 52 146

89 47 142

96 49 153

102 51 163

g9 46 157

105 48 167

110 50 176

113 45 181

118 47 190

123 48 198

MIN

58

60

62

64

66

67

65

67

69

64

66

68

62

64

66

6O

62

64

6inch

MAX

164

183

199

176

195

210

189

206

220

220

235

248

246

259

271

288

299

309

Vent

Height

H

(feet)

6

8

10

15

20

3O

TABLE 7

COMMON VENT CAPACITY

TYPE B DOUBLE-WALL VENTS WITH TYPE B DOUBLE-WALL CONNECTORS

SERVING TWO OR MORE CATEGORY I APPLIANCES

4 Inch

FAN+ FAN FAN+NAT

92 81

101 90

110 97

125 112

136 123

t52 138

Common Vent Diameter - D (Inches)

5 Inch 6 Inch 7 Inch

Appliance Input Rating in Thousands of Btu Per Hour

FAN + NAT

116

129

141

164

183

210

FAN + FAN

204

224

243

283

314

361

FAN + NAT

161

178

194

228

255

297

FAN ÷ FAN

3O9

339

367

427

475

547

FAN +FAN

140

155

169

195

215

244

FAN+NAT

248

275

299

352

394

459

Page 17

Vent

Height

H

(feet)

15

3O

TABLE 8

VENT CONNECTOR CAPACITY

TYPE B DOUBLE-WALL VENTS WITH SINGLE-WALL METAL CONNECTORS

Connector

Rise

R

(feet)

1

2

3

1

2

3

1

2

3

SERVING TWO OR MORE CATEGORY I APPLIANCES

MIN

NR

NR

NR

NR

NR

NR

47

5O

54

3 Inch

MAX

NR

NR

NR

NR

NR

NR

6O

62

84

Vent and Connector Diameter - D (inches)

4 Inch 5 inch

Appliance Input Rating in Thousands of Btu Per Hour

MIN

NR

NR

NR

79

83

87

77

81

85

MAX MIN MAX

NR NR NR

NR NR NR

NR 121 131

87 116 138

94 121 150

100 127 160

110 113 175

115 117 185

119 122 193

MIN

NR

168

174

177

185

193

169

177

185

6Inch

MAX

NR

182

198

214

230

243

278

290

30O

Vent

Height

H

(feet)

6

8

10

15

2O

3O

TABLE 9

COMMON VENT CAPACITY

TYPE B DOUBLE-WALL VENTS WITH SINGLE-WALL METAL CONNECTORS

SERVING TWO OR MORE CATEGORY I APPLIANCES

Common Vent Diameter * D (inches)

4 inch

FAN+ FAN FAN + NAT

89 78

98 87

106 94

121 108

131 118

145 132

5 inch 6 Inch

Appliance Input Rating in Thousands of atu Per Hour

FAN + FAN

136

151

163

189

208

236

FAN + NAT

113

126

137

159

177

202

FAN + FAN

200

218

237

275

305

350

FAN ÷ NAT

158

173

189

221

247

286

FAN ÷ FAN

304

331

357

416

463

533

7Inch

FAN + NAT

244

269

292

343

383

446

Removal of the Furnace from Common Vent

In the event that an existing furnace is removed from a

venting system commonly run with separate gas ap-

pliances, the venting system is likely to be too large to

properly ventthe remaining attached appliances. The fol-

lowing test shouldbe conducted while each appliance in

operation and the other appliances not in operation re-

main connected to the common venting system. If the

venting systemhas been installed improperly,the system

must be corrected as indicated in the general venting re-

quirements section.

1- Seal any unused openings in the common venting

system.

2-Visuallyinspectthe ventingsystemfor propersizeand

horizontal pitch. Deterrrmethere is no blockage or re-

striction, leakage,corrosion, or other deficiencies which

could cause an unsafe condition.

3-

4-

5-

Tothe extentthat it is practical, closeallbuilding doors

and windows and all doors between the space in

which the appliances remaining connected to the

common ventingsystemare located andotherspaces

of the building. Turn on clothes dryers and any ap-

pliancesnot connected to the commonventingsys-

tem. Turn on any exhaust fans, suchas range hoods

and bathroom exhausts, sothey willoperate at maxi-

mum speed. Do not operate a summerexhaustfan.

Close fireplacedampers.

Follow the lightinginstructions. Place the appliance

being inspected in operation. Adjust thermostat so ap-

pliance will operate continuously.

Test for spillage of flue gases at the draft hood relief

openingafter 5 minutesof mainburner operation.Use

the flame of a match orcandle, or smokefrom a ciga-

rette,cigar or pipe.

Page 18

6- Afterdetermining that each appliance remaining con-

nected to the common venting system prepedy vents

when tested as indicated in step 3, return doors, win-

dows, exhaust fans, fireplace dampers and any other

gas-burning appliance to their previous condition of

use.

7- If improper venting is observed during any of the

above tests, the common venting system must be cor-

rected. The common venting system should be re-

sized to approach the minimum size as determined by

using the appropriate tables in appendix G in the cur-

rent standards of the National Fuel Gas Code ANSI

Z223.1 in the USA, and the appropriate Category 1

Natural Gas and Propane appliances venting sizing

tables in the current standards of the CAN/CGA

B149.1 and B149.2 in the Natural Gas and Propane

Installation Code in Canada.

Horizontal Venting

Side Wall Venting Kit Widng

CX_3 CONTROL 8OX

MOTOR

THERMOSTAT CONNECTIONS

13ERMINAL IN FURN&CE

JUNC'RQN BOX

24 VAC

THERMC_TAT

.... FA_Y4NST_ED WI_NG

-- FIFJ.D-INSTALLED WIRING

FIGURE 17

This furnace design is certified by the American Gas

Association and the Canadian Gas Association for hori-

zontal venting through an outside wall only with the use of a

Field Conb'ols Company Model SWG-4L sidewall venting

kit available as Lennox part number 79J15. No other Field

brand venting kit or any other manufacturer's venting kit is

acceptable. Horizontal venting of this furnace without the

use of the above stated kit is prohibited. See figure 17 for

field wiring of side wall horizontal venting kit,

When horizontally vented, the minimum clearance for

termination from electric meters, gas meters, regulators

and relief equipment is 4 feet (1.2 m) for US installations.

Refer to the current CAN/CGA B149.1 and B149.2 for

installations in Canada or with authorities having localju-

risdiction.

At vent termination, care must be taken to maintain pro-

tective coatings over building materials (prolonged expo-

sure to exhaust condensate can destroy protective coat-

ings). It is recommended that the exhaust outlet not be

located within 6 feet (1.8 m) of a condensing unit because

the condensate can damage the painted coating.

Iiiiiiii_i_ii_lii!ii::i!iiiiii iii {iiil!i¢i!iiiTiiiiT{iiii!iiiiiiii{ii

GAS SUPPLY

1 - This unitisshipped standardfor left orright sideinstal-

lation of gas piping (or top entry in horizontal applica-

tions). Connect the gas supply to the piping assembly.

2- When connecting the gas supply, factors such as

length of run, number of fittings and furnace rating

must be considered to avoid excessive pressure drop.

Table 10 listsrecommendedpipe sizes for typicalaP-

plications.

The gas piping must not run in or throughair ducts,

clothes chutes, gas vents or chimneys,dumbwaiters

or elevator shafts,

3-

4-

5-

The pipingshould besloped 1/4 inch(6.4 ram) per 15feet

(4.57 m) upwardtowardthe meterfrom the fumace.The

piping must be supported at proper intervals [every 8 to

10 feet(2.44to 3.01 m) using suitablehangers or straps.

A drip leg should be installedin verUcalpipe runs to the

unit.

In some localities,codes may require installationof a

manuel main shut-off valve and union (furnished by

the installer) externalto the unit. Union must be of the

groundjointtype.

AIMPORTANT

NOTE -Install a 1/8 inch NPT plugged tap in the _eldpiping

u_m of _e gas supplyconnes_on_ the unit. The tap

must be accessiblefor testgaugeconnection._ee figure 18.

NOTE -In case emergencyshutoffis required, shutoff main

manual gas valve and disconnect main power to uniL These

devicesshou/d be propedylabeled by the installer.

Page 19

TABLE 10

GAS PIPE CAPACITY - FT3/HR (M3/HR)

Nominal Internal

Iron Pipe Size Diameter 10 20 30 i 40

inches (mm) inches (mm) (3.048) (6.096) (9.144) I (12.192

1/4 .364 43 29 24 20

(6.35) (9.246) (1113) (.52) (,65) (.57)

3/8 .493 96 65 52 45

(9.53) (12.522) (2.69) (t.84) (1.47) (1.27)

112 .622 175 t20 97 82

(12.7) (17.799) (4.95) (3.40) (2,75) (2.32)

3/4 .524 360 250 200 170

(19.05) (20.930) (10.t9) (7.08) (5,66) (4,81)

1 1.049 680 465 375 320

(25,4) (26.645) (919.25) (13.t7) (10.62) (9,06)

1-1/4 1,380 1400 950 770 660

(31.75) (38.052) (39.64) (26,90) (21.80) (18.69)

1-1/2 1.610 2100 460 tt80 990

(38,1) (40.894) (59A6) (41.34) (33,41) (26,03)

2 2,067 3950 2750 2200 1900

(50.8) (52.502} (111.85) (77,67) (62,30) (53,80)

2-1/2 2,469 6300 4350 3520 3000

(63,5) (67.713) (176.39) (123,17) (99.67) (84.95

3 3,068 11000 7700 6250 5300

(76.2) (77.927) (311.46) (216.03) (176.98) (150.07)

44.026 23000 15800 12800 10900

(101.6) (102.260) (65t.27) (447.39) (362,44) (308.64)

Length of Pipe -feet (m)

80 60 70 00 90 100

(15.240) (18.288) (21,336) (24.384) (27,432) (30.480)

18 16 15 14 13 12

(.51) (.45) (.42) (,40) (.37) (.34)

40 36 33 31 29 27

(1.13) (1.02) (.73) (.88) (,82) (.76)

73 66 61 57 53 50

(2.07) (1,87) (I,73) (1.61) (150) (1.42)

151 138 125 118 110 103

(4.28) (3.91) (3.54) (3,34) {3.11) (2.92)

285 260 240 220 205 195

(8,07) (7.36) (6.80) (623) (5.80) (5.52)

580 530 490 460 430 400

(16.42) (15.01) (13.87) (13.03) (12.18) (11.33)

900 810 750 690 650 620

(25,48) (22.94) [21.24) (19,54) (18.41) (17.56)

1680 1520 1400 1300 1220 1150

(47.57) (43,04) (39.64) (36,01) (34.55) (32,56)

2650 2400 2250 2050 1950 1850

(75.04) (67.96) (63.71) (58.05) (55,22) (52.38)

4750 4300 3900 3700 3450 3250

(134.50) (121.76) (110.43) (104.77) (97.69) (92.03)

9700 8600 8100 7500 7200 6700

(274,67) (249.13) (229,36) (212,37) (203,88) (189.72)

NOTE-Capacity given 3in cubic feet (m )of gas per hour and based on O,6Ospecific grav_ty gas.

MANUAL

MAIN SHUT-OFF

VALVE

(With I/6 _n.NPT "_I

Plugged Tap Shown)

JOINT

UNION

Left Side Piping

(Standard)

AUTOMATIC

GASVALVE

(v_t=manual

DRIPLEG

AUTOMATIC

GASVALVE

(withmanusl

valvai

FIELD

PROVIDED

AND INSTALLED

FIGURE 18

MANUAL

VALVE

Plugged Tap

Shown)

JOLNT

UNtON

_DRIP LEG

Right Side Piping

(Alternate)

Leak Check

After gas piping is completed, carefully check all piping

connections(factory-andfield-installed) forgas leaks.Use

a leak detectingsolutionor other preferred means.

ACAUTION

NOTE -In case emergency shutoff is required,shutoffthe

main manual gas valve and disconnect the mainpowerto

the furnace. These devicesshould be properly labeledby

the installer.

The furnacemust be isolatedfrom the gas supplysystem

by closingits individualmanual shut-off valve duringany

pressure testing of the gas supply system at pressures

equal to or/ess than 1/2 psig (3.48 kPa).

AIMPORTANT

MANUAL MAiN

SHUT,OFF VALVE

WILL NOT HOLD

NORMAL TEST

PRESSURE

c/_

ISOLATE

FIGURE 19

Page 20

l[l_[_i[_l i ii{iliiiiiii[iii{ii{ii}i{iiii{iiiiii}!{}i{ii{ii{i{{}i{iii}iiii{{i{i}ili{i}{i!{iI

ACAUTION

These units operate on 120 volt, single phase, 60 hz

electrical power. Refer to figure 20 for field wiring and

figure 22 for schematic wiring diagram and trouble-

shooting.

1 - Select circuit protection and wire size according to the

unit rating plate.

2 - Knockouts are provided on both sides of the fumaca

cabinet to facilitate widng.

3 - install the room thermostat according to instructions

provided with the thermostat.

4 - install aseparate disconnect switch (protected by ei-

ther fuse or circuit breaker) near the unit so power can

be turned off for servicing.

5 - Before connectJng the thermostat or the power widng,

check to make sure the wires will be long enough to

facilitate servicing at a later date. Remove the blower

access panel and open the panel to check wirelength

for access.

6 ° Complete wiring connectionsto the equipment using

wiringdiagram providedwithunit andwidngdiagrams

shown infigures 20 and 22. Use 18 gaugewire or larg-

er for thermostatconnections.

7 - Electricallygroundthe unit accordingto local codes or,

in the absence of local codes, according to the current

National Electric Code (ANSI/NFPA No. 70) for the

USA and current Canadian Electric Code part 1 (CSA

standard C22,1) for Canada.

NO TE- The G24M furnace contains electronic com-

ponents that are polarity sensitive. Make sure that

the furnace is wired correctly and is properly

grounded.

8 - One tine voltage accessory "ACC" terminal is provided

on the furnace control board with aprotective plastic

cap. Any accessory rated up to 4 amps can be con-

nected to this terminal(after removing the protective

cap) with the neutral leg of the circuitbeing connected

to the line voltage neutral wire. See figure 21 for con-

trol board configuration. This terminal is energized

whenever the blower is in operation.

9 - One line voltage heating accessory"HTG ACC" termi-

nal is provided on the fumaco control board with a pro-

tective plastic cap. Any accessory rated up to 4 amps

can be connectedto this terminal (after removing the

protective cap) with the neutral leg of the circuit being

connected to the line voltage neutral wire. See figure

21 for control board configuration. This terminal is en-

ergized in the heating mode whenever the blower is in

operation.

Indoor Blower Speeds (Refer to Figure 22)

1-When the thermostat is set to "FAN ON", the indoor

blowerwill runcontinuouslyon low speedwhen there

is no coolingor heatingdemand.

2 - When the G24M is running inthe heatingmode, the in-

doorblowerwillrun on the heatingspeed.

3 - When there is a coolingdemand,the indoorblowerwill

run on the coolingspeed.

Page 21

TYPICAL G24M FIELD WIRING DIAGRAM

(120V, 1PH, 60HZ)

-- -- -- FIELD iNSTALLED CLASS I124V

-- FIELD INSTALLED LiNE VOLTAGE

THE MO TAT

I

I

I

I

I

PRESSURE SWITCH @

PRIMARY LIMIT

@ ®

FLAME ROLLOUT SWITCHES

I I

II

Y G W R

8UREUGHT CONTROL

SECONOARY

UMrrS

@@ a

4_

DOOR

INTERLOCK

_NrrCH

120V,1PH,60 HZ

L1 GNO

i '

BLACK

WHITE

FIGURE 20

50A62 SureLIght _INTEGRATED CONTROL BOARD

(Silicon Nltride Ignition System)

÷,=- _, _ "=,=÷-- .__

0_ I I I II 0Ill1

-- NEJ_AI._ --

SI-I Iii-I 'rIME m

G'I QN II0 _ fIN III If'p"

i

iI

=. .... J

L. ...........

II

JYEW R C

YG WR C

TERMINAL DESIGNATIONS

ACB COOL

ACB HEAT

PARK

ACB LOW

ACC

TX

HOT

HTG ACC

NEUTRALS

24VAC HOT

24VAC RTN

FLAME SENSE

Blower - Cooling Speed ILlne Volt)

Blower -Heating Speed (Line Volt)

Alternate Blower Speeds (Dead)

ContinuousLow Speed Blower

Accessory Terminal (Line Volt)

120VAC Hot to Transformer

120VAC Hot Input

Heat Only Accessory (Line Volt)

120VAC Neutrals

24VAC Hot from Transformer

24VAC Return from Transformer

Rame Sense Terminal

FIGURE 21

Page 22

IZoV

OR

Nm

LI"_''"'b_ J,

G24M Schematic Wiring Diagram

(120V, 1PH, 60HZ)

_._,,_ _;_ __

I

SiO _

LIU_T

IZlS47 (13147

U_lrITS1 _IrZTC_ 1

|

SECgI_ff

LIMITS

&,

11)_1 121521

r--'l /\

III I

?_q; , ,

B3

-_ II "_

/j.

-ff ClRI_JIT Tp./_ISFORKER

1 OWa/_Bq

,,-_.L. .,..L :T

S_T _AT HEAT A_rlCIPAT,0N ROOM

FO_ I_ld SLclqIESLimITSb.S 4_L.LO_, $1 _AT

NF,4ITI_HO_RS t/ALOE... 0.5

VALISE..... 0.7

LINE "_-TA_ FIELD II_TALLI_

.... CLASS 11 Y_I.TA_ FIELD WllqlN6

0_40T1_ OPTIO_d-

TI _COk_l O_ i_

,_ [III_MI"- _ZC S40_ HADIID,CAH CAb_ INJUR'r

TO PRE_IT HOT_ BLR4OLR, QRDF_IH.LINIT KIST IE _IN _OR_U4CIE

I_=_'1__0f414£_ _ _ ,_ III I 12 ARE _ _l'r;4 NATIQN/L id40 LIO¢,_*.CLOGS.

Gb_ _dOT_ _ 10 A_Y "n_dIffiUJ.ALL _MOTOR

ONE I_IECT ION N_-'T _1_PiC_KEOOr#il OR MZ*

,_ FDRPRQP.M4FJLp M_.y NOTE-

IF ANY _IRE IN 1Tllli /_PLIM, I¢_ IS F_wz,J_Cl_,[T

ii_ _AEFU,I_ _TH 111_E0F LIKE SIZ£

RATll4O b4_ II4_q.ATIOH "IHICXI4_S.

FIGURE 22

Page 23

iU_tiS_U_!_i_i_iiii!i_ii!i_i_i_i_i_i_i_iiiii_i_i_i_i_i_:i_i_i_i_i_i_i_i_i_i_i_ii_ii_iiii!i_iiiii_iii_ii_i_i_}_i_i_i_i_i_i_iii_i_i_i_i_iii_i

,WARNING

&WARNING

,CAUTION

FOR YOUR SAFETY READ BEFORE LIGHTING

BEFORE LIGHTING smell all around the appliance areafor

gas. Be suretosmell next to the floorbecause some gas is

heavier than air and will settleon the floor.

Use onlyyour hand to turn the gas controlknob.Neveruse

tools.Ifthe knobwillnot turnby hand,donot _3_to repairit,call

a qualifiedservicetechnician.Force or attemptedrepairmay

resultin afire or explosion.

Placing Furnace Into Operation

G24M furnaces are equipped with a SureUght" ignition

system. Do not attemptto manuallylightburnerson these

furnaces. Each time the thermostatcallsfor heal the bum-

ere will automaticallylight.

Gas Valve Operation (Figures 23 and 24)

1-STOP! Read the safetyinformation at the beginning of

this section.

2 - Set the thermostatto the lowest setting.

3-Turn off all electricalpower to the unit.

4 - This furnace is equippedwithan ignitiondevicewhich

automaticallylightsthe burners. D° not t_ to lightthe

burnersby hand.

5-Remove the access panel.

6-

7-

White Rodgers 36E Gas Valve -Switch gas valve le-

ver to OFF. See figure 23.

Honeywell VR8205 Gas Valve - Turn knob on gas

valve clockwise4_' to OFF. Do not force. See figure

24.

Wait five minutes to dear out any gas. If you then smell

gas, STOP! Immediately call your gas supplier from a

neighbor'sphone. Followthe gas supplier'sinstructions.

If you do not smell gas go to next step.

WHITE RODGERS 36E Series Gas Valve

MANIFOLD

PRESSURE

ADJUSTMENT

0o/SCREW

MANIFOLD

PRESSURE

/OUTLET

GAS VALVE SHOWN IN OFF POSITION

FIGURE 23

HONEYWELL VR8205 Series Gas Valve

MANIFOLD

PRESSURE -_

SCREW MAN,FOLD

PRESSURE

OUTLET

GAS VALVE SHOWN IN OFF POSITION

FIGURE 24

8 - WhiteRodgers 36E Gas Valve-Switchgas valvelever

to ON.

Honeywell VR8205 Gas Valve -Turn knobongasvalve

counterclonkwise_l_to ON. Do not force.

9-Replace the access panel.

10 - Turn onall electricalpower to the unit.

11- Set the thermostatto desired setting.

NOTE- When unitis inifia//ystaffed,steps1 _reugh 11

may need to be repeated to purge airfrom gas line.

12 - If the appliance will not operate, follow the instructions

"Turning Off Gas to Unit" and callyour servicetechni-

dan or gas supplier.

Turning Off Gas to Unit

1 - Set the thermostatto the lowest setting.

2 - Turnoffallelectricalpowerto the unitif serviceis tobe

performed.

3 - Remove the access panel.

4 - White Rodgers 36E Gas Valve -Switch gas valve le-

ver to OFF.

Honeywell VR8205 Gas Valve -Turn knob on gas

valve clockwise411_to OFF. Do notforce.

5 - Replace the access panel.

Page 24

HeatingSequenceOfOperation

1- Whenthermostatcallsforheat,combustionairblower

starts.

2 - Combustion air pressure switch proves blower opera-

tJon.Switch is factory set and requires no adjustment.

3 - After a 15 second prepurge, hot surface ignitor ener-

gizes.

4 - After a 20 second ignitor warm-up period, gas valve

solenoid opens.

5 - Gas is ignited, ignition sensor proves the flame and

combustion process continues.

6 - If flame is not detected after first ignition tdat, ignition

controlwillrepeat steps3and4fourmoretimesbefore

lockingoutthe gasvalve ("WATCHGUARD"flame fail-

ure mode). Ignitioncontrolwill then automatically re-

peat steps 3, 4, 5 and 6 after 60 minutes,

7- To interruptthe 60-minute °WATCHGUARD" pedod,

move thermostat_om "Heat" to "OFF" then back to

"Heat." Heatingsequencethen restartsat step f.

: • :. . • . . :::_ • : . ,: :::_:_:: _:::::: ;}::;:_::: :::::: ;_:1;'_:_:::::

Gas Flow

Tocheck for propergasflow to the combusf_onchamber,de-

terrninethe Bto(kW)klputfrom the unit ratingplate.Dividethis

inputraSngby the Btu (kW) per cubicfoot (cubicmeter)of

availablegas,The resultis the requirednumberof cubic feet

(cubicmeter)perhour.Determinethe flowof gas through the

gas meterfor two minutesend multiplyby 30 to get the houdy

flowof gas.

Gas Pressure

1 - Check the gas line pressure withthe unitfiringat maxi-

mum rate.A minimum of 4.5 in. w.c.for naturalgas or

11.0 in.w.c,forLP/prepanegas shouldbe maintained.

2- After the line pressure has been checked and ad-

justed, check the regulator pressure. Manifold pres-

suresare given in table 11. See figures23 and 24 for

manifoldpressureadjustmentscrewlocation.

Note -A natura! gas to LP/propane gas changeover kit is

requiredto convert the unit.

Refer totable 11 for manifoldpressure settingsfor installa-

tionsat differentaltitudesandfor differentfuels.

TABLE 11

MANIFOLDABSOLUTEPRESSURE(OUTLET}IN. W,C,(KPA)

Altitude - feet (m) above sia level

0-2000 2000-4500 4500-5500 5500-6500 6500-7500

FUEL (0-610) (610-1372) (1372-1676) (1676-1981) (1981÷2286)

3.5 3.5 (0,87)* 3.4 (0.85) 3,3 (0.82) 3.2 (0.80)

NAT (0.87)

6.6 6.5 (2.36)" 92 (2/29) 8,9 (221) 8.6 (2.14)

LP (2.36)

*No adjustment required.

NOTE -In Canada, certification for installations at eleva-

tions over 4500 feet (1372 m) is the jurisdiction of local au-

thorities.

The combustion air pressure switches are factory-set and

require no adjustment.

At elevations of 4500 feet (1372 m) or greater, replace the

factory-installed pressure switch with the switch listed in

table 12.

Unit Model

G24M-45

G24M-60

G24M-75

G24M-100

G24M-120

G24M-14_?

TABLE 12

Pressure Switch

Part Number

NO CHANGE

NO CHANGE

88J8001

18L2401

18L2401

NO CHANGE

Primary and Secondary Limits

The primarylimitis locatedon theheatingcompadmentves-

tibulepanel.Two secondarylimitsere locatedinthe blower

compartment,behind the blower.Theselimitsarefactory-set

andrequire no adjustment.

Flame Rollout Switches (Two)

These manuallyreset switchesare locatedjust abovethe

burnerbox. If tdpped,a check for adequatecombustion air

shouldbe made before resetting.

Combustion Air Pressure Switch

The combustion air pressureswitchis locatedonthe heat-

ing compartmentvestibule panel. This switchchecks for

proper combustion air blower operation before allowing

ignitiontrial,The switchis factory-setand requiresno ad-

justment.

Fan Control

The fan on time of 45 seconds is not adjustable. Fan off

time (time thatthe bloweroperates afterthe heat demand

has been satisfied) can be adjusted by flipping the dip

switcheslocated on the Surelightintegrated control.The

unitis shippedwitha factoryfan off settingof 90 seconds.

Fan off time will affect comfortand is adjustableto satisfy

individualapplications.See figure25.

Page 25

FAN-OFFTIMEADJUSTMENT

60sec. 90sec. 120sec. 180sec.

To adjust fan-off timing,flip dip switch to desired setting,

FIGURE 25

Temperature Rise

Check the temperature rise and, if necessary, adjust the

blower speed to maintainthe temperature rise withinthe

range shown on the unit ratingplate.

Thermostat Heat Anticipation

Set the thermostatheat anticipation:

0,50 amps White Rodgers gas valves

0.70 amps Honeywellgas valves

Electrical

1 - Check all wiring for loose connections.

2 - Check for the correctvoltage at the furnace (furnace

operating).

3-Check amp-draw on the blowermotor.

Motor Nameplate Actual

Blower Speeds

NOTE -CFM readingsare taken externalto unit with a dry

evaporator coiland withoutaccessories.

1 - Turn off electricalpower to furnace.

2-Remove unitaccess panel.

3 - Disconnectexistingspeedtap at control board speed

terminal.

NOTE -TERMINATION OF ANY UNUSED MOTOR

LEADS MUST BE INSULATED.

4 - Referto blower speedselectionchartonunitwidngdia-

gramfor desiredheatingor coolingspeed.

5 - Connect selected speed tap at control board speed

terminal.

6 - Resecure unitaccess panel.

7 - Turn on electricalpower to furnace.

Electronic Ignition

The SureLightTM integratedcontrolhas an addedfeatureof

an internalwatchguardcontrol.Thefeatureservesasan au-

tomaticresetdevicefor ignitioncontrolslocked-outbecause

the burnerhas failed to lighLThistype ofnuisancelockoutis

usuallyattributedto lowgas line pressure.Afterone hourof

continuousthermostatdemandforheat,the watchguardwill

break and remake thermostat demand to the furnace and

automaticallyreset the controlto relightthe furnace.

Flue And Chimney

1- Checkfluepipe,chimneyandall connections for tight-

ness and to make sure there is no blockage.

2 - Check unit forproper draft.

3 - Is pressureswitchclosed?Obstructed flue wi]]cause

unittoshutoffat pressure switch.Check flue and out-

letfor blockages.

4 - Reset manual flame rollout switches on burner box

cover.

Burner Flame Adjustment

The G24M burner flame is not adjustable; however, the

flame shouldbe inspectedat the beginning of each heating

season. If necessary,clean the burners.The burnerflame

shouldbe blue when burning naturalgas, and blue/yellow

when burningpropanegas. See figure 26.

Burner Flame

FLAME APPEARS BLUE IF

BURNING NAT. GAS; BLUE/

YELLOW FOR PROPANE,

-- VEST

PANEL

FIGURE 26

Turbulator

G24M(X) sedes unitsinclude a ceramic fiber turbulator in

each heat exchanger inlet. The turbulators lower nitrogen

oxide emissions.Prior to unit start-up, inspect the turbula*

tors for shipping damage. The turbulators are fragile; they

should be removed only if it is necessary to replace them.

Failure To Operate

If the unitfails to operate,check the following:

1 - Is the thermostatcallingfor heat?

2- Are access panelssecurely in place?

3 - Is the main disconnectswitchclosed?

4 - Is there a blownfuse?

5- Is the flltardirtyer plugged?Dirtyor ptuggedfilterswill

cause the limit controlto shutthe unitoff.

6 - Is gas turnedonat the meter?.

7-Is the manual mainshut-offvalve open?

8 - Is the internalmanual shut--offvalveopen?

9-Is the unitignitionsystem in lockout? If the unitlocks

outagain, call the servicetechnician to inspectthe unit

for blockages.

Page26

,CAUTION

At the beginning of each heating season, service items A

through E as described below:

A-Electrical

1 - Check all widng for loose connections.

2 - Check fur the correct voltage at the furnace (furnace

operating).

3 - Check amp-draw on the blower motor.

Motor Nameplate Actual

B-Blowers

Check the blower wheels for debris and cleanif necessary.

The blower motors are prelubdcated for extended bearing

life. No further lubrication is needed.

C-Filters

All G24M filters are installed external to the unit. Filters

should be inspectedmonthly. Clean or replace the filters

when necessary to ensure proper furnace operation.See

table 13 for filter sizes. Replacement filters for

G24M.-45/60/75 unitsmust have a minimumvelocityrating

of 400 FPM. Replacement filters for G24M-1OO/120/140

unitsrequirea minimum velocity ratingof 625 FPM.

TABLE t3

Model Number

G24M-45/60/75

G24M-100/120/140 IFilter Size -Inches (ram)

16 X 20 X 1 (406 X 508 X25)

20 X 20 X 1 (508 X508 X25)

AWARNING

D - Flue And Chimney

Check the flue pipe, chimneyand all connectionsfor tight-

ness and to make sure there is no blockage.

E-Burners

Inspect the burners and burner flame at the beginning of

each heatingseason.If necessary,clean the burnersas in-

dicated below:

1 - Turn off the electdcal and gas supplyto the furnace.

2- Remove the burner boxtop.

3 - Remove the burner retaining bracket,

4 - Remove the burners,

5 - Clean the insideof each bumer with a bottle brush as

shown infigure 27.

Cleaning Burners

BOTTLE

BRUSH

FIGURE 27 I

6- Replace the burners and the burner retaining bracket.

Make sure the burners are propedy seated in the slots

on the tray. The burner orifice must be aligned with the

manifold.

7-

8-

Reinstall the burnerbox top.

Restoreelectrical power andgas supply to the furnace.

Follow lighting instructions on the front of the unit.

Check the appearance of the burner flame, burner

pressure, gas flow, and temperature rise. If necessary,

make adjustments. See the other unit adjustments sec-

tion.

Heat Exchanger

Pedodicelly inspect the heat exchanger tubesand the flue

boxfor corrosionandsootdeposits.If necessary,cleanas

indicatedbelow:

1-Turn off the electricaland gas supplyto the furnace.

2 - Disconnectthe wiringto the combustionairfan.

3 - Remove the screws securingthe flue box to the furnace.

Clean the flue box with a wire brush (brass-bd_e brush

recommended),and rags or ashop vacuum cleaner.

4 - Disconnect the gas supplypiping and the ignitor and

sensor wires. Remove the burner assembly from the

furnace.

5- Sincethe heat exchangertubesare crimpedinseveral

locations, a thoroughdeaning of the entire lengthof

each tube is not possible. However,removeany soot

deposits whichare accessible witha wire brush (brass-

bristlebrushrecommended),andrags orashopvacuum

cleaner.

6 - Reinstallthe flue box using anew gasket.

7-Reconnectthe combustionair fan wiring.

8 - Reinstall the burner box, ignitor and sensor wires and

the gas supply piping.

9 - Carefully check all piping connections(factory andfield)

for gas leaks. Use a leak detec_ngsolutionor other pre-

ferrad means.

AIMPORTANT

10 Restore electricalpower and gas supply.Followlight-

ing instructionson front of unit. Check burner flame

and adjustif necessary.

Page 27

l_!_ _ _!_iiiiiiiiiiiiii!iiiiiiiiiiiiiii;i;;ilil;;il;illii iiiiiii iili i i i!ii;iiiiii;i;i;iii!i;i!!;!iii!il;iii;ii;iiiiiiiiiiiiiiiiiiiiiiiiiiii!iiiiiii_iiii!i_i_Ji_%_

The following repairpartsare availablethroughindependentLennoxdealers. When ordenngparts, includethe coreplet_furnace model numberlistedon the

A.G.A. or C.G.A. rating plate -- Example: G24M3-75. Refer to page 3 for parts iderdification.

CABINET PARTS

Front acoess panel

Blower access panel

Cabinet cap

Cabinet bottom

Vent adapter

ELECTRICAL PARTS

Transformer

Controlboard (Hot Sudace Ignition)

Door interlock switch

BLOWER PARTS

Blower wheel

Motor

Blower housing cut-off plate

Motor capacitor

HEATING PARTB

Heat exchanger

Main burners

Main burner orifices

Gas manifold/Burner box assembly

Gas valve

NOx turbulator [60 Hz, X units only)

Hot Surface Ignitor

Flame roliout switch (two)

FJame sensor

Primary limit

Secondary limit (two)

Pressure switch

Wire harness plug il cap

Flue box

Combustion air blower

Gaskets

Low gas pressure switch (propane only)

_ -,,_,-.----.-.--- _ .-._--_.-- ___..-_ --.-_,K_----_--_ .-- _--_._............ ........................................................ : : ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::;::::

DIAGNOSTIC CODES

LED #1

SIMULTANEOUS

SLOW FLASH

SIMULTANEOUS

FAST FLASH

SLOW FLASH

OFF

ALTERNATING

SLOWFLASH

SLOW FLASH

ON

ON

ON

OFF

FAST FLASH

SLOW FLASH

ALTERNATING

FAST FLASH

LED #2

SIMULTANEOUS

SLOW FLASH

SIMULTANEOUS

FAST FLASH

ON

SLOW FLASH

ALTERNATING

SLOW FLASH

OFF

SLOW FLASH

ON

OFF

ON

SLOW FLASH

FAST FLASH

ALTERNATING

FAST FLASH

DESCRIPTION

Power on - Normal operation.

Also signaled dudn,qcoolingand continuousfan.

Normal operation-signaled when heating demand initiatedat

thermostat,

Primary or secondary limit switch open.

Pressure switchopen or has opened 5 times duringa single call for heat;

OR: Blocked inlet/exhaustvent; OR: Condensate line blocked;

OR: Pressure switch closed priorto activationof combustionair blower.

Watchguard -- burners failed to ignite.

Flame sensed without gas valve ensr_lized.

Rollout switch open. OR: 9-pin connector improperly attached.

Circuit board failure or control wired incorrectly.

Main power polariW reversed. Switch line and neutral.

Low flame signal Measures below .7 microAmps. Replace flame sense rod.

Improper main gmuna or line voKageeelow/_ volts;

OR: Broken ignitor;OR: Open ignitorcircuit.

NOTE -Slow flash equals 1 Hz (one flash per second), Fast flash equals 3Hz (three flashesper second).

Minimum flame sense current =0.15 microAmps.

Page 28

iiiiiiiiiiiiiiiiiiiiiiiiiilli!iliiiiiii!iiiii!i!i!ii!i!iiiiii iiiii iiiiiiiii!iii i!i iii i i i i i i;i ili!iiiii!iiiiiiiiiiiii!_ii_iiiii!_!_!_iiiiiiiiiii_iiiiii_i_i_i_i_iii_i_i_iiiiiii_i_i_iiiii!i!i_i_i_iii!iii_i_i____iiiiiiiiiii_ii__iiii

HEATING SEQUENCE OF OPERATION

NORMAL HEATING MODE ABNORMAL HEATING MODE

POWER ON ]

No

I CONTROL SELF-CHECK OKAY?

I COMBUSTION AIR SLOWER ON FOR I SECOND. I

TURN INDUCER ON FOR 1 SECOND. I_

I IS POLARITY REVERSED?

GAS VALVE OFF. COMBUSTION AIR BLOWER OFF.

INDOOR BLOWER DELAY OFF.

LED#1 ON

LED #2 ON

(RESET CONTROL BY TURNING MAIN POWER OFF,)

POLARITY REVERSED.

LED #1 -FAST FLASH

LED #2 -SLOW FLASH

ISIGNAL IMPROPERI / NO

GROUND AT LED NO •NO

SIGNAL HOLDS _1 IS THERE I YES I S VOLTAGE _ LOW VOLTAGE SIGNAL AT LED HOLDS

UNTIL UNIT IS "_1 PROPER GROUND?r_I ABOVE 75vOLTS? _ UNTIL VOLTAGE RISES ABOVE75 VOLTS'I

PROPERLY

GROUNDED. NO I GAS VALVE OFF. COMBUSTION AIR BLOWER OFF, I

ROLLOUT SWITCH CLOSED_ il INDOOR BLOWER OFF WITH DELAY. I

"_ll" I•t'il'_ I LED #1 - ON. LED #2 - SLOW FLASH. I

YES I | SEQUENCE HOLDS UNTIL ROLLOUT SWITCH CLOSESt

GAS VALVE OFF. COMBUSTION AIR BLOWER ON,

NO

I

INDOOR BLOWER ON HEATING SPEED. I

LED #1 - SLOW FLASH I

LED #2 - OFF

GAS VALVE OFF.

COMBUSTION AIR BLOWER OFF.

INDOOR BLOWER OFF WITH DELAY

LED #1 OFF

I LED #2 SLOW FLASH

(Sequence ho_dsuntil pressure switch

closes or thermostat resets contmt.)

PRESSURE SWITCH WATCHGUARD MODE. IT

GAS VALVE OFF. COMBUSTION AIR BLOWER OFF.I I

INDOOR BLOWER OFF WITH DELAY. r-

LED #1 -- OFF. LED #2 - SLOW FLASH. |

IS S-MINUTE RESET PERIOD COMPLETE? l

[BURNER OFF?

(CONTINUOUS FLAME CHECK)

YES

NORMAL OPERATION: I

LED #1 - SLOW FLASH

LED #2 - SLOW FLASH

+

THERMOSTAT CALLS FOR HEAT:

LED #1 - FAST FLASH

LED #2 - FAST FLASH

YES i

I IS COMBUSTION AIR I

PRESSURE SWITCH OPEN? I-

YES

IIS COMBUSTION AIR BLOWER ENERGIZED? I

(HTG. ACC. ENERGIZED WITH CAB.) =,I

YES _

I HAS COMBUSTION AIR PRESSURE

SWITCH CLOSED IN 2.5 MINUTES?

YES

15-SECOND COMBUSTION AIR BLOWER PREPURGEI

INITIATED BY CLOSED PRESSURE SW TCH. /

YES _

CONTINUED NEXT PAGE

Page 29

HEATINGSEQUENCECONTINUED

NORMALHEATINGMODE ABNORMALHEATINGMODE

15-SECOND COMBUSTION AIR BLOWER PREPURGF I11

N T ATED BY CLOSED PRESSURE SW TCH. /

YES

[ IGNITOR WARM-UP -- 20 SECONDS. I

YES _

4-SECOND TRIAL FOR IGNITION.

GAS VALVE OPENS. IGNITOR ENERGIZED FOR

I SECOND AFTER VALVE OPENS.

NO FLAME SENSED DURING THIS PERIOD.

YES

I FLAME STABILIZATION PERIOD. I

4 SECONDS _

FLAME RECTIFICATION CURRENT CHECK /

CAN FLAME BE PROVEN WITHIN 4 P

SECONDS AFTER GAS VALVE OPENS?

( > 0.15 microamps)

FLAME PRESENT? I--_

YES _ NO_[

FLAME SIGNAL ABOVE 0.7 MICROAMPS?

YES _

I

IINDOOR BLOWER ON DELAY BEGINS /

/45 seconds.)

YES _

[INDOOR BLOWER ON ACB HEAT SPEED. 1ACC. TERMINAL ENERGIZED

PRIMARY AND SECONDARY LIMIT I

SWITCHES CLOSED? I

YES 1

._GAS VALVE OFF. COMBUSTION AIR BLOWER ON. _O

INDOOR BLOWER OFF.

HAS CONTROL FAILED TO SENSE FLAME FOR

FIVE CONSECUTIVE TRIES DURING A SINGLE

HEAT DEMAND?

/

IGNITION WATCHGUARD MODE. GAS VALVE OFF. I .

COMBUSTION AIR BLOWER OFF, I y_S_YES

INDOOR BLOWER OFF WITH DELAY

LED #1 - ALT, SLOW FLASH, LED #2 - ALT. SLOW FLASH,

S60-M NUTE RESET PER OD COMPLETE? /

/

YES T

HAS CONTROL RESET IGNITION I

SEQUENCE FOUR TIMES?

LOW FLAME SIGNAL |

(Does not affect operation of control) J

LED #1 - SLOW FLASH

LED #2 - FAST FLASH

GAS VALVE DE-ENERGIZED.

COMBUSTION AIR BLOWER DE-ENERGIZED.

INDOOR BLOWER ON UNTIL SWITCH CLOSES.

LED #1 - SLOW FLASH. LED #2 - ON.

IS LIMIT SWITCH CLOSED?

LIMIT SWITCH WATCHGUARD MODE.

GAS VALVE OFE COMBUSTION AIR

BLOWER OFF.

INDOOR SLOWER OFF WITH DELAY

LED #1- SLOW FLASH, LED #2 - ON.

YES

NO L IS 60-MINUTE RESET PERIOD

IROLLOUTyEsSWITCH_CLOSED? _ [ COMPLETE?

/ HAS PRIMARY/SECONDARY I ,

LIMIT AUTOMATIC RESET TIME I

I-.--I COMBUSTION AIR PRESSURE EXCEEDED 3 MINUTES? I

l SWITCH CLOSED?

/ GAS VALVE OFF. COMBUSTION AIR BLOWER OFF.

YES fINDOOR BLOWER OFF WITH DELAY.

ILED #1 - ON. LED #2 - SLOW FLASH.

I THERMOSTAT DEMAND SATISFIED. I LSEQUENCE HOLDS UNTIL ROLLOUT SWITCH CLOSES

YES

I {,_) #1 & #2 SIMULTANEOUS SLOW FLASHES. I

YES

COMB. AIR BLOWER CONTINUES 5-SECOND

POST PURGE AFTER T'STAT DEMAND IS SATISFIED.

INDOOR AIR BLOWER COMPLETES SELECTED

OFF" DELAY BEFORE SHUTT NG OFF.

;70

-S

NO

GAS VALVE DE-ENERGIZED.COMBUSTION AIR BLOWER ON. ]

INDOOR BLOWER OFF WITH DELAY IYES=

LED #1 - OFF. LED #2 - SLOW FLASH.

HAS CAB SWITCH CLOSED IN 2.5 MINUTES? |

NO

I5-MINUTE PRESSURE SWITCH I

WATCHGUARD MODE.

Page 30

COOLINGSEQUENCEOFOPERATION

NORMAL COOLING MODE ABNORMAL COOLING MODE

IPOWER ON I

IIGNITION CONTROL_MAIN POWER ON. I

I CONTROL SELF DIAGNOSTIC CHECK.IS CONTROL OPERATING NORMALLY?

YES _

I TURN INDUCER ON FOR 1 SECOND. I

i

YES _,

I IS POLARITY REVERSED? i= -

SIGNAL IMPROPER

GROUND AT LED.

SIGNAL HOLDS

UNTIL UNIT IS

GAS VALVE OFF. COMBUSTION AIR BLOWER OFF. I

INDOOR BLOWER OFF WITH NORMAL DELAY. I

SIGNAL CIRCUIT BOARD FAILURE AT LED.

INTERRUPT MAIN POWER TO RESET CONTROL,

SIGNAL POLARITY REVERSED AT LED.

IS THERE IYES..I IS VOLTAGE _ LOW VOLTAGE SIGNAL AT LET HOLDS

"'"_1 PROPER GROUND?I_" _ABOVE 75 VOLTS? !_1--_1 UNT LVOLTAGE R SES ABOVE 75 VOLTS.

PROPERLY I

GROUN.DEEL

IUoU;'

YES NO

I CHECK FOR MAIN BURNER FLAME SENSE.

IS MAIN BURNER FLAME OFF? I_1_-

I LED:SLOWFLABH TEREMAINSUNC NOEDITHROUGHOUT COOLING CYCLE.

I THERMOSTAT CALLS FOR COOLING. I

COMPRESSOR CONTACTOR AND SYSTEM FAN

ENERGIZED WITH 0-SECOND DELAY.

ACB COOL SPEED ENERGIZED. ACC. TERM. ENERG ZED.

GAS VALVE OFF. COMBUSTION AIR BLOWER OFF.

INDOOR BLOWER OFF WITH NORMAL DELAY,

SIGNAL CIRCUIT BOARD FAILURE AT LED,

SEQUENCE HOLDS UNTIL ROLLOUT SWITCH CLOSES.

GAS VALVE OFF, COMBUSTION AIR BLOWER OFF.

INDOOR BLOWER OFF WITH NORMAL DELAY.

SIGNAL CIRCUIT BOARD FAILURE AT LED,

SEQUENCE HOLDS UNTIL FLAME IS NOT SENSED.

THERMOSTATOPENS. I

COMPRESSOR OF_ I

SYSTEM FAN AND ACC. TERM. OFF I

WITH 0-SECOND DELAY. I

Page 31

• . . .................................................................................. •.......... ,.................................................... •..................... .......

...................... ..... ...................................................................................... :+_:+.:_:+:_.,..:.:.:+:,:,_._._:._::_:_.................... ::::::::_:+_::_:::::_::_:::::_i%_::

CONTINUOUS LOW SPEED FAN SEQUENCE OF OPERATION

I

I

I

_NO

THERMOSTAT CALLS FOR COOLING.

_1 YES

SYSTEM FAN SWITCHED TO ACB COOL

SPEED. ACC. TERM, REMAINS ON.

ILED:SLOWFLASHRATEREMAINS I

UNCHANGEDTHROUGHOUTSEQUENCE. I

MANUALFANSELECTIONMADEAT THERMOSTAT.

CONTROL (G) ENERGIZESSYSTEMFANAT CONTINUOUS

ACBLOWSPEED.ACC,TERM.ENERGIZED.

ITHERMOSTAT CALLS FOR HEAT (W),

I

HTGACC.TERM.ENERGIZES1

WITH COMB.AIR BLOWER. I

YESI

SYSTEM FAN ENERGIZES ON ACB HEAT SPEED

AFTER NORMAL DELAY

THERMOSTATOPENS.

THERMOSTAT OPENS.

_._ I SYSTEM FAN OFF, ACC. TERM. OFF.

I /AFTER OFF DELAY COMPLETED)./

MANUAL FAN SELECTION MADE AT THERMOSTAT. !It

CONTROL (G) ENERGIZES SYSTEM PAN AT CONTINUOUS I'i'-"-"

ACB LOW SPEED. ACC. TERM. ENERGIZED. I

Job Name

Job Location

City

Unit Model Number

Electrical Connections Tight? []

Blower MotorAJ'nps Blower Motor Horsepowedkw

Gas Piping Connections]3ght & Leaks Tested? []

Fuel Type: Natural Gas? [] LP/Propane Gas? []

Furnace Btu (kW) Input Une Pressure

Regulator Pressure w.c.IPa - Nat. w.c/Pa - LP/Pmpane

ConnectionsTight? [] ProperDraft? []

Fan Control Setting (45 Seconds Fixed On) Fan Control Off Setting

Temperature Rise FilterClean & Secure? []

START-UP AND PERFORMANCE CHECK LIST

Job Number Date

City State/province

State/province

Serial Number Service Technician

HEATING SECTION

Supply Voltage_

Vent Clear? []

Installer__

THERMOSTAT

Calibrated?[] HeatAnticipatorPropedySet? [] Level?D

Page 32