LENNOX Furnace/Heater, Gas Manual L0806183

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

Open the PDF directly: View PDF .
Page Count: 48

E Wvm)

,t,: 2005 Lennox industries inc.

Dallas, Texas, USA

RETAIN THESE INSTRUCTIONS

FOR FUTURE REFERENCE

INSTALLATION

INSTRUCTIONS

G51MP SERIES UNITS

GASU.iTS qT_bbTeoho,ca,

505,065M _L_ Publications

07/07

Supersedes 07/2005 Lithe U.S.A.

Unit Dimensions ............................... 2

G51MP Parts Identification ...................... 3

Shipping and Packing List ....................... 4

Safety Information .............................. 4

General ....................................... 6

Combustion, Dilution & Ventilation Air ............. 6

Installation - Setting Equipment .................. 8

Filters ........................................ 16

Duct System .................................. 16

Pipe & Fittings Specifications ................... 16

Vent Piping Guidelines ......................... 18

Joint Cementing Procedure ..................... 19

Venting Practices ............................. 19

Gas Piping ................................... 30

Electrical ..................................... 33

Unit Start-Up ................................. 37

Gas Pressure Adjustment ...................... 38

High Altitude Information ....................... 39

Other Unit Adjustments ........................ 40

Service ...................................... 41

Repair Parts List .............................. 43

Ignition Control Board Diagnostic Codes ......... 43

Troubleshooting ............................... 44

Vent Pipe Sizing Worksheet .................... 48

Start-Up & Performance Check List .............. 48

AWARNING

Do not store or use gasoline or other

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.

•Do not touch any electrical switch; do not

use any phone in your building.

•Leave the building immediately.

•Immediately call your gas supplier from a

neighbor's phone. Follow the gas supplier's

instructions.

•If you cannot reach your gas supplier, call

the fire department.

07/07

IIIlllllllllllllllllllllllllllllllllllll Page 1

505,065M

IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIBlllllllll

*NOTE - 60C and 60D size units installed in upflow applica-

tions that require air volumes over 1800 cfm (850 L/s) must

have one of the following:

1. Single side return air with transition, to accommodate

20 x 25 x 1 in. (508 x 635 x 25 mm) air filter.

Required to maintain proper air velocity.

2. Single side return air with optional RAB Return Air Base

3. Bottom return air.

4. Return air from both sides.

5. Bottom and one side return air.

Refer to Engineering Handbook for additional information.

**Consider sizing requirements for optional IAQ equipment

before cutting side return opening.

1 Optional External Side Return Air Filter Kit is not for use

with the optional RAB Return Air Base.

SUPPLY AIR

OPENING

_OPTIONAL /=_-

EXTERNAL 23-3/4 (803)

SIDE RETURN I.........

AIR FILTER KIT I_ za _o._a/ v

(Either Side) TOP VIEW

._ A -_

9v----- B -_

AIR FLOW

9-9/16 (14)

1OPTIONAL

EXTERNAL

SIDE RETURN

AIR FILTER KIT

(Either Side)

5/8(16)

314(19)

11-5/8

(295) Right

9-3/4 (248)

Left

(1016)

I_ 28 -1/2

I_ (724)

5-1/2 _._ _._1._ 19-7/16 ._1_

$r_ COMBUSTION AIR INTAKE

6-1/2 .... _ _ (Either Side)

( I )/ \ /EXHAUST AIR OUTLET

4-1/8 6-3/4 9- _/_ ._ (Either Side)

(103) (171) .. GASPIPINGINLET

_ll_._f\_._)_ (Either Side)

tJ \ .r_ CONDENSATE

L_TRAPCONNECTION

°Oo--___" (Either Side)

_ ELECTRICAL INLET

_p_.ql__ - (Either side )

04- --

I 23

{102 (584) I

"*OPTIONAL 14"*

I RETURN CUTOUT (356)

I (Either Side)

1-15/16 (49)

4-7/8 (124) Right

2-1/4 (57) Left -I_

A2-1/2 .__

(64)

18-3/4 (476)

Jl.--c 4-

3/4 (19) *Bottom Return 4-1/4 *Bottom Return

Air Opening (108) Air Opening

FRONT VIEW SIDE VIEW

9/16

'q'- (14)

A B C

Model No. in. mm in. mm in. mm

G51MP-24B-045

G51MP-36B-045 17-1/2 446 16-3/8 416 16 406

G51MP-36B-070

G51 MP-36C-090

G51MP-48C-090

G51MP-60C-090 21 533 19-7/8 454 19-1/2 495

G51MP-48C-110

G51MP-60C-110

G51MP-60D-135 24-1/2 622 23-3/8 546 23 584

Page 2

G51MP PARTS IDENTIFICATION

DuralokPlus TM

HEATEXCHANGER

ASSEMBLY

GAS VALVE

AND MANIFOLD

FLUE

COLLAR

COMBUSTION

AIR PRESSURE

PROVE SWITCHES

BURNER

ACCESS

PANEL

BLOWER

ACCESS

DOOR

SIGHT

GLASS

DOOR

INTERLOCK

SWITCH

CONTROL BOX

FIGURE 1

CABINET

WARM HEADER

(COLLECTOR)

BOX

CONDENSER COIL

PRIMARY LIMIT

,/_ COLD HEADER

(COLLECTOR)

/_ BOX

SECONDARY

LIMITS (2)

BLOWER

ASSEMBLY

Page 3

TheG51MPgasfurnaceisshippedreadyforinstallationin

theupflow,downflow,horizontalleftairdischargeorhori-

zontalrightairdischargeposition.Thefurnaceisshipped

withthebottompanelinplace.Thebottompanelmustbe

removedif theunitistobeinstalledinupflowapplications

withbottomreturnair.Thebottompanelmustalsobere-

movedanddiscardedinalldownfloworhorizontalapplica-

tions.

Thefurnaceisequippedforinstallationinnaturalgasap-

plications.A conversionkit(orderedseparately)isrequired

foruseinpropane/LPgasapplications.

The G51MP can be installed as either a Direct Vent or a

Non-Direct Vent gas central furnace.

NOTE -In Direct Vent installations, combustion air is taken

from outdoors and flue gases are discharged outdoors. In

Non-Direct Vent installations, combustion air is taken from

indoors and flue gases are discharged outdoors. See fig-

ure 2for applications involving roof termination.

NOTE -G51MP-48C-110 and G51MP-60C-110 units also

include a 2" diameter ABS street elbow, which is shipped

on the blower deck in the heating compartment.

G51MP-60D-135 units are shipped with a 3" to 2"ABS re-

ducing elbow.

The following items may also be ordered separately:

1- Thermostat

1 - Propane/LP changeover kit

Check equipment for shipping damage. If you find any

damage, immediately contact the last carrier.

&WARNING

DIRECT VENT INSTALLATION

COMBUSTION I EXHAUST

AIR iNTAKE r OUTLET

OUTSIDE OF

HOUS_

DRAIN

NON-DIRECT VENT

INSTALLATION

'EXHAUST

OUTLET

COMBUSTION

AiR iNTAKE INSIDE

OF HOUSE

FIGURE 2

CONDENSATE

DRAIN

Package 1 of 1 contains

1 - Assembled G51MP unit

1 - Bag assembly containing the following:

3 - Screws

3 -Wire nuts

1 - Snap bushing

1 - Snap plug

1 - Wire tie

1 - Condensate trap

1 - Condensate trap cap

2 -2" diameter vent /intake plugs

1 - 3" diameter cabinet plug (intake)

1 -2" diameter debris screen

&CAUTION

Use only the type of gas approved for use with this furnace.

Refer to unit nameplate.

G51MP units are CSA International certified to ANSI

Z21.47 and CSA 2.3 standards.

In the USA, installation of gas furnaces must conform with

local building codes. In the absence of local codes, units

must be installed according to the current National Fuel

Gas Code (ANSl-Z223.1/NFPA 54). The National Fuel

Gas Code is available from the following address:

American National Standards Institute, Inc.

11 West 42nd Street

New York, NY 10036

In Canada, installation must conform with current National

Standard of Canada CSA-B149 Natural Gas and Propane

Installation Codes, local plumbing or waste water codes

and other applicable local codes.

In order to ensure proper unit operation in non-direct vent

applications, combustion and ventilation air supply must be

provided according to the current National Fuel Gas Code

or CSA-B149 standard.

This furnace is CSA International certified for installation

clearances to combustible material as listed on the unit

nameplate and in the tables in figures 7, 12 and 16. Acces-

sibility and service clearances must take precedence over

fire protection clearances.

NOTE -For installation on combustible floors, the furnace

shall not be installed directly on carpeting, tile, or other

combustible material other than wood flooring.

Page 4

Forinstallationinaresidentialgarage,thefurnacemustbe

installedsothattheburner(s)andtheignitionsourceare

locatednolessthan18inches(457mm)abovethefloor.

Thefurnacemustbelocatedorprotectedtoavoidphysical

damagebyvehicles.Whenafurnaceisinstalledinapublic

garage,hangar,orotherbuildingthathasahazardousat-

mosphere,thefurnacemustbeinstalledaccordingtorec-

ommendedgoodpracticerequirementsandcurrentNa-

tionalFuelGasCodeorCSAB149standards.

NOTE -Furnace must be adjusted to obtain a temperature

rise within the range specified on the unit nameplate. Fail-

ure to do so may cause erratic limit operation and prema-

ture heat exchanger failure.

This G51MP furnace may be used as a high-static unit

heater. The G51MP may also be installed in an aircraft

hangar in accordance with the Standard for Aircraft Han-

gars (ANSI/NFPA No. 408-1990).

Installation in parking structures must be in accordance

with the Standard for Parking Structures (ANSI/NFPA No.

88A-1991 ). Installation in repair garages must be in accor-

dance with the Standard for Repair Garages (ANSI/NFPA

No. 88B-1991 ).

This G51MP furnace must be installed so that its electrical

components are protected from water.

When this furnace is used with cooling units, it shall be

installed in parallel with, or on the upstream side of, cooling

units to avoid condensation in the heating compartment.

With a parallel flow arrangement, a damper (or other

means to control the flow of air) must adequately prevent

chilled air from entering the furnace. If the damper is manu-

ally operated, 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, this furnace must be electrically grounded

according to local codes. In addition, in the United States,

installation must conform with the current National Electric

Code, ANSI/NFPA No. 70. The National Electric Code

(ANSl/NFPA No. 70) is available from the following ad-

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 codes.

NOTE -This furnace is designed for a minimum continuous

return air temperature of 60°F (16°C) or an intermittent op-

eration down to 55°F (13°C) dry bulb for cases where a

night setback thermostat is used. Return air temperature

must not exceed 85°F (29°C) dry bulb.

The G51MP furnace may be installed in alcoves, closets,

attics, basements, garages, and utility rooms.

This furnace design has not been CSA certified for installa-

tion in mobile homes, recreational vehicles, or outdoors.

Never use an open flame to test for gas leaks. Check all

connections using a commercially available soap solution

made specifically for leak detection.

Lennox does not recommend the use of G51MP units as a

construction heater during any phase of construction. Very

low return air temperatures, harmful vapors and operation

of the unit with clogged or misplaced filters will damage the

unit.

G51MP units may be used for heating of buildings or struc-

tures under construction, if the following conditions are

met:

•The vent system must be permanently installed per

these installation instructions.

• A room thermostat must control the furnace. The use of

fixed jumpers that will provide continuous heating is not

allowed.

• The return air duct must be provided and sealed to the

furnace.

• Return air temperature range between 60°F (16°C) and

80°F (27°C) must be maintained.

• Air filters must be installed in the system and must be

maintained during construction.

• Air filters must be replaced upon construction comple-

tion.

• The inputrate and temperature rise mustbe setperthe

furnace rating plate.

• One hundred percent (100%) outdoor air must be pro-

vided for combustion air requirements during construc-

tion. Temporary ducting may supply outdoor air to the

furnace. Do not connect duct directly to the furnace.

Size the temporary duct following these instructions in

section for Combustion, Dilution and Ventilation Air in a

confined space with air from outside.

• The furnace heat exchanger, components, duct sys-

tem, air filters and evaporator coils must be thoroughly

cleaned following final construction clean-up.

• All furnace operating conditions (including ignition, in-

put rate, temperature rise and venting) must be verified

according to these installation instructions.

NOTE -The Commonwealth of Massachusetts stipu-

lates these additional requirements:

•Gas furnaces shall be installed by a licensedplumb-

er or gas fitter only.

•The gas cock must be "T handle" type.

•When a furnace is installed in an attic, the passage-

way to and service area surrounding the equipment

shall be floored.

Page 5

Theseinstructionsareintendedasageneralguideanddo

notsupersedelocalcodesinanyway,Consultauthorities

havingjurisdictionbeforeinstallation.

Inadditiontotherequirementsoutlinedpreviously,thefol-

lowinggeneralrecommendationsmustbe considered

wheninstallinga G51MPfurnace:

• Placethefurnaceascloseto thecenterof theairdis-

tributionsystemaspossible.Thefurnaceshouldalsobe

locatedclosetothechimneyorventterminationpoint,

• Whenthefurnaceisinstalledinnon-directventapplica-

tions,donotinstallthefurnacewheredraftsmightblow

directlyintoit,Thiscouldcauseimpropercombustion

andunsafeoperation,

• Whenthefurnaceisinstalledinnon-directventapplica-

tions,donotblockthefurnacecombustionairopening

withclothing,boxes,doors,etc.Airisneededforproper

combustionandsafeunitoperation.

• Whenthefurnaceisinstalledinanatticor otherinsu-

latedspace,keepinsulationawayfromthefurnace,

• Whenthe furnaceis installedin an unconditioned

space,considerprovisionsrequiredtopreventfreezing

ofcondensatedrainsystem,

If the G51MP is installed as a Non-Direct Vent Furnace,

follow the guidelines in this section.

NOTE- In Non-Direct Vent installations, combustion air is

taken from indoors and flue gases are discharged out-

doors.

,& WARNING

,& CAUTION

-&WARNING

In the past, there was no problem in bringing in sufficient

outdoor air for combustion, Infiltration provided all the air

that was needed. In today's homes, tight construction prac-

tices make it necessary to bring in air from outside for com-

bustion, Take into account that exhaust fans, appliance

vents, chimneys, and fireplaces force additional air that

could be used for combustion out of the house, Unless out-

side air is brought into the house for combustion, negative

pressure (outside pressure is greater than inside pressure)

will build to the point that a downdraft can occur in the fur-

nace vent pipe or chimney, As a result, combustion gases

enter the living space creating a po-tentially dangerous sit-

uation,

In the absence of local codes concerning air for combus-

tion and ventilation, use the guidelines and procedures in

this section to install G51MP furnaces to ensure efficient

and safe operation. You must consider combustion air

needs and requirements for exhaust vents and gas piping.

A portion of this information has been reprinted with per-

mission from the National Fuel Gas Code (ANSI-

Page 6

Z223.1/NFPA54).Thisreprintedmaterialisnotthecom-

pleteandofficialpositionof theANSIonthereferenced

subject,whichisrepresentedonlybythestandardinitsen-

tirety.

InCanada,referto theCSAB149installationcodes.

,&CAUTION

All gas-fired appliances require air for the combustion pro-

cess. If sufficient combustion air is not available, the fur-

nace or other appliance will operate inefficiently and un-

safely. Enough air must be provided to meet the needs of

all fuel-burning appliances and appliances such as ex-

haust fans which force air out of the house. When fire-

places, exhaust fans, or clothes dryers are used at the

same time as the furnace, much more air is required to en-

sure proper combustion and to prevent a downdraft. Insuf-

ficient air causes incomplete combustion which can result

in carbon monoxide.

In addition to providing combustion air, fresh outdoor air di-

lutes contaminants in the indoor air. These contaminants

may include bleaches, adhesives, detergents, solvents

and other contaminants which can corrode furnace compo-

nents.

The requirements for providing air for combustion and ven-

tilation depend largely on whether the furnace is installed in

an unconfined or a confined space.

Unconfined Space

An unconfined space is an area such as a basement or

large equipment room with a volume greater than 50 cubic

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

bined input rating of all appliances installed in that space.

This space also includes adjacent rooms which are not

separated by a door. Though an area may appear to be un-

confined, it might be necessary to bring in outdoor air for

combustion if the structure does not provide enough air by

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

construction with weather stripping and caulking around

the windows and doors, follow the procedures in the air

from outside section.

Confined Space

A confined space is an area with a volume less than 50 cu-

bic feet (1.42 m3) per 1,000 Btu (.29 kW) per hour of the

com-bined input rating of all appliances installed in that

space. This definition includes furnace closets or small

equipment rooms.

When the furnace is installed so that supply ducts carry air

circulated by the furnace to areas outside the space con-

taining the furnace, the return airmust be handled by ducts

which are sealed to the furnace casing and which terminate

outside the space containing the furnace. This is especially

important when the furnace is mounted on a platform in a

confined space such as a closet or small equipment room.

Even a small leak around the base of the unit at the platform

or at the return air duct connection can cause a potentially

dangerous negative pressure condition. Air for combustion

and ventilation can be brought into the confined space ei-

ther from inside the building or from outside.

Air from Inside

If the confined space that houses the furnace adjoins a

space categorized as unconfined, air can be brought in by

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 (.29 kW) per hour of

total input rating of all gas-fired equipment in the confined

space. Each opening must be at least 100 square inches

(64516 mm2). One opening shall be within 12 inches (305

mm) of the top of the enclosure and one opening within 12

inches (305 mm) of the bottom. See figure 3.

EQUIPMENT IN CONFINED SPACE - ALL AIR FROM INSIDE

ROOF TERMINAl ED_1_ __,_

EXHAUST PIPE

= -\ OPENINGS

-- (To Adjacent

SIDE WALL _ Unconfined

ERMINATED EX-

UST PIPE (ALTER- i __pace)

ATE LOCATION) G51MP #

Ill

,, ,, ,, ......... , ,, ,,

I I I I°

NOTE -Each opening shall have a free area of at least one square

inch per 1,000 Btu (645mm 2 per .29kW) per hour of the total input

rating of all equipment in the enclosure, but not less than 100 square

inches (64516mm. 2).

FIGURE 3

Air from Outside

If air from outside is brought in for combustion and ventila-

tion, the confined space shall be provided with two perma-

nent openings. One opening shall be within 12" (305mm) of

the top of the enclosure and one within 12" (305mm) of the

bottom. These openings must communicate directly or by

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

communicate with the outdoors or indirectly through verti-

cal ducts. Each opening shall have a minimum free area of

1 square inch per 4,000 Btu (645mm 2 per 1.17kW) per hour

of total input rating of all equipment in the enclosure. When

communicating with the outdoors through horizontal ducts,

Page 7

eachopeningshallhavea minimumfreeareaof1square

inchper2,000Btu(645mm2per.59kW)pertotalinputrat-

ingofallequipmentintheenclosure(Seefigure4),

EQUIPMENT IN CONFINED SPACE - ALL AIR FROM OUTSIDE

(Inlet Air from Crawl Space and Outlet Air to Ventilated Attic)

VENTILATION LOU-

ROOF TERMINATED VERS

EXHAUST PIPE (Each end of attic)

OUTLET

AIR

SIDE WALL

TERMINATED

EXHAUSTPIPE

(ALTERNATE

LOCATION) INLET

VENTILATION

LOUVERS

(For unheated

crawl space)

NOTE-The inlet and outlet air openings shall each have a free area

of at least one square inch per 4,000 Btu (645mm 2per 1.17kW) per

hour of the total input rating of all equipment in the enclosure.

FIGURE 4

If air from outside is brought in for combustion and ventila-

tion, the confined space must have two permanent open-

ings, One opening shall be within 12 inches (305 mm) of the

top of the enclosure and one opening within 12 inches (305

mm) of the bottom. These openings must communicate di-

rectly or by ducts with the outdoors or spaces (crawl or at-

tic) that freely communicate with the outdoors or indirectly

through vertical ducts. Each opening shall have a minimum

free area of 1 square inch (645 mm 2) per 4,000 Btu (1,17

kW) per hour of total input rating of all equipment in the en-

closure. See figures 4 and 5. When communicating with

the outdoors through horizontal ducts, each opening shall

have a minimum free area of 1 square inch (645 mm2) per

2,000 Btu (.56 kW) per total input rating of all equipment in

the enclosure, See figure 6,

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

tional area as the free area of the openings to which they

connect. 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, grilles, or screens must

be considered. If the design and free area of protective cov-

ering is not known for calculating the size opening required,

it may be assumed that wood louvers will have 20 to 25 per-

cent free area and metal louvers and grilles will have 60 to

75 percent free area. Louvers and grilles must be fixed in

the open position or interlocked with the equipment so that

they are opened automatically during equipment opera-

tion,

EQUIPMENT IN CONFINED SPACE - ALL AIR FROM OUTSIDE

(All Air Through Ventilated Attic)

ROOF TERMINATED VENTILATION LOUVERS

EXHAUST PIPE (Each end of attic)

TERMINATED

EXHAUSTPtPE

(ALTERNATE

LOCATION)

INLET AIR

(Ends 12"above

bottom)

NOTE-The inlet and outlet air openings shall each have a free area of

at least one square inch per 4,000 Btu (645mm2per 1.17kW) per hour

of the total input rating of all equipment in the enclosure.

FIGURE 5

EQUIPMENT IN CONFINED SPACE -

ALL AIR FROM OUTSIDE

ROOF TERMINATED

EXHAUST PIPE

SIDE WALL

TERMINATED

EXHAUSTPIPE

(ALTERNATE

LOCATION)

NO TE-Each air duct opening shall have a free area of at least one

square inch per 2,000 Btu (645mm2per. 59kW) per hour of the total

input rating of all equipment in the enclosure. If the equipment room

is located against an outside wall and the air openings communi-

cate directly with the outdoors, each opening shall have a free area

of at least 1 square inch per 4, 000 Btu (645mm 2per 1.17kW) per

hour of the total input rating of all other equipment in the enclosure.

FIGURE 6

-&WARNING I

Page 8

Selecta locationthatallowsfor therequiredclearances

thatarelistedontheunitnameplate.Alsoconsidergas

supplyconnections,electricalsupply,ventconnection,

condensatetrapanddrainconnections,andinstallation

andserviceclearances[24inches(610mm)atunitfront].

The unit must be level from front to back and side to side.

NOTE -1/3 hp blower motors are equipped with four flex-

ible mounting legs, and 1/2 hp blower motors are equipped

with three flexible legs and one rigid leg. The rigid leg is

equipped with a shipping bolt and a flat white plastic wash-

er (rather than the rubber mounting grommet used with a

flexible mounting leg). The bolt and washer must be re-

moved before the furnace is placed into operation. Af-

ter the bolt and washer have been removed, the rigid leg

will not touch the blower housing.

Allow for clearances to combustible materials as indicated

on the unit nameplate. Minimum clearances for closet or al-

cove installations are shown in figures 7, 12 and 16.

WARNING

AWARNING

Upflow Applications

The G51MP gas furnace can be installed as shipped in the

upflow position. Refer to figure 7 for clearances.

Installation Clearances

Top

Left Side Right Side

Bottom (Floor)

............................................... T...............................................

Top/Plenum i1 in. (25 ram)

*Front iO

."................... ....................T..............................................

,,'.....................-.........................f...............................................I

Vent i O

Floor I O:_

*Front clearance in alcove installation must be 24 in. (610 ram).

Maintain a minimum of 24 in. (610 ram) for front service access.

tAllow proper clearances to accommodate condensate trap and

vent pipe installation.

! :_For installations on acombustible floor, do not install the fur-

inace directly on carpeting, tile or other combustible materials oth-

i er than wood flooring.

=================================================================================================

FIGURE 7

Return Air -- Upflow Units

Return air can be brought in through the bottom or either

side of the furnace installed in an upflow application. If the

furnace is installed on a platform with bottom return, make

an airtight seal between the bottom of the furnace and the

platform to ensure that the furnace operates properly and

safely. The furnace is equipped with a removable bottom

panel to facilitate installation,

Markings are provided on both sides of the furnace cabinet

for installations that require side return air. Cut the furnace

cabinet at the maximum dimensions shown on page 2,

NOTE -When air volumes over 1800 cfm (850 L/s) are

required with 60C or 60D models in an upflow applica-

tion, the following return air options are available:

1-Return air from single side with transition which will

accommodate 20 x 25 x I in. (508 x 635 x 25 ram) air filter.

(Required to maintain proper air velocity.) See figure 8.

2-Return air from single side with optional RAB Return

Air Base. See figure 10.

3-Return air from bottom.

4-Return air from both sides.

5-Return air from bottom and one side.

Page 9

Refer to Engineering Handbook for additional information.

G51MP applications which include side return air and

a condensate trap installed on the same side of the

cabinet require either a return air base or field-fabri-

cated transition to accommodate an optional IAQ ac-

cessory taller than 14.2".

Side Return Air

(with transition and filter)

20" X 25" X 1"

(508mm X635mm X 25mm)

Air Filter

Return

Air

Plenum

Removing the Bottom Panel

Remove the two screws that secure the bottom cap to the

furnace. Pivot the bottom cap down to release the bottom

panel, Once the bottom panel has been removed, reinstall

the bottom cap, See figure 9,

Removing the Bottom Panel

Screw

\./

Bottom

Bottom Cap

FIGURE 8FIGURE 9

Optional Return Air Base

©' -fL

-I_ 4 I123 (584)

(102)r 91"-- Overall 1 Minimu"-_

t14 I (Maximum) 11 (279) I

Maximun_

I1Unit side return air 16)

AIR FLOW Opening |

.................................................................................. FURNACE J, __ __i

FRONT L

5-5/8 SIDE RETURN

7-1/4 (184) t143_ AiR OPENINGS

""(Either Side)

_ _ OPTIONAL RAB ql_ 23 (584) _

17-1/2 (446) RAB-B (98M60) RETURN AiR BASE

21 (533) RAB-C (98M58) 7/8 -I_ _1-- 27-5/8 (702)

24-1/2 (622) RAB-D (98M59) (22) SIDE VIEW

FRONT VIEW

NOTE- Optional Side Return Air Filter Kits are not for use with RAB Return Air Base.

1 Both the unit return air opening and the base return air opening must be covered by a single plenum or IAQ cabinet.

Minimum unit side return air opening dimensions for units requiring 1800 cfm or more of air (W x H): 23 x 11 in.

(584 x 279 mm).

The opening can be cut as needed to accommodate plenum or IAQ cabinet while maintaining dimensions shown.

Side return air openings must be cut in the field. There are cutting guides stenciled on the cabinet for the side return

air opening. The size of the opening must not extend beyond the markings on the furnace cabinet..

2 To minimize pressure drop, the largest opening height possible (up to 14 inches) is preferred.

NOTE- Optional Side Return Air Filter Kits are not for use with RAB Return Air Base.

122-7-16

(570)

Overall

Maximum)

_3/4

(19)

FIGURE 10

Page 10

Levelingan Upflow Unit

When the side return air inlets are used in an upflow ap-

plication, it may be necessary to install leveling bolts on the

bottom of the furnace. Use field-supplied corrosion-resist-

ant 5/16 inch machine bolts (4) and nuts (8). See figure 11.

NOTE -The maximum length of the bolt is 1-1/2 inches.

1 - Lie the furnace on its back and drill a 5/16 inch diame-

ter hole in each corner of the furnace's bottom. See fig-

ure 11 for the correct location of the holes. Drill through

the bottom panel and the bottom flange of the cabinet.

2 - Install one bolt and two nuts into each hole. Screw the

first nut onto a bolt and then insert the bolt into a hole. A

flat washer may be added between the nut and the bot-

tom of the unit.

3 - Screw another nut onto the bolt on the inside of the fur-

nace base. A flat washer may be added between the

nut and the bottom of the unit.

4 - Adjust the outside nut to the appropriate height and

tighten the inside nut to secure the arrangement.

NOTE -The unit may be tilted back-to-front a maximum of

1". This will ensure proper draining of the heat exchanger.

Leveling Bolt Installation

Inches (mm)

3/8

Furnace Front _¢

3/8 1-3/4

(44)

1-3/4

(44)

Leveling Bolt

Furnace

Bottom

Leveling Bolt

Locations

3/8

(1o)

3/8 1-3/4

(10) (44)

I-3/4 (44)

FIGURE 11

Downflow Applications

The unit may be installed three ways in downflow applica-

tions: on non-combustible flooring, on combustible flooring

using an additive base, or on a reverse-flow cooling cabi-

net. Do not drag the unit across the floor in the down-

flow position. Flange damage will result.

Refer to figure 12 for clearances in downflow applica-

tions.

•............................................................................................... q

Downflow Application Installation Clearances

Left Side

Top

Right Side

Bottom

&,I

............................................... T...............................................

Top i O

*Front IO

."................... ....................T..............................................

Sides i Ot

]

Vent i O

............................................... t ................................................

Floor i NC_:

*Front clearance in alcove installation must be 24 in. (616 ram).

Maintain a minimum of 24 in. (610 ram) for front service access.

tAllow proper clearances to accommodate condensate trap and

vent pipe installation.

_:The furnace may be installed on a combustible wood floor if an

i optional additive base is installed between the furnace and the

i combustible floor.

=================================================================================================

FIGURE 12

Installation on Non-Combustible Flooring

1 - Cut floor opening keeping in mind clearances listed on

unit rating plate. Also keep in mind gas supply connec-

tions, electrical supply, flue and air intake connections

and sufficient installation and servicing clearances.

See table 1 for correct floor opening size.

2 - Flange warm air plenum and lower the plenum into the

opening.

3 - Set the unit over the plenum and seal the plenum to

the unit.

3 - Ensure that the seal is adequate.

TABLE 1

NON-COMBUSTIBLE FLOOR OPENING SIZE

i............................[...... 'ronno' e;r"......[...... ........i

iModel No. _................................. _.................................

iii i•

i"i i "i •

I In. I mm I In. I mm I

iii i•

I, ,! ,I -I., I.

jBCabinet(17.5") i19-3/4, ,i 502 ,i 16-5/8 ,i 422 j

I, ,! ,I -I., I.

jCCabinet(21") ,i 19-3/4 ,i 502 ,i 20-1/8 ,i 511 j

I, ,! ,I -I., I.

•."-

• DCabmet(245) , 19 3/4 , 502 , 23 5/8 , 600 •

i............................[................L................[................[................i

NOTE -Floor opening dimensions listed are 1/4 inch (6 mm) larger than

the unit opening. See dimension drawing on page 2.

Page 11

Installation on Combustible Flooring

1 - When unit is installed on a combustible floor, an addi-

tive base must be installed between the furnace and

the floor. The base must be ordered separately for the

following cabinet sizes:

• B cabinet 17,5" - # 11M60

• C cabinet21"-# 11M61

• D cabinet 24,5" - # 11M62

See table 2 for opening size to cut in floor.

Ak CAUTION

TABLE 2

ADDITIVE BASE FLOOR OPENING SIZE

Model am

B Cabinet (17.5") 476

C Cabinet (21") 578

D Cabinet (24.5") 654

Frontto Rear

in. mm

22 559

Side to Side

in.

18 - 3/4

22 - 3/4

25 - 3/4

2 - After opening is cut, set additive base into opening.

3 - Check fiberglass strips on additive base to make sure

they are properly glued and positioned,

4 - Lower supply air plenum into additive base until ple-

num flanges seal against fiberglass strips.

NOTE -Be careful not to damage fiberglass strips,

Check for a tight seal,

5 - Set the furnace over the plenum.

6 - Ensure that the seal between the furnace and plenum

is adequate.

G51MP UNIT_ __T

SUPPLY AIR PLENUM

PROPERLY ,VEBASE

FIGURE 13

Installation on Cooling Cabinet

1 - Refer to reverse-flow coil installation instructions for

correctly sized opening in floor and installation of cabi-

net,

2 - When cooling cabinet is in place, set and secure the

furnace according to the instructions that are provided

with the cooling coil, Secure the furnace to the cabinet,

3 - Seal the cabinet and check for air leaks.

Return Air Opening -- Downflow Units

The following steps should be taken when installing ple-

num:

1-Bottom edge of plenum should be flanged with a

hemmed edge (See figure 14 or 15).

2 - Sealing strips should be used to ensure an airtight seal

between the cabinet and the plenum.

PLENUM ---,,_ _11 '''_

(Field Provided) _ SECURE FROM

•_UTSIDE CABINET

v II _ CABINET

SEAL,NGSTR, IlJ S,DEPANEL

(Field Provided) ...... II

Side View II

FIGURE 14

PLENUM _'_

(Field Provided_-..h.

SECURE FROM

INSIDE CABINET Side View

SEALING STRIP

,_Field Provided)

jCABINET

, SIDE PANEL

FIGURE 15

3 - In all cases, plenum should be secured to top of fur-

nace using sheet metal screws,

4 - Make certain that an adequate seal is made.

Page 12

Horizontal Applications

The G51MP furnace can be installed in horizontal applica-

tions with either right- or left-hand air discharge.

Refer to figure 16 for clearances in horizontal applications,

H===================mmmmmmHHHmmmmmmHHHmmmmmmHHHmmmmmmHHHm.

Horizontal Application

Installation Clearances

Right-Hand Discharge

Top

Left

End Right End

Left-Hand Discharge

Top

Left

End Right End

Top ] O

i................... ron;:...................i.............................................i

Back 1O

".................... ....................i"..............................................

Vent !o

...................." oor"...................T.....................;;.......................

| ............................................... _ ................................................

*Front clearance in alcove installation must be 24 in. (610 ram).

Maintain a minimum of 24 in. (610 ram) for front service access.

**A 5-1/2" service clearance must be maintained below the unit to

provide for servicing of the condensate trap.

_:For installations on a combustible floor, do not install the fur-

nace directly on carpeting, tile or other combustible materials oth-

er than wood flooring.

FIGURE 16

This furnace may be installed in either an attic or a crawl-

space. The G51MP may also be installed as a unit heater.

Either suspend the furnace from roof rafters or floor joists,

as shown in figure 17, or install the furnace on a platform,

as shown in figure 18. The unit must be supported at both

ends and beneath the blower deck to prevent sagging,

NOTE -In horizontal applications, the unit must be lev-

el side to side. The unit may be tilted back to front a maxi-

mum of 1': This willensure proper draining of the heat ex-

changer.

Installation of Horizontal Furnace

Suspended in Attic

NOTE -If unit is suspended in attic or crawl space, horizon-

tal support kit (Cat No 56J18 ordered separately) must be

used to ensure proper unit support and coil drainage.

1 - Select location for unit keeping in mind service and

other necessary clearances, See figure 16.

2 - Provide service platform in front of unit,

3 - Fabricate a drain pan fitted with a 1/2 inch or 3/4 inch

N,P,T, fitting.

4- Using 3/8 inch rods and support frame kit (ordered

separately), fabricate suspension hangers for unit

keeping in mind front service access clearances.

5 - Mount unit on support frame as shown in figure 17.

Unit must be level to ensure proper coil drainage,

6- Continue with exhaust, condensate and intake line

piping instructions,

BLOWER ACCESS PAN- 3/8 in. RODS

INTAKE/EXHAUST EL

CONNECTION

DRAIN PAN

SUPPORT FRAME (to protect finished space)

FIGURE 17

7 - Hang drain pan below support frame as shown in fig-

ure 17. Leave 5-1/2 inches for service clearance be-

low unit for condensate trap,

8 - Route auxiliary drain line so that water draining from

this outlet will be easily noticed by the homeowner,

Platform Installation of Horizontal Unit in Attic

1 - Select location for unit keeping in mind service and

other necessary clearances. See figure 16,

2 - Construct a raised wooden frame and cover frame

with a plywood sheet, Provide a service platform and

drain pan for unit,

Page 13

TYPICAL HORIZONTAL APPLICATION (FORCED AIR FURNACE)

WASHER AND 2 NUTS

BRACED FOR

SUPPORT

INTAKE \Xx\

EXHAUST

PIPE

LAG BOLT

SUPPORT ROD

*Gas connector may be used for Canadian

installation if acceptable by the local author-

ity that has jurisdiction.

NOTE -Condensate trap and condensate line

must be protected by self-regulating heating

cable and insulation when run through un-

conditioned spaces.

DRAIN PAN

(to protect ............

finished

space)

/SUPPORT

FRAME

INTAKE

*Gas connector ma

used for Canadian

installation ff accept-

able by local authority

having judsdJction.

FIGURE 18

EXHAUST PIPE

*GAS

CONNECTOR

RAISED

CONDENSATE

LINE SERVICE PLATFORM

FIGURE 19

3 - Route auxiliary drain line so that water draining from

this outlet will be easily noticed by the homeowner.

4 - Set unit in drain pan as shown in figure 19. Unit must

be level to ensure proper coil drainage, Leave 5-1/2

inches for service clearance below unit for condensate

trap,

5 - Continue with exhaust, condensate and intake piping

installation according to instructions.

Installation of Horizontal Unit

Suspended in Crawl Space

NOTE -If unit is suspended in attic or crawl space, support

frame kit (Cat No 56J18 ordered separately) must be used

to ensure proper unit support and coil drainage.

1 - Select location for unit keeping in mind service and

other clearances, See figure 16,

BLOWER ACCESS

PANEL

2 - Using 3/8 inch rods and support frame kit, fabricate

suspension hangers keeping in mind service access

panel clearances,

3 - Install unit on support frame as shown in figure 20. Unit

must be level to ensure proper coil drainage, Leave

5-1/2 inches for service clearance below unit for con-

densate trap.

INTAKE

PIPE SUPPORT

FRAME

FIGURE 20

4 - Install exhaust and intake piping according to instruc-

tions given in following section. Condensate line

should be run into condensate pump if necessary to

meet drain line slope requirements.

Platform Installation of Horizontal

Unit in Crawl Space

1 - Select location for unit, keeping in mind service and

other clearances,

2 - After positioning cement blocks, mount support frame

kit (Cat No 56J18 ordered separately) on top of blocks

and install unit on frame. Unit must be level to ensure

proper heat exchanger coil drainage. Leave 5-1/2

inches for service clearance) for condensate trap,

Page 14

INTAKE

PIPE

EVAPORATOR COIL

FIGURE 21

3 - Install exhaust and intake piping according to informa-

tion given in following section. Condensate line should

be run into condensate pump as shown in figure 21,

G51MP Installed in Unit Heater Applications

Horizontal unit heaters may be installed either suspended

from the ceiling using the support frame kit or mounted on a

field-fabricated platform. The condensate trap must be

installed where it can be serviced at a later date,

Unit Heater Discharge Duct Guidelines

A field-fabricated and installed discharge air duct and grille

cabinet is suitable for use with the G51MP heater, See fig-

ure 22. Keep the following items in mind when constructing

the cabinet.

1 - Outer dimensions of cabinet should match those of the

unit heater, so the duct/grille cabinet installs flush with

the unit heater cabinet. See figure 22.

2 - Flange both ends of duct/grille cabinet so that screws

can be used to secure cabinet to discharge end of unit

heater.

DISCHARGE AIR DUCT/GRILLE CABINET

18in. (457 mm) Ik _"

FIELD-FABRICATE GRILL CABINET

TO DESIRED DIMENSION

FIGURE 22

3- To ensure proper operation, the duct/grille cabinet

must be at least 18 inches long,

4 - Use #10-16 x 1/2 inch sheet metal screws to secure

duct/grille cabinet to unit, taking care not to damage in-

ternal components of unit heater when drilling holes or

installing screws. See figure 23,

5 - Use adjustable, double-deflection grille(s) to distribute

discharge air. Adjust static pressure to be in the 0,06

inch to 0,10 inch w,c, range,

DRAIN PAN

(to protect '_

finished

space)

NOTE -When installing duct/grille cabinet, take care not to damage internal unit

heater components when dnlhng holes or installing screws.

FIGURE 23

Installation of Horizontal Unit Heater

Suspended from Ceiling

1 - Select location for unit keeping in mind service and

other clearances.

2 - Fabricate a drain pan fitted with 1/2 inch (13 mm) or

3/4 inch (19 mm) N.P.T. fitting.

3 - Using 3/8 inch (9 mm) rods and support frame kit (or-

dered separately), fabricate suspension hangers,

keeping in mind service access panel clearances.

4 - Hang drain pan below support frame as shown in fig-

ure 23, Route auxiliary drain line so that water drain-

ing from this outlet will be easily noticed by the home-

owner,

5 - Mount unit on support frame as shown in figure 23.

Unit must be level to ensure proper coil drainage.

Leave 5-1/2 inches for service clearance below unit for

condensate trap,

6- Continue with exhaust, condensate and intake line

piping instructions.

Platform Installation of Horizontal Unit Heater

1 - Select location for unit keeping in mind service and

other necessary clearances.

2 - Construct a raised wooden frame and cover frame

with a plywood sheet. Provide service platform and

drain pan for unit, Route auxiliary drain line so that wa-

ter draining from this outlet will be easily noticed by the

homeowner,

3 - Set unit in drain pan as shown in figure 24, Unit must

be level to ensure proper coil drainage, Leave 5-1/2

inches for service clearance below unit for condensate

trap.

4 - Continue with exhaust, condensate and intake piping

installation according to instructions which follow.

Page 15

INTAKE

PIPE

*GAS CONNECTOR

*Gas connector may be

used for Canadian instal-

lation ff acceptable by b-

ca/authority having juns-

diction.

RAISE

CONDENSATE LINE PLATFORM

FIGURE 24

Return Air -- Horizontal Applications

Return air can be brought in through the end of a furnace

installed in a horizontal application. The furnace is

equipped with a removable bottom panel to facilitate instal-

lation, See figure 9.

This unit is not equipped with a filter or rack, A field-pro-

vided filter is required for the unit to operate properly, Table

3 lists recommended filter sizes,

A filter must be in place whenever the unit is operating,

TABLE 3

Furnace

Cabinet Size

17-1/2"

21"

24-1/2"

Filter Size

Side Return Bottom Return

16X25X 1(1) 16X25Xl(1)

16X25X 1(1) 20X25Xl(1)

16X25X 1(2) 24X25Xl(1)

Use industry-approved standards to size and install the

supply and return air duct system. This will result in a quiet

and low-static system that has uniform air distribution.

NOTE - Operation of this furnace in heating mode (indoor

blower operating at selected heating speed) with an exter-

nal static pressure which exceeds 0.5 inches w.c. may re-

sult in erratic limit operation.

Supply Air Plenum

If the furnace is installed without a cooling coil, a removable

access panel should be installed in the supply air duct, The

access panel should be large enough to permit inspection

(by reflected light) of the heat exchanger for leaks after the

furnace is installed, The furnace access panel must always

be in place when the furnace is operating and it must not

allow leaks into the supply air duct system,

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 appliance

is operating in a room with negative pressure, the flue prod-

ucts can be pulled back down the vent pipe and into the

room, This reverse flow of the flue gas may result in incom-

plete combustion and the formation of carbon monoxide

gas. This toxic gas might then be distributed throughout the

house by the furnace duct system.

Return air can be brought in through the bottom or either

side of the furnace, If a furnace with bottom return air is

installed on a platform, make an airtight seal between the

bottom of the furnace and the platform to ensure that the

unit operates properly and safely. Use fiberglass sealing

strips, caulking, or equivalent sealing method between the

plenum and the furnace cabinet to ensure a tight seal. If a

filter is installed, size the return air duct to fit the filter frame.

All pipe, fittings, primer and solvent cement must conform

with American National Standard Institute and the Ameri-

can Society for Testing and Materials (ANSI/ASTM) stan-

dards. The solvent shall be free flowing and contain no

lumps, undissolved particles or any foreign matter that ad-

versely affects the joint strength or chemical resistance of

the cement. The cement shall show no gelation, stratifica-

tion, or separation that cannot be removed by stirring. Re-

fer to the table 4 below for approved piping and fitting mate-

rials.

TABLE 4

PIPING AND FITTINGS SPECIFICATIONS

ASTM

PIPE & FITTING MATERIAL SPECIFICATION

Schedule 40 PVC (Pipe) D1785

Schedule 40 PVC (Cellular Core Pipe) F891

Schedule 40 PVC (Fittings) D2466

SDR-21PVC (Pipe) D2241

SDR-26 PVC (Pipe) D2241

Schedule 40 ABS Cellular Core DWV (Pipe) F628

Schedule 40 ABS (Pipe) D1527

Schedule 40 ABS (Fittings) D2468

ABS-DWV (Drain Waste & Vent) D2661

(Pipe & Fittings)

PVC-DWV (Drain Waste & Vent) D2665

Pipe & Fittings)

Ak CAUTION

Page 16

Primersand solventsmustmeetASTMspecifications.

PVCprimerisspecifiedinASTMF656.UsePVCsolvent

cementasspecifiedinASTMD2564andABSsolventce-

mentasspecifiedinASTMD2235.Lowtemperaturesol-

ventcementis recommended.Metalorplasticstrapping

maybeusedforventpipehangers,

WhenmakingABSjoints,piecescanbepreparedwitha

cleaner.WhenjoiningABStoPVCmaterials,usePVCsol-

ventcement,Referto the procedurespecifiedinASTM

D3138,

Canadian Applications Only -Pipe, fittings, primer and sol-

TABLE 5

OUTDOOR TERMINATION KITS AND CORRESPONDING EQUlVALENClES

Vent Pipe Length Equivalency (feet)

Outdoor

VENT Exhaust

UNIT PIPE Accelerator

MODEL DIA. (Dia. X

(in.) Length)

Outdoor

Exhaust

Accelera-

tor

(Dia. X

Length)

1-1/2"

Concen-

tric Kit

2" Con-

centric

Kit

vent cement used to vent this appliance must be certified to

ULC $636 and supplied by a single manufacturer as part of

an approved venting system. When bonding the vent sys-

tem to the furnace, use ULC $636 approved One-Step

Transition Cement to bond the pipe to the flue collar, 90°

elbow or reducing 90 °elbow as applicable. In addition, the

first three feet of vent pipe from the furnace flue collar must

be accessible for inspection.

Table 5 lists the available exhaust termination kits, as well

as vent pipe equivalencies which must be used when sizing

vent pipe. All Lennox vent terminations are PVC or ABS.

2" Wall

Plate Kit

3" Wall

Plate Kit

3" Con-

centric

Kit

2" Wall

Kit with

Vent Ex-

tension

2" Wall

Ring Kit

22G44 44J40

1-1/2" X 12" 2" X 12" 71M80 69M29 60L46 30G28 81J20 30G79 15F74

2 4 Not 12 Not Not 4 4* 4 4

Allowed Allowed Allowed

2-1/2 5 Not 15 Not Not 5 5* 5 5

24B-045 Allowed Allowed Allowed

36B-045 3 7 Not 21 Not Not 7 7* 7 7

Allowed Allowed Allowed

4 14 Not 42 Not Not 14 14" 14 14

Allowed Allowed Allowed

2 4 Not 12 Not Not 4 4* 4 4

Allowed Allowed Allowed

2-1/2 5 Not 15 Not Not 5 5* 5 5

Allowed Allowed Allowed

36B-070

3 8 Not 24 Not Not 8 8* 8 8

Allowed Allowed Allowed

4 14 Not 42 Not Not 14 14" 14 14

Allowed Allowed Allowed

2 Not 1 Not 3 3 Not 1 Not 1**