Lennox G61MPV Series User manual

EJwvox )
®
_ 2006 Lennox Industries Inc.
Dallas, Texas, USA
INSTALLATION
INSTRUCTIONS
G61MPV SERIES UNITS
GAS UNITS Technical
505,240M J LJ _.Publications
07/2007 ......
Supersedes 10/2006 Lithe U.S.A.
RETAIN THESE INSTRUCTIONS
FOR FUTURE REFERENCE
Unit Dimensions ............................... 2
G61MPV Parts Arrangement ..................... 3
Shipping and Packing List ....................... 4
Safety Information .............................. 4
General ....................................... 6
Combustion, Dilution & Ventilation Air ............. 6
Installation - Setting Equipment .................. 9
Filters ........................................ 16
Duct System .................................. 17
Pipe & Fittings Specifications ................... 17
Vent Piping Guidelines ......................... 19
Joint Cementing Procedure ..................... 20
Venting Practices ............................. 21
Gas Piping ................................... 32
Electrical ..................................... 34
Integrated Control Board ....................... 41
Unit Start-Up ................................. 51
Gas Pressure Adjustment ...................... 52
High Altitude Information ....................... 53
Other Unit Adjustments ........................ 55
Service ...................................... 56
Ignition Control Board Diagnostic Codes ......... 57
Troubleshooting ............................... 58
Repair Parts List .............................. 66
Vent Pipe Sizing Worksheet .................... 66
Start-Up & Performance Check List .............. 67
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
IIIH]ININIIIIIIIIIIIIII]IIII]IIIIIIII Page 1 505,240M IIHIIIII]IIIIIIIIIIIII]III]IIIIIIIIIIIIIIIIII

"60C and 60D size units installed in upflow applications
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 equip-
ment before cutting side return opening.
1Optional External Side Return Air Filter Kit is not for use
with the optional RAB Return Air Base.
,,_ A-_
B-_ _-9/16(14)
t
AIR FLOW
_OPTIONAL
EXTERNAL
SIDE RETURN
AIR FILTER KIT
(Either Side)
SUPPLY AIR
OPENING
t6-1/2
11-5/8(1 5)
(295) Right
23-3/4 (603)
i_-_ 25 (635)
TOP VIEW
28-1/2
I_ (724)
5-1/2 _ _.,91._ 19-7/16 ._1_
$r_ COMBUSTION AIR INTAKE
.... _ _ (Either Side)
( ly \ /EXHAUST AIR OUTLET
9- _/_ /_ (Either Side)
GASP,P,NG,NLET
_11_/_f\ (Either Side)
\.r_ CONDENSATE
L_TRAPCONNECTION
°Oo_ (Either Side)
_ ELECTRICAL INLET
, ,Ei, er i ei
164) ....
I23
1OPTIONAL
EXTERNAL
SIDE RETURN
AIR FILTER KIT
(Either Side) ,o
(1016)
'_' 5/8 (16)
--J_l- 3/4 (19)
9-3/4 (248) 4-1/8 6-3/4
Left (103) (171)
4-7/8 (124) Right
2-1/4 (57) Left -I_
18-3/4 (476) -I_ { 1_2_1_A (584) I
I*OPTIONAL 14"*
I RETURN CUTOUT
I(Either Side)
L1-15/16 (49)
Jl---c ---1-
3/4 (19) *Bottom Return 4-1/4 *Bottom Return
Air Opening (108) Air Opening
FRONT VIEW SIDE VIEW
9/16
91-(14)
A B C
Model No. in. mm in. mm in. mm
G61MPV-36B-045
G61MPV-36B-070 17-1/2 446 16-3/8 416 16 406
G61MPV-36B-071
G61MPV-36C-090
G61MPV-60C-090
G61MPV-60C-091 21 533 19-7/8 454 19-1/2 495
G61MPV-60C-110
G61MPV-60C-111
G61MPV-60D-135 24-1/2 622 23-3/8 546 23 584
Page 2

BURNER BOXASSEMBLY
*G61MPV-36B-045
units are equipped
with two switches.
GAS VALVE
AND MANIFOLD
FLUE
COLLAR
DuralokPlus TM
HEATEXCHANGER
ASSEMBLY
CABINET
COMBUSTION
AIR PRESSURE
PROVE SWITCHES* WARM HEADER
(COLLECTOR)
BOX
INDUCER
BURNER
ACCESS
PANEL
BLOWER
I ACCESS
SIGHT
GLASS
CIRCUIT
BREAKER
TRANSFORMER
\
Two-Stage, Variable Speed
Integrated Control Board
CONDENSER COIL
PRIMARY LIMIT
\
SECONDARY
LIMITS (2)
POWER CHOKE
(5 Ton Only)
DOOR
INTERLOCK
SWITCH
BLOWER MOTOR
FIGURE 1
Page 3

TheG61MPVgasfurnaceisequippedwithatwo-stage,
variablespeedintegratedcontrol.Thiscontrolensures
compatibilitywithLennox'HarmonyIIIzonecontrolsys-
tem,aswellasathermostatwhichprovideshumiditycon-
trol.EachG61MPVisshippedreadyforinstallationinthe
upfiow,downflow,horizontalleftairdischargeorhorizontal
rightairdischargeposition.Thefurnaceisshippedwiththe
bottompanelinplace.Thebottompanelmustberemoved
iftheunitistobeinstalledinupflowapplicationswithbot-
tomreturnair.Thebottompanelmustalsoberemovedand
discardedinalldownfioworhorizontalapplications.
Thefurnaceisequippedforinstallationinnaturalgasap-
plications.Aconversionkit(orderedseparately)isrequired
foruseinpropane/LPgasapplications.
The G61MPV 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 2 for appfications involving roof termination.
DIRECT VENT INSTALLATION
COMBUSTION EXHAUST
AIR INTAKE OUTLET
OUTSIDE OF
HOUSE _
CONDENSATE
DRAIN"_
I
FIGURE 2
NON-DIRECT VENT
INSTALLATION
EXHAUST
OUTLET
COMBUSTION
AIR INTAKE INSIDE
OF HOUSE
CONDENSATE
DRAIN
Package 1 of 1 contains
1 - Assembled G61MPV 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
1 -Logo sticker (for use in downfiow applications)
NOTE -G61MPV-60C-110 and-111 units also include a 2"
diameter ABS street elbow, which is shipped on the blower
deck in the heating compartment. G61MPV-60D-135 units
are shipped with a 3" to 2" ABS reducing 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
a,CAUTION
Use only the type of gas approved for use with this furnace.
Refer to unit nameplate.
G61MPV 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 (ANSI-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-
tionalFuelGasCodeorCSAB149standard.
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.
This G61MPV furnace may be used as a high-static unit
heater. The G61MPV may also be installed in an aircraft
hangar in accordance with the Standard for Aircraft Han-
gars (ANSl/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 G61MPV furnace must be installed so that its electri-
cal 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
(ANSI/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 G61MPV 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 G61MPV units as
a construction heater during any phase of construction.
Very low return air temperatures, harmful vapors and op-
eration of the unit with clogged or misplaced filters will dam-
age the unit.
G61MPV units may be used for heating of buildings or
structures 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 input rate and temperature rise must be set per the
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
wheninstallingaG61MPVfurnace:
• Placethefurnaceasclosetothecenteroftheairdis-
tributionsystemaspossibleThefurnaceshouldalsobe
locatedclosetothechimneyorventterminationpoint
• Whenthefurnaceisinstalledinnon-directventapplica-
tions,donotinstallthefurnacewheredraftsmightblow
directlyintoit Thiscouldcauseimpropercombustion
andunsafeoperation
• Whenthefurnaceisinstalledinnon-directventapplica-
tions,donotblockthefurnacecombustionairopening
withclothing,boxes,doors,etcAirisneededforproper
combustionandsafeunitoperation
• Whenthefurnaceisinstalledinanatticor otherinsu-
latedspace,keepinsulationawayfromthefurnace
• Whenthefurnaceis installedin an unconditioned
space,considerprovisionsrequiredtopreventfreezing
ofcondensatedrainsystem
,CAUTION
WARNING
If the G61MPV is installed as a Non-Direct Vent Fur-
nace, 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
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 potentially dangerous situ-
ation.
In the absence of local codes concerning air for combus-
tion and ventilation, use the guidelines and procedures in
this section to install G61MPV 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-
Z223 1/NFPA 54) This reprinted material is not the com-
plete and official position of the ANSI on the referenced
subject, which is represented only by the standard in its en-
tirety
In Canada, refer to the standard CSA B149 installation
codes
Page 6

ACAUTION
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 air must 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 TERMINA] ED_lr
EXHAUST PIPE
'-, _ OPENINGS
•-- (To Adjacent
SIDE WALL _1 Unconfined
ERMINATED EX=
UST PIPE (ALTER- -- __pace)
ATE LOCATION) 361MPV /(
III
I I I I I I I I I I I I I I I I I I
' h ¢"l ¢'
NOTE -Each opening shall havo a free area of at least ono square
inch per 1,000 Btu (645mm 2per .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) dthe
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,
each opening shall have a minimum free area of 1 square
inch per 2,000 Btu (645mm 2 per .59kW) per total input rat-
ing of all equipment in the enclosure (See figure 4).
Page 7

EQUIPMENT IN CONFINED SPACE - ALL AIR FROM OUTSIDE
(Inlet Air from Crawl Space and Outlet Air to Ventilated Attic)
ROOF TERMINATED
EXHAUST PIPE
VENTILATION LOUVERS
(Each end of attic)
\ II I
OUTLET
AIR
IINATED
JST PIPE VENTIL
LOU_.
(":RNATE _6I MP_ INLET (For un
ATION) AIR %IL." crawl .'pace)
/
I_1 I" rrrm
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 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 aminimum 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)
7
ROOF TERMINATED VENTILATION LOUVERS
EXHAUST PIPE (Each end of attic)
TERMINATED
EXHAUSTPIPE
(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
EXHAUSTPtPE
(ALTERNATE
LOCATION)
NO TE-Each air duct opening shaft 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, ff the equipment room
is located against an outside wall and the air openings communi-
cate directly with the outdoors, each opening shaft 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 aft other equipment in the enclosure.
FIGURE 6
Page 8

&WARNING
Select a location that allows for the required clearances
that are listed on the unit nameplate. Also consider gas
supply connections, electrical supply, vent connection,
condensate trap and drain connections, and installation
and service clearances [24 inches (610 mm) at unit front].
The unit must be level from front to back and side to side.
NOTE -G61MPV-36B and -36C units with 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 washer (rather than the rubber mounting
grommet used with a flexible mounting leg). The bolt and
washer must be removed before the furnace is placed
into operation. After the bolt and washer have been re-
moved, the rigid leg will not touch the blower housing.
NQ TE -G61MPV-60D-135 units are equipped with a ship-
ping pad under the blower housing. Remove the shipping
pad prior to operation.
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
WARN ING
Upflow Applications
The G61MPV gas furnace can be installed as shipped in
the upflow position. Refer to figure 7 for clearances.
Installation Clearances
Top
Left Side Right Side
;q
Bottom (Floor)
............................................... T...............................................
Top/Plenum i 1 in. (25 ram)
*Front IO
."................... ..................................................................
Sides i 01-
t
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 a combustible floor, do not install the fur-
inace directly on carpeting, tile or other combustible materials oth-
ier 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 upfiow 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 transfion which will
accommodate 20 x25 x I in. (508 x635 x25 mm) 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.
Refer to Engineering Handbook for additional information.
Page 9

G61MPV 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 14.5".
Side Return Air
(with transition and filter)
20" X25"X 1"
(508mm X635mm X 25mm)
Air Filter
/
Retu rn Air
Plenum
Transition
FIGURE 8
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 9
Page 10

Optional Return Air Base
(Upflow Applications Only -- For use with B, C and D cabinets only)
J
AIR FLOW
14
FU%CEL
7-1/4 (184)
i_ y
17-1/2 (446) RAB-B (98M60)
21 (533) RAB-C (98M58)
24-1/2 (622) RAB-D (98M59)
FRONT VIEW
OPTIONAL RAB
RETURN AIR BASE 7/8
(22)
I
O
4I123 (584)
102)1_l--- Overall 1Minimu_n_
I (Maximum) 11 (279) I
2Maximurq
I1Unit side return air
Opening 11_356)jn
5 8 SIDE RETURN
,_45_-1 AIR OPENINGS
(EitherSide).......................................................J.
ql_ 23 (584) "_u
_1-- 27-5/8 (702)
SIDE VIEW
f
122-7-16
(570)
Overall
Maximum)
_l
_ 3/4
(19)
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.
FIGURE 10
Leveling an 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 willensure proper draining of the heat exchanger.
Leveling Bolt Installation
Inches (mm)
3/8
(1o)
Furnace Front
3/8 1-3/4
(44)
1-3/4
(44)
Leveling Bolt
Leveling Bolt
Locations
3/8
(1o)
3/8 1-3/4
(10) (44)
t-3/4 (44)
FIGURE 11
Page 11

Downflow Applications
The unit may be installed three ways in downfiow 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.
After unit has been properly set in place, position provided
logo over existing logo and affix sticker on front panel.
Refer to figure 12 for clearances in downflow applica-
tions.
Downflow Application Installation Clearances
Top
Left Side Right Side
Bottom
Top 0
*Front 0
Back 0
Sides 0t
Vent 0
Floor NC$
*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.
SThe furnace may be installed on a combustible wood floor if an
optional additive base is installed between the furnace and the
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.
4 - Ensure that the seal is adequate.
TABLE 1
NON-COMBUSTIBLE FLOOR OPENING SIZE
Model No.
B Cabinet (17.5")
C Cabinet (21")
D Cabinet (24.5")
NOTE -Floor openin
Front to Rear
in. mm
19 - 3/4 502
19 - 3/4 502
19 - 3/4 502
Side to Side
in.
16 - 5/8
20-1/8
23 - 5/8
mm
422
511
6OO
dimensions listed are 1/4 inch (6 mm) larger than
the unit opening. See dimension drawing on page 2.
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 cabinet 21"- # 11M61
• D cabinet 24,5" - # 11M62
See table 2 for opening size to cut in floor,
A, CAUTION
TABLE 2
ADDITIVE BASE FLOOR OPENING SIZE
Model
B Cabinet (17.5")
C Cabinet (21")
D Cabinet (24.5")
2-
3-
Frontto Rear
in. mm
22 559
22 559
22 559
Side to Side
in.
18 - 3/4
22 - 3/4
25 - 3/4
mm
476
578
654
After opening is cut, set additive base into opening.
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,
Page 12

G61MPV UNIT
SUPPLY AIR PLENUM
PROPERLY
SIZED FLOOR _X_,J_€ "
OPENING I\\_ L_ ADDITIVE BASE
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
Return air may be brought in only through the top opening
of a furnace installed in the downflow position.The follow-
ing steps should be taken when installing plenum:
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.
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,
PLENUM ----__ I""11"_
(Field Provided) _ SECURE FROM
•_UTSIDE CABINET
/v II .. CABINET
SEALING STRIP _ IIJ SIDE PANEL
(Field Provided) ...... II
Side View II
FIGURE 14
PLENUM _
(Field Provided)
SECURE FROM
INSIDE CABINET Side View
SEALING STRIP
Field Provided)
CABINET
SIDE PANEL
FIGURE 15
Horizontal Applications
The G61MPV furnace can be installed in horizontal ap-
plications with either right- or left-hand air discharge,
Refer to figure 16 for clearances in horizontal applications,
================================================================================================
Horizontal Application
Installation Clearances
Right-Hand Discharge
Top
Left End Right End
Left-Hand Discharge
Top
Left End Right End
Bottom (Floor)**
i........................................i.............................................]
Front* iO
'.................... ....................t..............................................
I
Ends ! O
Floor iO:_
*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-I12" service clearance must be maintained below the unit to
provide for servicing of the condensate trap.
i :]:For installations on a combustible floor, do not install the fur-
l nace directly on carpeting, tile or other combustible materials oth-
Ler.t.h.an.w.°° d.f.I.°.°ri.n,g: ...............................................................
FIGURE 16
Page 13

TYPICAL HORIZONTAL ATTIC APPLICATION (FORCED AIR FURNACE)
INTAKE \
SAFTERS
BRACED FOR
SUPPORT
WASHER AND 2 NUTS \
LAG BOLT
SUPPORT ROD
*Gas connector may be used if acceptable
by the local authority 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)
j SUPPORT
FRAME
FIGURE 17
This furnace may be installed in either an attic or a crawl-
space. The G61MPV may also be installed as a unit heater.
Either suspend the furnace from roof rafters or floor joists,
as shown in figures 17 or 18, or install the furnace on a field-
fabricated raised platform, as shown in figure 19. The unit
must be supported at both ends and beneath the blower
deck to prevent sagging,
NQ TE -In horizontal applications, the unit must be lev-
el side-to-side. The unit may be tilted back-to-front a
maximum of 1" to ensure proper draining of the heat
exchanger. The heat exchanger coil will not drain properly
if the unit is tilted backward.
Installation of Horizontal Furnace
Suspended in Attic
NQ TE -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. 7 -
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. 8 -
4- Using 3/8 inch rods and support frame kit (ordered
separately), fabricate suspension hangers for unit
keeping in mind front service access clearances. 1 -
5 - Mount unit on support frame as shown in figure 18.
Unit must be level to ensure proper coil drainage. 2 -
6- Continue with exhaust, condensate and intake line
piping instructions.
BLOWER
ACCESS
PANEL
TYPICAL HORIZONTAL APPLICATION
BLOWER ACCESS PAN- 318 in, RODS
INTAKE/ExHAUST EL
CONNECTION _
DRA,N
SUPPORT FRAME (to protect finished space)
FIGURE 18
Hang drain pan below support frame as shown in fig-
ure 18. Leave 5-1/2 inches for service clearance be-
low unit for condensate trap,
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
Select location for unit keeping in mind service and
other necessary clearances. See figure 16,
Construct a raised wooden frame and cover frame
with a plywood sheet, Provide a service platform and
drain pan for unit,
Page 14

INTAKE
PIPE
*Gas connector may be
used for Canadian
installation if accept-
able by local authority
having junsdiction.
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.
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 (ordered separately) on top of blocks and install unit
on frame. Unit must be level to ensure proper heat ex-
changer coil drainage. Leave 5-1/2 inches for service
clearance) for condensate trap,
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,
G61MPV 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 raised 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 G61MPV 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,
Page 15

DISCHARGE AIR DUCT/GRILLE CABINET
18in. (457 mm) k ql
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,
NOTE -Wtlen installing duct/grille cabinet, take care not to damage internal unit
beater components when drilling holes or instalhng 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 draining
from this outlet will be easily noticed by the homeown-
er,
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,
*GAS CONNECTOR
INTAKE *Gas connector may be
PIPE used for Canadian instal-
lation if acceptable by lo-
cal authority havmg juds-
diction.
RAISE
CONDENSATE LINE PLATFORM
FIGURE 24
Return Air -- Horizontal Applications
Return air may be brought in only through the end of afur-
nace installed in the horizontal position. 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.
NOTE -In upflow applications where side return air fil-
ter is installed on same side as the condensate trap, fil-
ter rack must be installed beyond condensate trap to
avoid interference, 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) 24X25X 1(1)
Page 16

Useindustry-approvedstandardsto sizeandinstallthe
supplyandreturnairductsystem.Thiswillresultinaquiet
andlow-staticsystemthathasuniformairdistribution.
NOTE -Operation of this furnace in heating mode (indoor
blower operating at selected heating speed) with an exter-
nal static pressure which exceeds O.8 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. If present, this access panel must al-
ways 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.
CAUTION
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)
Primers and solvents must meet ASTM specifications.
PVC primer is specified in ASTM F 656. Use PVC solvent
cement as specified in ASTM D 2564 and ABS solvent ce-
ment as specified in ASTM D 2235. Low temperature sol-
vent cement is recommended. Metal or plastic strapping
may be used for vent pipe hangers.
When making ABS joints, pieces can be prepared with a
cleaner. When joining ABS to PVC materials, use PVC sol-
vent cement. Refer to the procedure specified in ASTM
D3138.
Canadian Applications Only - Pipe, fittings, primer and sol-
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 S636 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.
Page 17

TABLE 5
OUTDOOR TERMINATION KITS AND CORRESPONDING EQUIVALENCIES
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
3" Con-
centric
Kit
2" Wall
Kit with
Vent Ex-
tension
2" Wall
Ring Kit
2" Wall 3" Wall
Plate Kit Plate Kit
22G44 44J40
30G28 81J20
4 4*
5 5*
7 7*
14 14"
4 4*
5 5*
8 8*
14 14"
Not 1
Allowed
Not 2
Allowed
Not 2
Allowed
Not 4
Allowed
Not 2
Allowed
Not 2
Allowed
Not 4
Allowed
Not 6
Allowed
Not 10
Allowed
1-1/2" X 12" 2" X 12" 71M80 69M29 60L46 30G79 15F74
2 4 Not 12 Not Not 4 4
Allowed Allowed Allowed
2-1/2 5 Not 15 Not Not 5 5
Allowed Allowed Allowed
36B-045 3 7 Not 21 Not Not 7 7
Allowed Allowed Allowed
4 14 Not 42 Not Not 14 14
Allowed Allowed Allowed
2 4 Not 12 Not Not 4 4
Allowed Allowed Allowed
2-1/2 5 Not 15 Not Not 5 5
36B-070 Allowed Allowed Allowed
36B-071 3 8 Not 24 Not Not 8 8
Allowed Allowed Allowed
4 14 Not 42 Not Not 14 14
Allowed Allowed Allowed
2 Not 1 Not 3 3 Not 1"*
Allowed Allowed Allowed
2-1/2 Not 2 Not 6 6 Not 2**
60C-090 Allowed Allowed Allowed
60C-091 3 Not 2 Not 6 6 Not 2**
Allowed Allowed Allowed
4 Not 4 Not 12 12 Not 4**
Allowed Allowed Allowed
2-1/2 Not 2 Not 6 6 Not 2***
Allowed Allowed Allowed
60C-110 3 Not 2 Not 6 6 Not 2***
60C-111 Allowed Allowed Allowed
4 Not 4 Not 12 12 Not 4***
Allowed Allowed Allowed
3 Not 6 Not Not 15 Not 6***
Allowed Allowed Allowed Allowed
60D-135 4 Not 10 Not Not 25 Not 10"**
Allowed Allowed Allowed Allowed
*Requires field-provided and installed 1-1/2" exhaust accelerator.
**Requires field-provided and installed 2" exhaust accelerator.
***For use only in non-direct vent applications, when snow riser is
not required. Requires field-provided and installed 2" exhaust ac-
celerator.
Page 18

The G61MPV can be installed as either a Non-Direct
Vent or a Direct Vent gas central furnace.
NOTE -In Non-Direct Vent installations, combustion air is
taken from indoors and flue gases are discharged out*
doors. In Direct Vent installations, combustion air is taken
from outdoors and flue gases are discharged outdoors.
Intake and exhaust pipe sizing in Direct Vent applications
and exhaust pipe sizing in Non-Direct Vent applications --
Size pipe according to tables 6 and 7. Table 6 lists the mini-
mum equivalent vent pipe lengths permitted. Table 7 lists
the maximum equivalent pipe lengths permitted.
Maximum vent length is defined as:
Total length (linear feet) of pipe,
Plus Equivalent length (feet) of fittings,
Plus Equivalent length (feet) of termination.
NOTE -Include ALL pipe and ALL fittings, both in
doors and outdoors.
Regardless of the diameter of pipe used, the standard roof
and wall terminations described in section Exhaust Piping
Terminations should be used. Exhaust vent termination
pipe is sized to optimize the velocity of the exhaust gas as it
exits the termination. Refer to table 8.
NOTE -The exhaust pipe should be offset a minimum of 12
inches to avoid the possibility of water droplets being re-
leased from the exhaust termination. The minimum ex-
haust vent length is 15 ft. Shorter exhaust vent lengths may
result in the discharge of water droplets from the exhaust
termination, in spite of the 12-inch vertical offset. See fig-
ure 25.
Each 90° elbow (including those provided with the furnace)
of any diameter is equivalent to 5 feet (1.52m) of vent pipe
of the same diameter. Two 45° elbows are equivalent to
one 90° elbow of the same diameter. One 45° elbow is
equal to 2.5 feet (.76m) of vent pipe of the same diameter.
NOTE -On G61MPV-071, -091 and -111 units, sweep el-
bows must be used for all 90 °elbows in the venting
system when 2", 2-1/2" or 3" vent pipe is used. On
G61MPV-135, sweep elbows must be used for all 90 °el-
bows in the venting system when 3" vent pipe is used.
Sweep elbows are recommended for use in vent sys-
tems of other G61MPV units.
In some applications which permit the use of several differ-
ent sizes of vent pipe, a combination vent pipe may be
used. Contact Lennox' Application Department for assis-
tance in sizing vent pipe in these applications.
I
I
12" Min..1_
m
U_flow and DownflowApplication
Rooftop Termination
Horizontal Application
Rooftop Termination
Exhaust Pipe Offset
I
S
Upflow and Downflow Application
Side Wall Termination
12" iin.
I
II II
Horizontal Application
Side Wall Termination
FIGURE 25
Page 19

NOTE -The flue collar on all models is sized to accommo-
date 2" Schedule 40 flue pipe. When vent pipe which is
larger than 2" must be used in an upflow appfication, a 2"
elbow must be applied at the flue collar in order to properly
transition to the larger diameter flue pipe. This elbow must
be added to the elbow count used to determine acceptable
vent lengths. Assign an equivalent feet value to this elbow
according to the larger size pipe being used. Contact the
Appfication Department for more information concerning
sizing of vent systems which include multiple pipe sizes.
Use the following steps to correctly size vent pipe diameter.
Refer to Vent Pipe Size Determination Worksheet on
page 65.
1 - Determine the vent termination and its corresponding
equivalent feet value according to table 5,
2 - Determine the number of 90° elbows required for both
indoor and outdoor (e,g. snow riser) use. Calculate the
corresponding equivalent feet of vent pipe,
3 - Determine the number of 45° elbows required for both
indoor and outdoor use, Calculate the corresponding
equivalent feet of vent pipe.
4 - Determine the length of straight pipe required,
5- Add the total equivalent feet calculated in steps 1
through 4 and compare that length to the maximum
values given in table 7 for the proposed vent pipe di-
ameter. If the total equivalent length required exceeds
the maximum equivalent length listed in the appropri-
ate table, evaluate the next larger size pipe.
A, IMPORTANT
TABLE 6
MINIMUM VENT PIPE LENGTHS
G61MPV
MODEL
045,070,
071,090,
091
110,
111"*
135"**
MIN. EQUIV.
VENT LENGTH
15 ft.*
EXAMPLE
5 ft. plus 2 elbows of 2", 2-1/2", 3"
or 4" diameter pipe
5 ft. plus 2 elbows of 2-1/2" 3" or 4"
diameter pipe
5 ft, plus 2 elbows of 3" or 4"
diameter pipe
*Any approved termination may be added to the minimum equivalent
length listed.
**G61MPV-60C-110 and -111 must have 90°street ell (suppfied) installed
directly into unit flue collar.
***G61MPV-60D-135 must have 3" to 2" reducing eli (supplied) installed
directly into unit flue collar.
TABLE 7
MAXIMUM VENT PIPE LENGTHS
MAXIMUM EQUIVALENT VENT
G61MPV LENGTH FEET
ALTITUDE MODEL 2" 2-1/2" 3" 4"
PIPE PIPE PiPE PiPE
045 59 65 77 234
070 59 65 78 214
0711- 59 65 78 214
0 - 4500 090 26 42 72 204
(0 - 1371 m) 0911- 26 42 72 204
110" n/a 32 72 179
111"1- n/a 32 72 179
135"*:1: n/a n/a 61 160
045 59 65 77 234
070 59 65 78 214
0711- 59 65 78 214
4501-7500 090 26 42 72 204
(1372-2286 m) 0911- 26 42 72 204
110" n/a 32 72 179
111"1- n/a 32 72 179
135"*:I: n/a n/a 46 160
045 59 65 77 234
070 59 65 78 214
0711- 59 65 78 214
7501 - 10000 090 26 42 72 204
(2287 - 3048 m) 0911- 26 42 72 204
110" n/a 32 72 179
111"1- n/a 32 72 179
135"*:1: n/a n/a 46 160
n/a -- Not allowed.
*G61MPV-60C-110 and -111 must have 90°street eli (supplied) installed
directly into unit flue collar.
**G61MPV-60D-135 must have 3" to 2" reducing eli (supplied) installed
directly into unit flue collar.
_On G61MPV-071, -091 and -111 units, sweep elbows must be used
for afl 90° elbows in the venting system when 2", 2-1/2" or 3" vent
pipe is used. Sweep elbows are recommended for use in vent sys-
tems of other G61MPV units.
_On G61MPV-60D-135 units, sweep elbows must be used for all 90° el-
bows in the vent system when 3" vent pipe is used.
All cementing of joints should be done according to the
specifications outlined in ASTM D 2855.
A, WARNING
1 - Measure and cut vent pipe to desired length,
2 - Debur and chamfer end of pipe, removing any ridges
or rough edges, If end is not chamfered, edge of pipe
may remove cement from fitting socket and result in a
leaking joint,
3 - Clean and dry surfaces to be joined.
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