Lennox G71MPP-36B-070, G71MPP-60C-090, G71MPP-60D-135, G71MPP-36C-090, G71MPP-60C-110 Installation Instructions Manual
E Wvm)
_ 2007 Lennox Industries Inc.
Dallas, Texas, USA
®
INSTALLATION
INSTRUCTIONS
G71MPP SERIES UNITS
RETAIN THESE INSTRUCTIONS
FOR FUTURE REFERENCE
GAS UNITS
50&334M
03/2008 J LJ _,Publications
Unit Dimensions ............................... 2
G71MPP Parts Arrangement ..................... 3
Shipping and Packing List ....................... 4
Safety Information .............................. 4
General ....................................... 6
Installation - Setting Equipment .................. 6
Filters ........................................ 12
Duct System .................................. 13
Pipe & Fittings Specifications ................... 13
Vent Pipe Sizing Worksheet .................... 14
Vent Piping Guidelines ......................... 15
Joint Cementing Procedure ..................... 16
Venting Practices ............................. 17
Gas Piping ................................... 25
Electrical ..................................... 27
Integrated Control ............................. 33
Blower Motor Performance ..................... 40
Unit Start-Up ................................. 51
Gas Pressure Measurement .................... 52 ,
High Altitude Information ....................... 53
Other Unit Adjustments ........................ 54
Heating Sequence of Operation ................. 55
Service ...................................... 57
Ignition Control Diagnostic Codes ............... 59
Troubleshooting ............................... 60
Repair Parts List .............................. 66
Start-Up & Performance Check List .............. 66
Technical
Litho U.S.A.
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.
03/08
IIIHIININIIIIIIIIIIIIIIIIIIIIIIIIIIII
AWARNING
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.
505,334M
Page 1
IIIIIINIIIIIIIIIIIIIIIHIIIIIIIIIIIIIIIIIIIIIIII
1NOTE - 60C and 60D size units that require air volumes over
1800 cfm (850 L/s) must have one of the following:
a. 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.
b. Single side return air with optional RAB Return Air Base.
c. Bottom return air.
d. Return air from both sides.
e. Bottom and one side return air.
See Blower Performance Tables for additional information.
SUPPLY AIR
OPENING
Optional External Side Return Air Filter Kit (Upflow Only) is not
for use with the optional RAB Return Air Base.
,,_ A -_
,_v----- B -_D,.
9-9/16 (14)
2OPTIONAL
EXTERNAL
SIDE RETURN
AIR FILTER KIT
(Either Side)
11-5/8
(295) Right
9-3/4 (248)
Left
40
(1016)
t
AIR FLOW
2OPTIONAL I_ 25 (635)
EXTERNAL
SIDE RETURN
AIR FILTER KIT
(Either Side)
5-1/2
(140)t
t
6-1/2
(1_5)
4-1/8 6-3/4
(103) (171)
1-3/4 (45) Right
3-9/16 (91) Left -I_
(64)
A 2-1/2 .__
18-3/4 (476) (102 (584) i
I_ 28-1/2
J_ (724)
r_ COMBUSTIONAIR INTAKE
.... _ _ (Either Side)
( Iy \ / EXHAUSTAIROUTLET
9- _/_ Av (Either Side)
_11_y\ (Either Side)
L _ TRAPCONNECTION
°Oo_ (Either Side)
_p_,ql__ - (Either side )
04- --
I 23 _
• 1OPTIONAL 14
J (Either Side)
L Up-Flow Only
I RETURN CUTOUT (3.._6)
23-3/4 (603)
TOP VIEW
1.9_ 19-7/16_
GAsP,P,NG,NLET
\ .r_CONDENSATE
_ ELECTRICAL INLET
5/8(16)
Jl.--c 4-
3/4 (19) 1Bottom Return 4-1/4 1 Bottom Return
FRONT VIEW SIDE VIEW
--J_- 314(19)
Air Opening (108) Air Opening
9/16
'q'- (14)
1-15/16 (49)
Model No.
G71MPP-36B-070 17-1/2 446 16-3/8 416 16 406
G71MPP-36C-090
G71MPP-60C-090 21 533 19-7/8 454 19-1/2 495
G71MPP-60C-110
G71MPP-60D-135 24-1/2 622 23-3/8 546 23 584
in. mm in. mm in. mm
A B C
Page 2
HEATEXCHANGER
BURNERBOXASSEMBLY
BAGASSEMBLIES
(shippinglocation)
VARIABLE CAPACITY
GAS VALVE
COMBUSTION AIR
PRESSURE
SWITCHES
VARIABLE SPEED
COMBUSTION AIRINDUCER
BURNER ACCESS PANEL
BLOWER ACCESS PANEL
/
WARM HEADER
(COLLECTOR BOX)
CONDENSER COIL
PRESSURE SWITCH
ASSEMBLY WITH
PRESSURE
CONDITIONING
DEVICE
COLD HEADER
(COLLECTOR BOX)
SHIPPING BLOCK
(-135unitsonly)
VARIABLE SPEED
BLOWER MOTOR
SIGHT GLASS
TRANSFORMER
FIGURE 1
Page 3
INTEGRATED
CONTROL
TheG71MPPgasfurnaceisequippedwithavariable-ca-
pacity,variable-speedintegratedcontrol.Thiscontrolen-
surescompatibilitywithLennox'HarmonyIII'" zonecon-
trol system,as well as a thermostatwhichprovides
humiditycontrol.EachG71MPPisshippedreadyforinstal-
lationintheupflow,downflow,horizontalleftairdischarge
orhorizontalrightairdischargeposition.
Thefurnaceisequippedforinstallationinnaturalgasap-
plications.Aconversionkit(orderedseparately)isrequired
foruseinpropane/LPgasapplications.
The G71MPP can be installed only as a Direct Vent gas
central furnace.
NOTE- In Direct Vent installations, combustion air is taken
from outdoors and flue gases are discharged outdoors.
See figure 2 for applications including roof termination.
DIRECT VENT INSTALLATION
EXHAUST OUTLET
DANGER
&WARNING
COMBUSTION
AIR INTAKE
OUTSIDE OF
HOUSE
FIGURE 2
Package 1 of 1 contains
1 - Assembled G71MPP 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)
NOTE- G71MPP-60C-110 units also include a 2" diameter
PVC street elbow, which is shipped on the blower deck in
the heating compartment. G71MPP-60D-135 units are
shipped with a 3" to 2" PVC reducing elbow.
Check equipment for shipping damage. If you find any
damage, immediately contact the last carrier.
The following items may also be ordered separately:
1- Thermostat
1 - Propane/LP changeover kit
-&CAUTION
Use only the type of gas approved for use with this furnace.
Refer to unit nameplate.
G71MPP 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.
This furnace is CSA International certified for installation
clearances to combustible material as listed on the unit
nameplate and in the tables in figures 4, 9 and 13. Accessi-
bility 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.
For installation in a residential garage, the furnace must be
installed so that the burner(s) and the ignition source are
located no less than 18 inches (457 mm) above the floor.
The furnace must be located or protected to avoid physical
damage by vehicles. When a furnace is installed in a public
Page 4
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 G71MPP furnace may be used as a high-static unit
heater. The G71MPP 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 G71MPP 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.
A CAUTION
The G71MPP 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 G71MPP 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.
G71MPP 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
aflowed.
• 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.
• 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
,-& WARNING
In addition to the requirements outlined previously, the fol-
lowing general recommendations must be considered
when installing a G71MPP furnace:
• Place the furnace as close to the center of the air dis-
tribution system as possible. The furnace should also be
located close to the chimney or vent termination point.
• When the furnace is installed in an attic or other insu-
lated space, keep insulation away from the furnace.
• When the furnace is installed in an unconditioned
space, consider provisions required to prevent freezing
of condensate drain system.
,&,CAUTION
These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
having jurisdiction before installation.
SETTING EQUIPMENT
UPFLOW APPLICATION
UNIT MUST BE LEVEL SIDE-TO-SIDE IN ALL APPLICATIONS.
HORIZONTAL APPLICATION
I
-&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 side to side. The unit may be
tilted slightly (maximum 1/2 in.) from back to front to aid in
the draining of the heat exchanger. See figure 3.
DOWNFLOW APPLICATION
AIR FLOW
!,
I
O
t1"
AIR FLOW
FRONT VIEW
UNIT
FRONT
112"
max.
SIDE VIEW
UNIT MAY BE TILTED SLIGHTLY (MAX. 1/2") FROM BACK TO FRONT
FRONT VIEW
UNIT
FRONT
1/2"
I rflax,
END VIEW
TO AID IN THE DRAINING OF THE HEAT EXCHANGER.
FIGURE 3
Page 6
UNIT
FRONT
m
FRONT VIEW
©
1/2"
rflax.
SIDE VIEW
NOTE - G71MPP-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.
NOTE - G71MPP-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 4, 9 and 13,
WARNING
WARNING
Upflow Applications
The G71MPP gas furnace can be installed as shipped in
the upfiow position, Refer to figure 4 for clearances,
Installation Clearances
Top
LeftSide . _ RightSide
Bottom (Floor)
Top/Plenum 1 in. (25 ram)
*Front 0
Back 0
Sides 0-_
Vent 0
Floor 05
*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.
SFor 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 4
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 transition which will
accommodate 20x 25x I in. (508x 635x 25ram) air filter.
(Required to maintain proper air velocity.) See figure 5.
Page 7
2 - Return air from single side with optional RAB Return
Air Base. See figure 7.
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.
Side Return Air
(with transition and filter)
20" X 25" X 1"
(508mm X635mm X 25mm)
Air Filter
Return
Air
Plenum
G71MPP 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'"
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 6.
Removing the Bottom Panel
Screw,/
Cap
Bottom
FIGURE 5
FIGURE 6
Optional Return Air Base
(Upflow Applications Only -- For use with B, C and D cabinets only)
J
r 123(584) ---_-_
Overall
t
FURNACE
FRONT
_.t (Either Side)
17-1/2 (446) RAB-B (98M60) RETURN AIR BASE
21 (533) RAB-C (98M58) -I_ 27-5/8 (702) --I1,-
24-1/2 (622) RAB-D (98M59) 7/8
FRONT VIEW (22) SIDE 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 ram).
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.
t4
(356)
(Maximum) 1Minimu_ I
I 11(279) I
I air opening
' 1 Unit side return 14_56) i
5-5/8 SIDE RETURN AIR
(143) OPENINGS
2 Maximum I
t-
-- 23 (584)OPTIONAL RAB
f
122-7-16
(570)
Overall
(Maximum)
_l
-T
3/4
(19)
FIGURE 7
Page 8
SettinganUpflowUnit
Whenthesidereturnairinletsareusedinanupflowap-
plication,itmaybenecessarytoinstallshimsonthebottom
ofthefurnace.Ifdesired,usefield-suppliedcorrosion-re-
sistant5/16inchmachinebolts(4)andnuts(8)tolevelthe
furnace,Seefigure8,
NOTE - The maximum length of the bolt is 1-1/2 inches.
1 - Lay 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 8 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,
Leveling Bolt Installation
Inches (mm)
3/8
Furnace Front _¢
3/8 1-3/4
(44)
Downflow Application Installation Clearances
Top
LeftSide _ RightSide
Boffom
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 9
1-3/4
(44)
Furnace
Bottom
Leveling Bolt
Locati,
3/8 1-3/4
(10) (44)
I-3/4 (44)
Leveling Bolt
Locations
3/8
(10)
FIGURE 8
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 coil
cabinet. Do not drag the unit across the floor in the
downflow position. Flange damage will result.
Refer to figure 9 for clearances in downflow applica-
tions.
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
Model No.
B Cabinet (17.5") 502
CCabinet(21") 502
DCabinet(24.5") 502
NOTE - Floor opening dimensions listed are 1/4 inch (6 mm) larger than
the unit opening. See dimension drawing on page 2.
Front to Rear
in.
19 - 3/4
19 - 3/4
19 - 3/4
mm
)PENING SIZE
Side to Side
in. mm
16 - 5/8 422
20-1/8 511
23 - 5/8 600
Page 9
Installation on Combustible Flooring
(Using an Additive Base)
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. See
table 2 for opening size to cut in floor.
AkCAUTION
TABLE 2
ADDITIVE BASE FLOOR OPENING SIZE
Cabinet
Width
B Cabinet
(17.5")
C Cabinet
(21")
D Cabinet
(24.5")
Catalog
Number
11M60
11M61
11M62
Frontto Rear
in. mm
22 559
22 559
22 559
Side to Side
in. mm
18 - 3/4 476
22 - 3/4 578
25 - 3/4 654
5 - Set the furnace over the plenum,
6 - Ensure that the seal between the furnace and plenum
is adequate.
Installation on Cooling Coil 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 11 or 12).
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,
SUPPLY AIR PLENUM
G71MPP UNIT_ __T
PROPERLY
R ,VEBASE
FIGURE 10
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.
PLENUM --*.._ I"'t'_ "_
(Field Provided) _ SECURE FROM
• _L_UTSIDE CABINET
/ v II J CABINET
SEALING STRIP _ II./ SIDE PANEL
(Field Provided) ...... II
Side View II
FIGURE 11
PLENUM
(Field Provided_-._
SECURE FROM
INSIDE CABINET Side View
SEALING STRIP
,_/.J.Field Provided)
/ CABINET
, SIDE PANEL
FIGURE 12
Page 10
Horizontal Applications
The G71MPP furnace can be installed in horizontal ap-
plications with either right- or left-hand air discharge,
The G71MPP may also be installed as a unit heater. Either
suspend the furnace as shown in figure 14, or install the fur-
nace on a field-fabricated raised platform. The unit must be
supported at both ends and beneath the blower deck to
prevent sagging,
Refer to figure 13 for clearances in horizontal applications,
3 - If unit is installed above finished space, 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 or field-fabri-
cated supports, fabricate suspension hangers, keep-
ing in mind front service access clearances.
5 - Mount unit on support frame as shown in figure 14,
6- Continue with exhaust, condensate and intake line
piping instructions,
Horizontal Application
Installation Clearances
Right-Hand Discharge
Top
Left End
Air
Flow
Bottom (Floor)**
) / Right End
_ Air
• Flow
Left-Hand Discharge
Top
Left End
Air
Flow
Right End
Air
Flow
Bottom (Floor)**
Top 6
Front* 6
Back 6
Ends 6
Vent 6
Floor 65
*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 13
Suspended Installation of Horizontal Unit
NOTE- If unit is suspended, horizontal support kit (Cat No.
56J18 ordered separately) or equivalent is recommended
to ensure proper unit support and coil drainage.
1 - Select location for unit keeping in mind service and
other necessary clearances. See figure 13,
2 - Provide service platform in front of unit,
TYPICAL HORIZONTAL APPLICATION
BLOWER ACCESS 3/8 in. RODS
PANEL l
CONNECTION
©
DRAIN PAN
SUPPORT FRAME (to protect finished space)
FIGURE 14
_
If unit is suspended above finished space, hang the
field-provided drain pan below the support frame as
shown in figure 14. Leave 5-1/2 inches for service
clearance below unit for condensate trap,
_
Route auxiliary drain line so that water draining from
this outlet will be easily noticed by the homeowner, If
necessary, run the condensate line into a condensate
pump to meet drain line slope requirements, The
pump must be rated for use with condensing furnaces,
Protect the condensate discharge line from the pump
to the outside to avoid freezing.
Platform Installation of Horizontal Unit
_
Select location for unit keeping in mind service and
other necessary clearances, See figure 13,
2-
Construct a raised wooden frame and cover frame
with a plywood sheet, Provide a service platform in
front of unit, If unit is installed above finished space,
fabricate a drain pan to be installed under unit.
When installing the unit in a crawl space, a proper sup-
port platform may be created using cement blocks and
the horizontal support frame kit (ordered separately,
Page 11
Lennoxpartnumber56J18).Positionthe support
frameontopoftheblocksandinstalltheunitonthe
frame.Leave5-1/2inchesforserviceclearancefor
condensatetrap.
EXHAUST PIPE
*Gas connector may be
used for Canadian
installation ff accept-
able by local authority
having jurisdiction.
INTAKE
CONDENSATE
LINE SERVICE PLATFORM
FIGURE 15
*GAS
CONNECTOR
RAISED
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 16.
2 - Flange both ends of duct/grille cabinet so that screws
can be used to secure cabinet to discharge end of unit
heater.
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 16,
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.
3 - Route auxiliary drain line so that water draining from
this outlet will be easily noticed by the homeowner. If
necessary, run the condensate line into a condensate
pump to meet drain line slope requirements. The
pump must be rated for use with condensing furnaces.
Protect the condensate discharge line from the pump
to the outside to avoid freezing.
4 - Set unit in drain pan as shown in figure 15. 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.
G71MPP 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.
The G71MPP may also be installed as a unit heater. Either
suspend the furnace from roof rafters or floor joists, as
shown in figure 14, or install the furnace on a field-fabri-
cated raised platform, as shown in figure 15. The unit must
be supported at both ends and beneath the blower deck to
prevent sagging.
Unit Heater Discharge Duct Guidelines
A field-fabricated and installed discharge air duct and grille
cabinet is suitable for use with the G71MPP heater. See fig-
ure 16, Keep the following items in mind when constructing
the cabinet,
DRAIN PA_
NOTE _ Wtlen installing duct/grille cabinet, take care not to damage internal unit
beater components wben drilling boles or installing screws.
FIGURE 16
Return Air -- Horizontal Applications
Return air may be brought in only through the end of a fur-
nace installed in the horizontal position. The furnace is
equipped with a removable bottom panel to facilitate instal-
lation. See figure 6.
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 Width
B Cabinet (17-1/2")
C Cabinet (21")
D Cabinet (24-1/2")
Side Return Bottom Return
16X25Xl(1) 16X25Xl(1)
16X25Xl(1) 20X25Xl(1)
16X25Xl(2) 24X25Xl(1)
Filter Size
Page 12
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 table 4 for approved piping and fitting materials.
TABLE 4
PIPING AND FITTINGS SPECIFICATIONS
PIPE & FITTING MATERIAL
Schedule 40 PVC (Pipe) D1785
Schedule 40 PVC (Cellular Core Pipe) F891
Schedule 40 PVC (Fittings) D2466
Schedule 40 CPVC (Pipe) F441
Schedule 40 CPVC (Fittings) F438
SDR-21 PVC or SDR-26 PVC (Pipe) D2241
SDR-21 CPVC or SDR-26 CPVC (Pipe) F442
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)
ASTM
SPECIFICATION
_ CAUTION
Use PVC solvent cement as specified in ASTM D2564 and
ABS solvent cement as specified inASTM D2235. Primers
and solvents must meet ASTM specifications. PVC primer
is specified in ASTM F656. As an alternate, use all purpose
cement, as specified in ASTM performance requirements
D-2564, D-2235 and F493 to bond ABS, PVC, or CPVC
pipe when using fittings and pipe made d the same materi-
als. Use transition solvent cement when bonding ABS to ei-
ther PVC or CPVC. Low temperature solvent cement is rec-
ommended. Metal or plastic strapping may be used for vent
pipe hangers.
Uniformly apply a liberal coat of PVC primer for PVC or use
a clean dry cloth for ABS to clean inside socket surface of
fitting and male end d pipe to depth of fitting socket. Refer
to the procedure specified in ASTM D3138.
Canadian Applications Only - Pipe, fittings, primer and
solvent cement used to vent (exhaust) this appliance must
be certified to ULC S636 and supplied by a single
manufacturer as part of an approved vent (exhaust) sys-
tem. When bonding the vent system to the furnace, use
ULC $636 approved One-Step Transition Cement to bond
the pipe to the flue collar, or to bond the 90 ° elbow or re-
ducing 90° elbow to the flue collar. 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.
Page 13
OUTDOOR TERMINATION KITS AND CORRESPONDING EQUIVALENCIES
Outdoor Ex- Outdoor Ex-
VENT haust Accel- haust Accel- 1-112"
UNIT PIPE erator erator Concentric
MODEL DIA. (Dia. X (Dia. X Kit
(in.) Length) Length)
1-1/2" X 12" 2"X 12" 71M80 69M29 60L46 30G28 81J20 15F74
TABLE 5
Vent Pipe Length Equivalency (feet)
2" Con- 3" Con- 2" Wall Plate 3" Wall 2" Wall
centric Kit centric Kit Kit Plate Kit Ring Kit
22G44 44J40
2 4 Not 12 Not Not 4 4* 4
2-1/2 5 Not 15 Not Not 5 5* 5
36B-070
60C-090
60C-110 3 Not 2 Not 6 6 Not 2 2
60D-135
*Requires field-provided and installed 1-1/2" exhaust accelerator.
3 8 Not 24 Not Not 8 8* 8
4 14 Not 42 Not Not 14 14" 14
2 Not 1 Not 3 3 Not 1 1"*
2-1/2 Not 2 Not 6 6 Not 2 2**
3 Not 2 Not 6 6 Not 2 2**
4 Not 4 Not 12 12 Not 4 4**
2-1/2 Not 2 Not 6 6 Not 2 2
4 Not 4 Not 12 12 Not 4 4
3 Not 6 Not Not 15 Not 6
4 Not 10 Not
Allowed Allowed Allowed
Allowed Allowed Allowed
Allowed Allowed Allowed
Allowed Allowed Allowed
Allowed Allowed Allowed
Allowed Allowed Allowed
Allowed Allowed Allowed
Allowed Allowed Allowed Allowed Allowed
Allowed Allowed
Allowed Allowed Allowed
Allowed Allowed Allowed
Allowed Allowed Allowed
Allowed Allowed Allowed
Not 25 Not 10
Allowed Allowed Allowed
**Requires field-provided and installed 2" exhaust accelerator.
Not
Not
Step 1
Step 2
Proposed vent pipe size :
Termination kit catalog number :
Vent pipe equivalency value from table 5 :
Step 3
Total number of 90 ° elbows required (indoors and outdoors)
X 5 = equivalent feet of pipe
Step 4
Total number of 45 ° elbows required (indoors and outdoors)
X 2.5 = equivalent feet of pipe
Step 5
Step 6
Linear feet of straight pipe required :
Add equivalent feet of vent pipe listed in
steps 2 through 5.
If the total is equal to, or less than, the allowable maximum given in table 7, the proposed pipe size is acceptable. If the
total exceeds the maximum allowed vent pipe length, repeat the process above using the next larger diameter pipe until
an acceptable total is achieved.
NOTE - In Direct Vent systems, total the equivalent length of either the exhaust OR intake piping run, depending upon which
will be LONGER. Intake and exhaust pipe diameter must be the same size and must be terminated in the same pressure
zone. Intake and exhaust pipe should be roughly the same length.
Equivalent Feet
TOTAL
Page 14
The G71MPP can be installed only as a Direct Vent gas
central furnace.
NOTE- In Direct Vent installations, combustion air is taken
from outdoors and flue gases are discharged outdoors.
Intake and exhaust pipe sizing -- Size pipe according to
tables 6 and 7. Table 6 lists the minimum equivalent vent
pipe lengths permitted. Table 7 lists the maximum equiva-
lent 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 indoors
and outdoors. Measure equivalent length of intake and
exhaust pipe separately. Use the greater of the two
lengths to determine vent pipe diameter to be used for
both intake and exhaust.
Regardless of the diameter of pipe used, the standard roof
and wall terminations described in section Exhaust Piping
Exhaust Pipe Offset
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 figure
17,
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) d vent pipe of the same diameter.
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
_'q 12" Min. t1_
m
Upflow and Downflow Application
Rooftop Termination
"br"
12" Min. "1_1
I
Horizontal Application
Rooftop Termination
m
Upflow and Downflow Application
Side Wall Termination
_1- 12" Min. -I_
I
I)
Horizontal Application
Side Wall Termination
I
FIGURE 17
Page 15
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 application, 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.
Contact the Application 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.
TABLE 7
MAXIMUM VENT PIPE LENGTHS
MAXIMUM EQUIVALENT VENT
ALTITUDE
0 - 7500 090 50 100 125 225
(0 - 2286 m) 110" 20 60 125 200
7501 - 10000 090 25 60 125 225
(2287 - 3048 m) 110" n/a 40 90 200
n/a -- Not allowed.
*G71MPP-60C-110 must have 90° street eli (supplied) installed directly
into unit flue collar.
**G71MPP-60D-135 must have 3" to 2" reducing eli (supplied) installed
directly into unit flue collar.
NOTE - Elbows and pipe required for vent terminations must be added
when calculating equivalent vent length.
G71MPP LENGTH FEET
MODEL 2" 2-1/2" 3" 4"
PIPE PIPE PiPE PiPE
070 75 135 150 250
135"* n/a n/a 125 180
070 60 125 150 250
135"* n/a n/a 70 180
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 more than one diameter of pipe is being
used, use the appropriate value from table 7 for the
larger sized pipe, If the total equivalent length required
exceeds the maximum equivalent length listed in the
appropriate table, evaluate the next larger size pipe.
AIMPORTANT
TABLE 6
MINIMUM VENT PIPE LENGTHS
G71MPP
MODEL
070,090
110"*
135"**
*Any approved termination ma
length listed.
**G71MPP-60C-110 must have 90 ° street eli (suppfied) installed directly
into unit flue collar.
***G71MPP-60D-135 must have 3" to 2" reducing eli (supplied) installed
directly into unit flue collar.
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
, be added to the minimum equivalent
All cementing of joints should be done according to the
specifications outlined in ASTM D 2855.
,& DANGER
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,
4- Test fit joint and mark depth of fitting on outside of
pipe,
5 - Uniformly apply a liberal coat of PVC primer for PVC or
use a clean dry cloth for ABS to clean inside socket
surface of fitting and male end of pipe to depth of fitting
socket,
NOTE - Furnace flue collar and air inlet fitting are both
made of ABS material. Use transition solvent cement
when joining ABS fittings to PVC pipe,
6 - Promptly apply solvent cement to end of pipe and in-
side socket surface of fitting. Cement should be ap-
plied lightly but uniformly to inside of socket, Take care
to keep excess cement out of socket, Apply second
coat to end of pipe,
NOTE- Time is critical at this stage. Do not allow prim-
er to dry before applying cement.
Page 16
7- Immediatelyafterapplyinglastcoatofcementtopipe,
andwhilebothinsidesocketsurfaceandendofpipe
arewetwithcement,forcefullyinsertendofpipeinto
socketuntilitbottomsout.TurnPVCpipe1/4turndur-
ingassembly(butnotafterpipeisfullyinserted)todis-
tributecementevenly.DONOTturnABSorcellular
corepipe.
NOTE - Assembly should be completed within 20 sec-
onds after last appfication of cement. Hammer blows
should not be used when inserting pipe.
8 - After assembly, wipe excess cement from pipe at end
of fitting socket. A properly made joint will show a bead
around its entire perimeter. Any gaps may indicate a
defective assembly due to insufficient solvent.
9 - Handle joints carefully until completely set.
The thickness of construction through which vent pipes
may be installed is 24" (610mm) maximum and 3/4"
(19mm) minimum. If a G71MPP furnace replaces a furnace
which was commonly vented with another gas appliance,
the size d the existing vent pipe for that gas appliance must
be checked. Without the heat of the original furnace flue
products, the existing vent pipe is probably oversized for
the single water heater or other appliance. The vent should
be checked for proper draw with the remaining appliance.
1 - Use recommended piping materials for exhaust pip-
ing.
2 - Secure all joints so that they are gas-tight using ap-
proved cement.
Suspend piping using hangers at a minimum of every
5 feet (1.52m) for sched-
ule 40 PVC and every 3
feet (.91m) for ABS-DWV,
PVC-DWV, SPR-21 PVC,
and SDR-26 PVC piping.
A suitable hanger can be
fabricated by using metal
or plastic strapping or a
large wire tie.
3- In areas where piping penetrates joists or interior
walls, hole must be large enough to allow clearance on
all sides of pipe through center of hole using a hanger.
4 - Isolate piping at the point where it exits the outside wall
or roof in order to prevent transmission of vibration to
the structure.
5 - When furnace is installed in a residence where unit is
shut down for an extended period of time, such as a
vacation home, make provisions for draining conden-
sate collection trap and lines.
STRAPPING
(metal, plastic
large wire
ties)
FIGURE 18
Exhaust Piping (Figures 19 and 20)
NOTE- A 2" diameter PVC street ell is located on the blow-
er deck of 60C-110 units, Street ell must be_glued using
transition solvent cement directly into the unit flue collar.
See figure 19. A 3"to 2" PVC reducing ell is located on the
blower deck of the 60D-135 units, In upflow or downflow
applications, the reducing ell must be glued using transi-
tion solvent cement directly into the unit flue collar.
1 - Choose the appropriate side for venting in upflow or
downflow positions, Exhaust piping exits from the top
of the unit in horizontal air discharge applications.
Glue the field-provided exhaust vent pipe (or provided
street ell or reducing ell in upflow or downflow applica-
tions) to the flue collar, All PVC cement joints should
be made according to the specifications outlined in
ASTM D 2855. Refer to pipe and fittings specifications
and gluing procedures,
A, IMPORTANT
2 - All horizontal runs of exhaust pipe must slope back to-
ward unit. A minimum of 1/4" (6mm) drop for each 12"
(305mm) of horizontal run is mandatory for drainage.
Horizontal runs of exhaust piping must be supported
every 5 feet (1,52m) using hangers.
NOTE - Exhaust piping should be checked carefully to
make sure there are no sags or low spots.
3 - On the opposite side of the cabinet, glue the provided
2" vent plug into the unused flue collar,
4- Route piping to outside of structure, Continue with
installation following instructions given in piping ter-
mination section.
A, CAUTION
Ak CAUTION
Page 17
PLUG
TYPICAL EXHAUST PIPE CONNECTIONS AND CONDENSATE TRAP INSTALLATION
IN UPFLOW OR DOWNFLOW DIRECT VENT APPLICATIONS
(Right-Hand Exit in Upflow Application Shown) 45°
2-1/2",
3", OR
4"
TRANSiTiON
MAX
45 °
MAX
t
VENT PLUG
(Must be
glued in
place)
PLUG
"2" diameter street elbow provided.
**3" to 2" diameter reducing elbow provided.
*** Max 2" pipe length between reducing
elbow and transition when 4" pipe is used.
TYPICAL EXHAUST PIPE CONNECTIONS
HORIZONTAL DIRECT VENT APPLICATIONS
(Horizontal Right-Hand Air Discharge Application Shown)
*2" maximum length -36B-070
for -135 only. -60C-090
2" or -090 with SIDE ViEW
CONDENSATE
TRAP
(Must be installed
on same side as
exhaust piping)
-36C-090
.60C.110"
.60D-135"
TRANSiTiON
G71 MPP-070,
2-1/2", 3", or4"
vent pipe
2-1/2", p:>_]
3":4OR _ TRANSmON
TRANSITION _ pipe is
G71MPP-110 with
2-1/2", 3", OR 4" G71MPP-135 with
vent pipe 3" OR 4" vent pipe
(useonly if 4"
required)
Ft /2 ....
FIGURE 19
Intake Piping
The G71MPP furnace may be installed only in direct vent
applications,
The G71MPP unit is designed for either left-side or right-
side air intake connections in either upflow or downflow ap-
plications. In horizontal applications, air intake must be
brought in through the top, Intake air piping is independent
of exhaust piping,
DO NOT transition from
smaller to larger pipe
size in horizontal runs.
,,1"36C'090
FIGURE 20
2"
-36B-070
-60C-090
IO
Page 18
TYPICAL AIR INTAKE PIPE CONNECTIONS
UPFLOW OR DOWNFLOW DIRECT VENT APPLICATIONS
(Right-Hand Exit in Upfiow Application Shown)
3" OR
2-1/2", [:_
4'
PLUG
(Must be
glued in
place)
-36B-070
-36C-090
-60C-090
TYPICAL AIR INTAKE PIPE CONNECTIONS
HORIZONTAL DIRECT VENT APPLICATIONS
(Horizontal Right-Hand Air Discharge Application Shown)
*Limit pipe -36B-070
length to 4" in -60C-090
- 135 applications. -60C-110
-36C-090
-60D-135"
TRANSITION
2"*
2-1/2",
3" OR 4"
-36B-070
-36C-090
-60C-090
-60C-110
FIGURE 21
TRANSITION [_2"
-36B-070
-36C-090
-60C-090
-60C-110
*Limit pipe length to 4" in
G 71MPP-135 applications.
TRANSITION
-36B-070
-36C-090
-60C-090
-60C-110
-60D-135"
-36B-070
-36C-090
-60C-090 2,,L_
FIGURE 22
Page 19
VENT TERMINATION CLEARANCES
FOR INSTALLATIONS IN THE USA AND CANADA*
[] - G71MPP VENT TERMINATION
O - AIR INLET OF OTHER APPLIANCE
D!
A - Clearance above grade - 12 in. (305mm) minimum.
B - Clearance to window or door that may be opened -
for vent installations in USA- 12 in (305mm) minimum.
for vent installations in Canada - 12 in. (305mm) mini-
mum for appliances _ 100,000 Btuh (30 kW);
36 in (09m) minimum for appliances > 100,000 Btuh (30
kW)
C - Do not position terminations directly under roof eaves.
D - Clearance to electric meters, gas meters, regulators, and
refief equipm ent -
for vent installations in USA -48 in (1219mm) minimum.
for vent installations in Canada - see current edition of
CSA B149 Code
* Note -
(I) Dimensions are from the current edition of The National Fuel Gas Code - ANSI-Z22& 1/NFPA 54 for USA installa-
tions. In Canada, refer to current edition of CSA B149 installation codes. Local codes or regulations may require different
clearances.
(11)In Non-Direct Vent installations, combustion air is taken from indoors and the flue gases are discharged to the outdoors.
E - Clearance to non-mechanical air supply inlet or outlet
for vent installations in USA -48 in. (1219mm) minimum
horizontal and below, 12 in, (305ram) minimum above.
for vent installations in Canada - 12 in. (305mm) mini-
mum for appliances _ 100,000 Btuh (30 kW);
36 in, (0.9m) minimum for appliances > 100,000 Btuh (30
kW).
F - Clearance to mechanical air supply inlet --
for vent installations in USA - 36 in. minimum (914mm).
G - Clearance to mechanical air supply inlet --
for vent installations in Canada - 72 in. (1829mm) mini-
mum.
H - Do notpoint terminations into recessed areas such as win-
dow wells, stairwells or alcoves.
J - Do not position terminations directly above a pubfic walk-
way.
FIGURE 23
Page 20
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