ICP N9MP2125J20A1 Installation Guide
N9MP2
Four Position Condensing Gas Furnace
SAFETY REQUIREMENTS
Recognize safety information. This is the safety-alert symbol/X X. When you see this symbol on the furnace and in instructions or
manuals be alert to the potential for personal injury.
Understand the signal words DANGER, WARNING, or CAUTION. These words are used with the safety-alert symbol. DANGER
identifies the most serious hazards, those that will result in severe personal injury or death. WARNING signifies a hazard that could
result in personal injury or death. CAUTION is used to identify unsafe practices that could result inminor personal injury or product and
property damage.
Installing and servicing heating equipment can be hazardous due to gas and electrical components. Only trained and qualified person-
nel should install, repair, or service heating equipment.
Untrained service personnel can perform basic maintenance functions such as cleaning and replacing air filters. All other operations
must be performed by trained service personnel. When working on heating equipment, observe precautions in the literature, on tags,
and on labels attached to or shipped with the unit and other safety precautions that may apply.
Follow all safety codes. In the United States, follow all safety codes including the current edition National Fuel Gas Code (N FGC) NFPA
No. 54/ANSIZ223.1. In Canada, refer to the current edition of the National Standard Canada CAN/CGA-B149.1 - and .2-M91 Natural
Gas and Propane Installation Codes (NSCNGPIC). Wear safety glasses and work gloves. Have fire extinguisher available during start-
up and adjustment procedures and service calls.
These instructions cover minimum requirements and conform to existing national standards and safety codes. In some instances,
these instructions exceed certain local codes and ordinances, especially those that may not have kept up with changing residential
construction practices. We requre these instructions as a minimum for a safe installation.
Table of Contents
1.SafeInstallationRequirements................. 4
2.Installation................................ 5
3.Combustion&VentilationAir .................. 8
4.Vent& CombustionAirPiping ................ 10
5.GasSupplyandPiping ...................... 24
6.ElectricalWiring ........................... 28
Manufactured by:
International Comfort Products Corporation (USA)
Lewieburg, TN USA 87091
7.DuctworkandFilter(Upflow/Horizontal)......... 29
8. ChecksandAdjustments.................... 33
9.FurnaceMaintenance ....................... 35
10.SequenceofOperation&Diagnostics.......... 35
11.ConcentricVentTermination................. 40
Fire or Explosion hazard.
This furnace is not designed for use in mobile
homes, trailers or recreational vehicles.
Such use could result in death, bodily injury
and/or property damage.
Printed in U.S.A. LP1 10/8/2001 440 01 1011 00
N9MP1 - Indoor combustion air (1 pipe only)
N9MP2 - Direct Vent ONLY (2 pipe only)
*9MPD - Dual Certified Venting (1 or 2 pipes)
*Denotes Brand
*9
Brand
Brand Identifier
8 = Non-Condensing, 80+% Gas Furnace
9 = Condensing, 90+% Gas Furnace
Installation Configuration
UP = Upflow
DN = Downfiow
UH = Upflow/Horizontal
HZ = Horizontal
DH = Downfiow/Horizontal
MP = Multiposition, Upflow/Downflow/Horizontal
Major Design Feature
= One (Single) Pipe
2 = Two Pipe
D=I or2Pipe
L = Low NOx
* Denotes Brand
N = Single Stage
P = PVC Vent
T = Two Stage
V = Variable Speed
MP D 0 75 F 12
A # EngineeringRev.
L Denotes minor changes
MarketingDigit
Denotes minor change
Cooling Airflow
08 = 800 CFM
12 = 1200 CFM
14 = 1400 CFM
16 = 1600 CFM
20 = 2000 CFM
Cabinet Width
B = 15.5" Wide
F = 19.1" Wide
J = 22.8" Wide
L = 24.5" Wide
Input (NominalMBTUH)
Printed in U.S.A. LP1 10/8/2001 440 01 1011 00
Dealer Name:
START-UP CHECK SHEET
For 90+ Furnace
(Keep this page for future reference)
Address:
City, State(Province), Zip or Postal Code:
Phone:
Owner Name:
Address:
City, State(Province), Zip or Postal Code:
Model Number:
Serial Number:
Type of Gas: Natural: [_
Which blower speed tap is used?
(Heating). (Cooling)
LP: _1
Business Card Here
Manual Gas Shut-Off Upstream
of Furnace/Drip-Leg?
Condensate Drain Connected?
Condensate Drain Trapped? YES [_
Transition Pressure switch hose relocated for U/D/H
Application? YES _ NO _
Blower Speed Checked? YES _1 NO _1
All Electrical Connections Tight? YES _1 NO _1
Gas Valve OK? YES _ NO _
Measured Line Pressure When Firing Unit:
YES _1 NO _1
YES _1 NO _1
NO_1
Temperature of Supply Air:
Temperature of Return Air:
Rise (Supply Temp,-Return Temp,): (°F) or(°C).__
Filter Type and Size:
Fan "Time ON" Setting:
Fan "Time OFF" Setting:
Dealer Comments:
44001 101100
(°F). or(°C).
(°F) or(°C)
Calculated Firing Rate:(See Checks andAdjustments Sec-
tion),.
Temperature Rise (supply-return temperature):(°F)__
Measured Manifold Gas Pressure:
Static Pressure (Ducts): Supply Air Return
Date of Start-Up:
CO ?
0O2 ?
1. Safe Installation Requirements
Installation or repairs made by unqualified
persons can result in hazards to you and others.
Installation MUST conform with local codes or, in
the absence of local codes, with codes of all
governmental authorities having jurisdiction.
The information contained in this manual is
intended for use by a qualified service technician
who is experienced in such work, who is familiar
with all precautions and safety procedures
required in such work and is equipped with the
proper tools and test instruments.
Failure to carefully read and follow all instruc-
tions in this manual can result in furnace
malfunction, death, personal injury and/or
property damage.
NOTE: This furnace is design certified by the Canadian Stan-
dards Association (CSA) for installation in the United States and
Canada. Refer to the appropriate codes, along with Figure 1 or
Figure 2 and this manual, for proper installation.
• This furnace is NOT approved for installation in
mobile homes, trailers or recreation vehicles,
• Do NOT use this furnace as a construction heater or to
heat a building that is under construction.
Use only the Type of gas approved for this furnace (see
Rating Plate on unit). Overfiring will result in failure of
heat exchanger and cause dangerous operation. (Fur-
naces can be converted to LR gas with approved kit.)
• Do NOT use open flame to test for gas leak.
• Ensure adequate combustion and ventilation air is pro-
vided to the furnace.
• Seal around supply and return air ducts.
• The vent system MUST be checked to determine that it is
the correct type and size.
• Install correct filter type and size.
• Unit MUST be installed so electrical components are
protected from direct contact with water.
NOTE: It is the personal responsibility and obligation of the end
user to contact a qualified installer to ensure that the installation is
adequate and conforms to governing codes and ordinances.
Safety Rules
Your unit is built to provide many years of safe and dependable
service provided it is properly installed and maintained. However,
abuse and/or improper use can shorten the life of the unit and
create hazards for you, the owner.
A. The U.S. Consumer Product Safety Commission recom-
mends that users of gas- burning appliances install carbon
monoxide detectors. There can be various sources of car-
bon monoxide in a building or dwelling. The sources could
be gas-fired clothes dryers, gas cooking stoves, water
heaters, furnaces, gas-fired fireplaces, wood fireplaces,
and several other items. Carbon monoxide can cause seri-
ous bodily injury and/or death. Therefore, to help alert
people of potentially dangerous carbon monoxide levels,
you should have carbon monoxide detectors listed by a na-
tionally recognized agency (e.g. Underwriters Laborato-
ries or International Approval Services) installed and
maintained in the building or dwelling (see Note below).
Carbon monoxide or "CO" is a colorless and odorless gas
produced when fuel is not burned completely or when the
flame does not receive sufficient oxygen.
B. There can be numerous sources of fire or smoke in a build-
ing or dwelling. Fire or smoke can cause serious bodily in-
jury, death, and/or property damage. Therefore, in order to
alert people of potentially dangerous fire or smoke, you
should have fire and smoke detectors listed by Underwrit-
ers Laboratories installed and maintained in the building or
dwelling (see Note below).
Note: The manufacturer of your furnace does not test any de-
tectors and makes no representations regarding any brand
or type of detector.
C. To ensure safe and efficient operation of your unit, you
should do the the following:
1. Thoroughly read this manual and labels on the unit.
This will help you understand how your unit operates and
the hazards involved with gas and electricity.
2. Do not use this unit if any part has been under water.
Immediately call a qualified service technician to inspect
the unit and to replace any part of the control system and
any gas control which has been under water.
3. Never obstruct the vent grilles, or any ducts that pro-
vide air to the unit. Air must be provided for proper com-
bustion and ventilation of flue gases.
FreezingTemperaturesand YourStructure
Freeze warning.
Turn off water system.
If your unit remains shut off during cold weather
the water pipes could freeze and burst, resulting
in serious water damage.
Your unit is equipped with safety devices that may keep it from op-
erating if sensors detect abnormal conditions such as clogged ex-
haust flues.
If your unit remains shut off during cold weather the water pipes
could freeze and burst, resulting in serious water damage.
Ifthe structure will be unattended during cold weather you should
take these precautions.
1. Turn off main supply water into the structure and drain the
water lines if possible. Open faucets in appropriate areas.
2. Have someone check the structure frequently during cold
weather to make sure it is warm enough to prevent pipes
from freezing. Suggest they call qualified service agency, if
required.
Winter Shutdown
If you go away during the winter months and do not leave the heat
on in your home, the plastic transition box and the condensate
44001 101100
traponthefurnacemustbeprotectedfromfreezedamage.(See
Figure8troughFigure15)
1. Disconnectthe5/8"ODrubberhosefromtheventdrainfit-
tingthatislocateddownstreamofthecombustionblower.
Insertafunnelintothehoseandpourfour(4)ouncesof
sanitarytype(RV)antifreezeintothecondensatetrap.Re-
connectthe5/8"ODrubberhosetothestubonthevent
drainfitting.Securewiththehoseclamp.
2. Installation
Poison carbon monoxide gas Hazard.
This furnace can NOT be common vented or
connected to any type B, BW or L vent or vent
connector, nor to any portion of a factory-built or
masonry chimney. If this furnace is replacing a
previously common-vented furnace, it may be
necessary to resize the existing vent and
chimney to prevent oversizing problems for the
other remaining appliance(s). See Venting and
Combustion Air Check in Gas Vent Installation
section. This furnace MUST be vented to the
outside.
Failure to properly vent this furnace or other
appliances can result in death, personal injury
and/or property damage.
2. Disconnect the 3/4" OD rubber hose from the condensate
trap. Insert a funnel into the hose and and pour four(4)
ounces of sanitary type (RV) antifreeze into the plastic
Transition box. Squeeze the hose together near the end
and quickly reconnect the 3/4" OD rubber hose to the stub
on the condensate trap. Secure with the hose clamp.
When you return home, your furnace will be ready to start, as it is
not necessary to drain the antifreeze from the furnace.
Typical Upflow Installation
AIuminumornon-rustingshietdrecommended.
(SeeVentTerminationShieldingfordimensions).
•8" Min. _ I_
20' Max. rq _ InletPipe Ooup%gonendsoi
atmospheric Single Pipe pipe& couplingout-
in same <_ (_ _-_ (notusedon exhaustpipe.Total
zone model) sidestructure= 8"
VentPipes MUSTbe
supported
Horizontallyand
Vertically
Min.
Max.
zone
LocationandClearances
Refer to Figure 1 or Figure 2 for typical installation and ba-
sic connecting parts required. Refer to Figure 4 for typical
horizontal direct vent installation and basic connecting
parts required. Supply and return air plenums and duct are
also required.
If furnace is a replacement, it is usually best to install the
furnace where the old one was. Choose the location or
evaluate the existing location based upon the minimum
clearance and furnace dimensions (Figure 3).
CAUTION
Special precautions MUST be made if installing
furnace in an area which may drop below freezing. This
can cause improper operation or damage to
equipment. Iffurnace environment has the potential of
freezing, the drain trap and drainline must be
protected. The use of electric heat tape or RV
antifreeze is recommended for these installations.
(See "Condensate Trap Freeze Protection Section")
* Increaseminimumfrom8" to 18" forcold climates (sustainedtemperatures
below0 oF). 25-23-33
Typical Downflow Installation
SeeVentTermination
ShieldinginVentSection.
I_ "8" Min.
Inlet Pipe _ _] 20' Max.
(notusedon_H in same
single pip-_(_ c_) atmospheric zone
model)
Vent PipesMUSTb
supportedHorizonta
andVertically
\_ _ "////_/////////Y////_
Couplingon inside
andoutsideofwait
torestrainventpipe
Min.
Max.
same
Do NOT operate furnace in a corrosive atmosphere
containing chlorine, fluorine or any other damaging
chemicals. Refer to Combustion & Ventilation Air
section, Contaminated Combustion Air.
44001 1011O0
* Increaseminimumfrom8" to 18" for coldclimates(sustainedtemperatures
below0°F).
25-23-33a
Dimensions and Clearances
I
I
!
_1 Models)
TOP
-4E_ 1
LEFT SIDE F_
TRAP (DOWNFLOW)_
• T.EOMOSTAT_ ___
4
I "4
17/8
215/8 1 47/8
/ 24
BOTTOM
291_8 _=_ 37/8
Unit
Capacity
NgMP1050B12A
NgMP1075B12A
NgMP1080F16A
N9MP1100F14A
N9MPl100J20A
N9MPl125J20A
N9MP2050B12A
N9MP2075B12A
N9MP2080F16A
N9MP2100F14A
N9MP2100J20A
N9MP2125J20A
*9MPD050F12A
*9MPD075F12A
*9MPD080J16A
*9MPD100J14A
*9MPD100J20A
*9MPD125L20A
Cabinet Bottom
F _ AIR INTAKE (N9MP2 &*gMPD
VN'NT,_MPDM°d.,°°°
1
11,,4
1318 / 2 3/4
175/16 / 2! 7,,8
241/1/ 1913,'16
1
D
125/8
125/8
143/4
143/4
183/4
183/4
125/8
125/8
143/4
143/4
183/4
183/4
143/4
143/4
183/4
183/4
183/4
23
1311/16
A
B--
FRONT
113,,16
93 /8
1913/16 27
Cabinet to Combustible Clearances
TOPBOT.RB FRONTFL E
1 0 0 0 0 3 0
281/2
-- I_ 181/2
/
RIGHT SIDE
TRAP (DOWNFLOW)
© ELECTRICAL
(ALTERNATE)
VENT
TRAP
(UPFLOW/HORiZONTAL)
THERMOSTAT 21/4 •
131/4
215/8
24
ALL DIMENSIONS IN INCHES
17/8
25-23-36A
[_ 44001 101100
InstallationRequirements
1. Install furnace level.
2. This furnace is NOT to be used for temporary heat of build-
ings or structures under construction.
3. Install furnace as centralized as practical with respect to the
heat distribution system.
4. Install the vent pipes as short as practical. (See Vent and
Combustion Air Piping section).
5. Maintain clearance for fire safety and servicing. A front
clearance of 30" is recommended for access to the burner,
controls and filter.
6. Use a raised base for upflow furnace if the floor is damp or
wet at times.
For downflow installations, non combustible subbase must
be used under the furnace unless installation is on a non
combustible floor surface. This requirement applies even
when a coi! box or cabinet is used.
Fire Hazard.
Place furnace on noncombustible subbase on
downflow applications, unless installing on
non-combustible flooring.
Failure to install unit on noncombustible
subbase can result in death, personal injury
and/or property damage.
For horizontal installations, line contact is permissible only
between lines formed by intersection of back and two sides
of furnace jacket, and building joists, studs or framing.
9.
Residential garage installations require:
Burners and ignition sources installed at least 18" above
the floor.
• Located or physically protected from possible damage
by a vehicle.
10. Local codes may require a drain pan under the entire fur-
nace and condensate trap when the furnace is installed in
attic application.
InstallationPositions
This furnace can be installed in an upflow, horizontal (either left or
right) or downflow airflow position. DO NOT install this furnace on
its back. For the upflow position, the return air ductwork can be
attached to either the left or right side panel and/or the bottom. For
horizontal and downflow positions, the return air ductwork must
be attached to the bottom. The return air ductwork must never be
attached to the back of the furnace.
quired for the condensate trap. Downward slope of the conden-
sate drain line from the condensate trap to the drain location must
be provided. Adequate freeze protection of the drain trap and the
drain line must be provided. See "Condensate Drain Trap"section
for further details.
Leveling
Proper leveling of the furnace must be provided to insure proper
drainage of the condensate from the furnace. The furnace must
be level to within 1/4" from front to back and from side to side for
upflow and downflow installations or top to bottom for horizontal
installations.
Vent and Combustion Air Connections
On the Dual Certified furnace, the vent and combustion air pipes
attach to the furnace through the top panel for the upflow and hori-
zontal installations. For the downflow installation, the vent and
combustion air pipes attach to the furnace through the alternate
locations on the furnace side panels.
Note: On the Direct Vent furnace, the vent pipe attaches to the fur-
nace through the side panels. The combustion air pipe attaches to
the top panel or to the alternate location on the side panel.
On the Single Pipe furnace, the vent pipe attaches to the furnace
through the furnace side panels.
Note: Repositioning of the combustion blower is required for the
vent pipe connection to the furnace through the "right side" panel.
See "Vent and Combustion Air Piping" section for further details.
HorizontalFurnaceInstallation
This furnace can be installed horizontally in an attic, basement,
crawl space, alcove, or suspended from a ceiling in a basement or
utility room. See Figure 4. Do not install furnace on its back or in
the reverse airflow positions as safety control operation will be ad-
versely affected.
Typical Horizontal Installation
Inlet Pipe (notusedonSinglePipemodel)
Vent
Pipe
Condensate
Trap
FurnaceInstallationConsiderations
The installation of the furnace for a given application will dictate
the position of the furnace, the airflow, ductwork connections,
vent and combustion air piping. Consideration must be given to
the following:
CondensateTrap and Drain Lines
The supplied condensate trap must be attached to the furnace
side panel on either the left or right side. For horizontal installa-
tions, the drain trap is vertically attached to the side panel below
the furnace. A minimum clearance of 6" below the furnace is re-
44001 1011O0
25-23-34
NOTE: 5" bottom clearance required for condensate trap.
If the furnace is to be suspended from the floor joists in a crawl
space or the rafters in an attic, it is necessary to use steel pipe
straps or an angle iron frame to rigidly attach the furnace to pre-
vent movement. These straps should be attached to the furnace
with sheet metal screws and to the rafters or joists with bolts. The
preferred method is to use an angle iron frame bolted to the rafters
or joists. (Take caution to allow door panels to be removed for
maintenance)
Ifthefurnaceistobeinstalledinacrawlspace,consultlocal
codes.Asuitableconcretepadorblocksarerecommendedfor
crawlspaceinstallationontheground.
NOTE:6"bottomclearancerequiredforcondensatetrap.
Thirty(30)inchesbetweenthefrontofthefurnaceandadjacent
constructionorotherappliancesMUSTbemaintainedforservice
clearance.
Keep all insulating materials clear from Iouvered door. Insulating
materials may be combustible.
3. Combustion & Ventilation Air
Poison carbon monoxide gas Hazard.
Use methods described here to provide
combustion and ventilation air.
Failure to provide adequate combustion and
ventilation air can result in death and/or
personal injury.
Ventingand CombustionAir Check
NOTE: The following information is supplied to allow the installer
to make adjustments to the setup of existing appliances, IF
REQUIRED, based on good trade practices, local codes, and
good judgement of the installer. Manufacturer does NOT take re-
sponsibility for modifications made to existing equipment.
NOTE: If this installation replaces an existing furnace from a
commonly vented system, make sure there is adequate combus-
tion air for all appliances, MAKE THE FOLLOWING CHECK.
1. Seal any unused openings in the venting system.
Visually inspect the venting system for proper size and hor-
izontal pitch to ensure there is no blockage or restriction,
leakage, corrosion or other deficiencies which could cause
an unsafe condition.
Insofar as is practical, close all doors and windows and all
doors between the space in which the appliance(s) remain-
ing connected to the venting system are located and other
spaces of the building.
Turn on clothes dryers and any appliance not connected to
the venting system. Turn on any exhaust fans, such as
range hoods and bathroom exhausts, so they will operate
at maximum speed. Do not operate a summer exhaust fan.
Close fireplace dampers.
Followthe lighting instructions for each appliance being in-
spected. Adjust thermostat so appliance(s) will operate
continuously.
Allow 5 minutes of main burner operation, then check for
spillage at the draft hood relief opening of each appliance.
Use the flame of a match or candle (Figure 5).
G3
The horizontal furnaces may be installed directly on combustible
wood flooring or supports as long as all required furnace clear-
ances are met. See Figure 3.
This furnace MUST NOT be installed directly on carpeting or tile
or other combustible material other than wood flooring or sup-
ports.
For horizontal installation over a finished living space. A field fab-
ricated auxiliary drain pan with drain pipe is recommended to pre-
vent damage by overflow due to blocked condensate drain.
Vent Check
Vent Pipe--_ I A/ Draft Hood
Typical Gas
WaterHeater / Matc.
I I
I 1
7. After it has been determined that each appliance vents
properly, return doors, windows, appliances etc. to their
normal condition.
8. If improper venting is observed, the cause MUST be cor-
rected using the appropriate tables in code books of coun-
try having jurisdiction.
NOTE: if flame pulls towards draft hood, this indicates sufficient
venting.
NOTE: Non direct vent appliances occupying same enclosed
space as furnace MUST have enough air for proper combustion
and ventilation. All duct or openings for supplying combustion and
ventilation air must comply with the gas and electrical codes of the
country having jurisdiction.
When the installation is complete, check that all appliances have
adequate combustion air and are venting properly. See Venting
And Combustion Air Check in this manual.
Air Openingsand ConnectingDucts
1. Total input rating for all non direct vent gas appliances
MUST be considered when determining free area of open-
ings.
2. Connect ducts or openings directly to outside.
3. When screens are used to cover openings, they MUST be
no less than 1/4" mesh.
4. The minimum dimension of rectangular air ducts MUST
NOT be less than 3".
5. When sizing grille or louver, use the free area of opening. If
free area is NOT stamped or marked on grill or louver, as-
sume a 20% free area for wood and 60% for metal.
Confined SpaceInstallation
NOTE: A confined space is defined as an area with less than 50
cubic feet per 1,000 BTUH input rating for all gas appliances
installed in the area.
Requirements
1. Provide confined space with sufficient air for proper com-
bustion and ventilation of flue gases using horizontal or
vertical ducts or openings.
44001 101100
Figure 6 illustrate how to provide combustion and ventila-
tion air. A minimum of two permanent openings, one inlet
and one outlet, are required.
3,
One opening MUST be within 12" of the floor and the se-
cond opening within 12" of the ceiling.
4.
Size openings and ducts per Table 1.
Outside Air (This is ONLY a guide. Subject to codes of country having jurisdiction.)
ThisinstallationNOTapprovedinCanada
GableVent_b.J
= OptionalInlet Air (t)
I II I -- i
SoffitVent
_Air (t)
wate_
5. Horizontal duct openings require 1" square offree area per
2,000 BTUH of combined input for all gas appliances in
area (see Table 1).
6. Vertical duct openings or openings directly to outside re-
quire 1" square of free area per 4,000 BTUH for combined
input of all gas appliances in area (see Table 1).
Gable Vent
Air (t)
Inlet
Air (t]
Soffit Vent
MinimumOne Inlet and One OutletAir Supply is Required
InletAir Opening Must beWithin12"of floor
OutletAir OpeningMustbeWithin12" of ceiling
(t) t SquareInch per4000 BTUH
(2)t SquareInch per2000 BTUH
May beinandCombinationShown
Inlet
Air(t)
Free Area
MinimumFreeAreaRequiredfor EachOpening
BTUH
input HorizontalDuct
Rating (2,000 BTUH)
50,000 25 sq.in.
75,000 37.5sq. in.
100,000 50 sq.in.
125,000 62.5sq. in.
150,000 75 sq. in.
EXAMPLE: Determining Free Area
Appliance 1 Appliance 2 Total Input
100,000 + 30,000 = (130,000 + 4,000) = 32.5 Sq. In. Vertical
Appliance 1 Appliance 2 Total Input
100,000 + 30,000 = (130,000 + 2,000) = 65 Sq. In. Horizontal
VerticalDuctoropenings Round
to outside Duct
(4,000BTUH) (4,000
12.5sq.in. 4"
18.75sq. in. 5"
25sq. in. 6"
31.25sq, in. 7"
37.5sq. in. 7"
BTUH)
Inlet
Air (2)
UnconfinedSpaceInstallation
Poison carbon monoxide gas Hazard,
Most homes will require additional air.
An unconfined space or homes with tight
construction may not have adequate air
infiltration for proper combustion and ventilation
of flue gases.
Failure to supply additional air by means of
ventilation grilles or ducts could result in death
and/or personal injury.
An unconfined space is defined as an area having a minimum vol-
ume of 50 cubic feet per 1,000 Btuh total input rating for all gas
appliances in area. Refer to Table 2 for minimum area required.
One permanent opening, commencing within 12" of the top of the
enclosure, shall be permitted where the equipment has clear-
ances of at least 1" from the sides and back and 6" from the front
of the appliance. The opening shall directly communicate with the
outdoors or shall communicate through a vertical or horizontal
duct to the outdoors or spaces (crawl or attic) that freely communi-
cate with the outdoors, and shall have a minimum free area of:
• 1sq. in per 3000 Btu per hr. of the total input rating of all
equipment located in the enclosure, and
• Not less than the sum of the areas of all vent connectors
in the confined space.
44001 1011O0
Unconfined Space
Minimum Area in Square Feet
BTUH Input Minimum Area in Square Feet
Rating
50,000 312
78,000 490
114,000 712
155,000 968
EXAMPLE: NOTE: Square feet is based on 8 foot ceilings,
28,000BTUH X 50CubicFt. = 1,400 = 175Sq. Ft.
1,000 8' Ceiling Height
NOTE:Referto definitionsin sectiontitledUnusually Tight
Construction. If any one of the conditions apply, the space MUST
be considered confined space regardless of size.
1. Adjoining rooms can be considered part of an unconfined
area if there are openings without doors between rooms.
2. An attic or crawl space may be considered an unconfined
space provided there are adequate ventilation openings di-
rectly to outdoors. Openings MUST remain open and NOT
have any means of being closed off. Ventilation openings to
outdoors MUST be at least 1" square of free area per 4,000
BTUH of total input rating for all gas appliances in area.
3. Install air intake a minimum of 12" above maximum snow
level and clear of any obstruction. Duct or ventilation open-
ing requires one square inch of free area per 4,000 BTUH
of total input rating for all gas appliances in area.
4. Air inlet MUST be screened with not less than 1/4" mesh
screen.
UnusuallyTight Construction
In unconfined spaces, infiltration may be adequate to provide air
for combustion, ventilation and dilution of flue gases. However, in
4. Vent and Combustion Air Piping
buildings with unusually tight construction, additional air MUST
be provided using the methods described in section titled Con-
fined Space Installation:
Unusually tight construction is defined as: Construction with
Walls and ceilings exposed to the outside have a continu-
ous, sealed vapor barrier. Openings are gasketed or
sealed and
2.
Doors and openable windows are weather stripped and
3.
Other openings are caulked or sealed. These include joints
around window and door frames, between sole plates and
floors, between wall-ceiling joints, between wall panels, at
penetrations for plumbing, electrical and gas lines, etc.
VentilationAir
Some provincial codes and local municipalities require ventilation
or make-up air be brought into the conditioned space as replace-
ment air. Whichever method is used, the mixed return air temper-
ature across the heat exchanger MUST not fall below 60 °F or flue
gases will condense in the heat exchanger. This will shorten the
life of the heat exchanger and possibly void your warranty.
Contaminated Combustion Air
Poison carbon monoxide gas, fire and explo-
sion hazard,
Read and follow all instructions in this section,
Failure to properly vent this furnace can result in
death, personal injury and/or property damage.
SinglePipe(NgMP1Models)
This furnace is certified as a category IV appliance. This furnace
requires ventilation openings to provide air for proper combustion
and ventilation of flue gases. All duct or openings for supplying
combustion and ventilation air must comply with the gas codes or
in absence of local codes, the applicable national codes.
When the installation is complete, see the "Venting and Com-
bustion Air Check" in this manual.
DirectVent(NgMP2Models)
This furnace is certified as a category IV appliance. This furnace
uses outside air for combustion ONLY, it MUST be taken from the
same atmospheric pressure zone as the vent pipe. See Con-
fined Space Installation in the Combustion and Ventilation
Air in this manual.
DualCertified (*9MPDModels)
This furnace is certified as a category IV appliance. This furnace
can be installed as a direct vent furnace using outside air for com-
bustion or the furnace can use air from inside the structure for
combustion. The INLET air pipe is optional. If combustion air
comes from inside the structure, adequate make up air MUST be
provided to compensate for oxygen burned. See Confined
Space Installation in the Combustion and Ventilation Air
chapter, if combustion air is drawn from outside the structure, it
MUST be taken from the same atmospheric pressure zone as the
vent pipe.
Installations in certain areas or types of structures will increase
the exposure to chemicals or halogens that may harm the fur-
nace.
The following areas or types of structures may contain or have ex-
posure to the substances listed below. The installation must be
evaluated carefully as it may be necessary to provide outside air
for combustion.
• Commercial buildings.
• Buildings with indoor pools.
• Furnaces installed in laundry rooms.
• Furnaces installed in hobby or craft rooms.
• Furnaces installed near chemical storage areas.
• Permanent wave solutions for hair.
• Chlorinated waxes and cleaners.
• Chlorine based swimming pool chemicals.
• Water softening chemicals.
• De-icing salts or chemicals.
• Carbon tetrach!oride.
• Halogen type refrigerants.
• Cleaning solvents (such as perch!oroethylene).
• Printing inks, paint removers, varnishes, etc.
• Hydrochloric acid.
• Sulfuric Acid.
• Solvent cements and glues.
• Antistatic fabric softeners for clothes dryers.
• Masonry acid washing materials.
Ventand Combustion Air PipingGuidelines
NOTE: All vent piping MUST be installed in compliance with local
codes or ordinances, these instructions, good trade practices,
and codes of country having jurisdiction.
44001 1011oo
1. Determinethebestroutingandterminationforthevent
pipeandairinletpipebyreferringtoalloftheinstructions
andguidelinesinthisSection.
2. Determinethesizerequiredfortheventpipeandairinlet
pipe.
3. Looselyassembleallventingpartswithoutadhesive(pipe
jointcement)forcorrectfitbeforefinalassembly.
4. Useofverticalpipingispreferredbecausetherewillbe
somemoistureinthefluegasesthatmaycondenseasit
leavestheventpipe(SeeSpecial Instruction For Horizon-
tal Vents).
5. The vertical vent pipe MUST be supported so that no
weight is allowed to rest on the combustion blower.
6. Exhaust vent piping or air inlet piping diameter MUST NOT
be reduced.
7. All exhaust vent piping from the furnace to termination
MUST slope upwards. A minimum of 1/4" per foot of run is
required to properly return condensate to the furnace drain
system.
8. Use DWV type long radius elbows whenever possible, as
they provide for the minimum slope on horizontal runs and
they provide less resistance in the vent system. If DWV el-
bows cannot be used, use two, 45 ° elbows when possible.
On horizontal runs the elbows can be slightly misaligned to
provide the correct slope.
9. All horizontal pipe runs MUST be supported at least every
five feet with galvanized strap or other rust resistant materi-
al. NO sags or dips are permitted.
10. All vertical pipe runs MUST be supported every six feet
where accessible.
11. The minimum pipe run length is 2'.
12. The piping can be run in the same chase or adjacent to sup-
ply or vent pipe for water supply or waste plumbing. It can
also be run in the same chase with a vent from another 90+
furnace.
NOTE: In NO case can the piping be run in a chase where
temperatures can exceed 140 ° R or where radiated heat
from adjacent surfaces would exceed 140 ° F.
13. The vent outlet MUST be installed to terminate in the same
atmospheric pressure zone as the combustion air inlet.
14. The vent system can be installed in an existing unused
chimney provided that:
• Both the exhaust vent and air intake run the length ofthe
chimney.
• No other gas fired appliance or fireplace (solid fuel) is
vented into the chimney.
• The top of the chimney MUST be sealed flush or
crowned up to seal against rain or melting snow so ONLY
the piping protrudes.
• The termination clearances shown in Figure 7 are main-
tained.
15. Furnace applications with vertical vents requiring vent di-
ameter increaser fittings muet have increaser fittings
installed in vertical portion of the vent. Condensate will be
trapped in the vent if the vent diameter is increased prior to
having an elbow turned upward. This could cause nui-
sance tripping of the pressure switch.
PipingInsulation Guidelines
NOTE: Use closed cell, neoprene insulation or equivalent. If Fi-
berglass or equivalent insulation is used it must have a vapor bar-
rier. Use R values of 7 up to 10', R- 11 if exposure exceeds 10'. If
Fiberglass insulation is used, exterior to the structure, the pipe
MUST be boxed in and sealed against moisture.
1. When the vent or combustion air pipe height above the roof
exceeds 30", or if an exterior vertical riser is used on a hori-
zontal vent to get above snow levels, the exterior portion
MUST be insulated.
2. When combustion air inlet piping is installed above a sus-
pended ceiling, the pipe MUST be insulated with moisture
resistant insulation such as Armaflex or other equivalent
type of insulation.
3. Insulate combustion air inlet piping when run in warm, hu-
mid spaces such as basements.
Sizing CombustionAir and Vent Pipe
Consult Table 3 or Table 4 to select the proper diameter exhaust
and combustion air piping. Exhaust and combustion air piping is
sized for each furnace Btuh size based on total lineal vent length
(on inlet or outlet side), and number of 90 ° elbows required. Two
45 °elbows can be substituted for one 90 ° elbow. The elbow or el-
bows used for vent termination outside the structure ARE
counted, including elbows needed to bring termination above ex-
pected snow levels.
Pipe Diameter Table
N9MP1 & *gMPD Models
50,000, 75,000 & 80,000 Btuh Furnaces
40' & (5) 90 ° elbows with 2" PVC pipe or
70' & (5) 90 ° elbows with 3" PVC pipe
100,000 Btuh Furnace
40' & (5) 90 ° elbows with 3" PVC pipe or
70' & (5) 90° elbows with 3" PVC pipe &
Long Vent Kit (See Tech. Manual)
125,000 Btuh Furnace
40' & (5) 90 ° elbows with 3" PVC pipe
Elbows are DWV Long Radius Type for 2" and 3" vents.
If more than five elbows are required, reduce the length of
both the inlet and exhaust pipes 5' for each additional elbow
used.
NOTE: it is allowable to use larger diameter pipe and fitting than
shown in the tables but not smaller diameters than shown.
Pipe Diameter Table
N9MP2 Models
50,000 & 80,000 Btuh Furnaces
40' & (5) 90 ° elbows with 2" PVC pipe or
70' & (5) 90 ° elbows with 3" PVC pipe
75,000 Btuh Furnaces
25' & (3) 90 ° elbows with 2" PVC pipe or
40' & (5) 90 ° elbows with 2" PVC pipe &
Long Vent Kit (See Tech, Manual) or
70' & (5) 90 ° elbows with 3" PVC pipe
100,000 Btuh Furnace
40' & (5) 90 ° elbows with 3" PVC pipe or
70' & (5) 90 ° elbows with 3" PVC pipe &
Long Vent Kit (See Tech. Manual)
125,000 Btuh Furnace
40' & (5) 90 ° elbows with 3" PVC pipe
Elbows are DWV Long Radius Type for 2" and 3" vents.
If more than five elbows are required, reduce the length of
both the inlet and exhaust pipes 5' for each additional elbow
used.
For "Concentric Termination Kit" Venting table, see
"Section 10" in this manual.
44001 101100
VentTermination Clearances
Poison carbon monoxide gas, fire and explo-
sion hazard.
Inlet and outlet pipes may NOT be vented
directly above each other.
Failure to properly vent this furnace can result in
death, personal injury and/or property damage.
1. Determinetermination locations based on clearances spe-
cified in following steps and as shown in Figure 7,
Figure 17, through Figure 25,
For "Concentric Termination Kit" clearances, see Figure 43,
Figure 44, Figure 45, Figure 46and Figure 47 in "Section 10"
in this manual.
2. The vent termination must be located at least 12" above
ground or normally expected snow accumulation levels.
3. Do NOT terminate over public walkways. Avoid areas
where condensate may cause problems such as above
planters, patios, or adjacent to windows where steam may
cause fogging.
4. The venttermination shall be located at least 4' horizontally
from any electric meter, gas meter, regulator, and any relief
equipment. These distances apply ONLY to U.S. installa-
tions.
The vent termination is to be located at least 3' above any
forced air inlet located within 10' ; and at least 10' from a
combustion air intake of another appliance, except another
direct vent furnace intake.
6. In Canada, the Canadian Fuel Gas Code takes prece-
dence over the preceding termination instructions.
Vent Termination Clearances
(United States Only)
In Canada See Canadian Fuel Gas Code
OtherThan
0ther Than
DirectVent
Terminal
CondensateDrainTrap
This furnace removes both sensible and latent heat from the prod-
ucts of combustion. Removal of the latent heat results in con-
densation of the water vapor. The condensate is removed from
the furnace through the drains in the plastic transition and the vent
fitting. The drains connect to the externally mounted condensate
drain trap on the left or right side of the furnace.
The condensate drain trap supplied with the furnace MUST be
used. The drain connection on the condensate drain trap is sized
for 3/4" PVC or CPVC pipe. Alternate drain pipes and hoses may
be used as allowed by local codes.
The drain line must maintain a 1/4" per foot downward slope to-
ward the drain.
DO NOT trap the drain line in any other location than at the con-
densate drain trap supplied with the furnace.
Frozen water pipe hazard.
When activated an auxiliary safety switch will
cause a furnace not to operate.
During freezing temperatures the water pipes in
your home could freeze and burst causing water
damage to the home.
Do not leave the home unattended during freezing
temperatures, or shut off the water supply and
drain the pipes before leaving.
If possible DO NOT route the drain line where it may freeze. The
drain line must terminate at an inside drain to prevent freezing of
the condensate and possible property damage.
1. A condensate sump pump MUST be used if required by lo-
cal codes, or if no indoor floor drain is available. The con-
densate pump must be approved for use with acidic
condensate.
2. A plugged condensate drain line or a failed condensate
pump will allow condensate to spill. If the furnace is
installed where a condensate spill could cause damage, it
is recommended that an auxiliary safety switch be installed
to prevent operation of the equipment in the event of pump
failure or plugged drain line. If used, an auxiliary safety
switch should be installed in the R circuit (low voltage)
ONLY.
CondensateDrainTrapFreezeProtection
DirectVent
Terminal
50,000Btuh
orless
OtherThan
Direct Vent Forced Air
Terminal 12" Inlet
DirectVentTerminal
MoreThan 50,000 Btuh
[_ 44001 101100
10-11-36
Special precautions MUST be made if installing furnace in an
area which may drop below freezing. This can cause improper op-
eration or damage to the equipment. If the the furnace environ-
ment has the potential of freezing, the drain trap and drain line
must be protected. Use 3 to 6 watt per foot at 115 volt, 40 ° F self-
regulating shielded and waterproof heat tape. Wrap the drain trap
and drain line with the heat tape and secure with the ties. Follow
the heat tape manufacturer's recommendations.
Upflow Installations (Dual Certified *9MPD Models)
LEFT Side Venting RIGHT Side Ventina
Supply Air _ Vent Pipe
Vent Pipe
Vent Fittin_
Gas Pipe
90 ° Elbow
Rubber Coupling
&Clamps
5/8
Clamps
Combustion
Blower
Plastic
CondensateTrap 7
& Gasket
(Left or Right Side)
Drain Line
Plug
3/4" Hose Combustion
& Clamps Blower
Mounting
Screws (4)
25-23-53
Pipe (optional) lSupply Air
Coupling
Plastic Caps
Pressure Switch
Blower
Pressure Switch
Transition
Pressure Switch,
Transition
Box Vent Drain
Pressure Switch,
Transition
DRAIN SIDE VIEW"
_lamp
SomeModels
haveone
RigidPlastic
DrainTube
UpflowInstallations- (Dual Certified *9MPD) (See
Mount the condensate drain trap in a vertical position to either the
left or right side of the furnace using the two screws and gasket
that are provided. If needed, remove the hole plugs from the fur-
nace side panel and relocate to the open set of holes in the oppo-
site side panel. Drill two 7/64" diameter holes in the casing using
the condensate trap as the template.
Ensure that the vent fitting and the 90° elbow is securely attached
to the combustion blower using the rubber coupling and clamps.
Plug the right drain stub of the vent fitting with the rubber plug. Use
a blunt pointed screwdriver to push the plug into the stub.
For left side venting, remove vent fitting assembly from combus-
tion blower. Remove 90 ° elbow and rubber tubing from the vent
fitting by loosening the clamp on the vent fitting. Securely attach
vent fitting to combustion blower.
NOTE: The vent fitting MUST be installed with the airflow marking
arrow pointed toward the vent pipe, with the drain stub at a 20 ° to
30 ° downward slope.
This configuration allows left side venting from the furnace. If right
side venting is required, the combustion blower must be relocated
on the plastic transition box. Remove the four(4) screws that se-
cure the blower to the transition. Rotate the blower 180 ° and se-
cure with the four(4) screws. Use caution to not over tighten the
screws to prevent stripping out of the plastic mounting holes.
Figure8)
Plug the upper drain stub on the vent fitting with the rubber plug.
Use a blunt pointed screwdriver to push the plug into the stub.
For left side mounted condensate trap, connect the 3/4" OD rub-
ber hose with the 90 ° bend to the large drain stub on the conden-
sate trap and secure with a 3/4" clamp.
Route the hose to the d rain stub on the bottom of the plastic transi-
tion box. Cut off excess hose and discard. Connect the hose with
the 90 ° bend to the drain stub on the transition and secure with a
3/4" clamp.
For right side mounted condensate trap, the rigid plastic drain
tube MUST be used. Cut two 2" long sections from the 3/4" OD
rubber hose. Connect the plastic drain tube to the drain stub on
the bottom of the plastic transition box and to the stub on the con-
densate trap using the two hose sections and 3/4" clamps.
NOTE: The support leg on the plastic drain tube MUST be posi-
tioned on the blower partition.
Connect the 5/8" OD rubber hose with the 90 ° bend to the left
drain stub on the vent fitting and secure with a 5/8" clamp.
Route the hose to the small drain stub on the condensate trap. Cut
off excess hose and discard. Connect the hose to the drain stub
on the trap and secure with a 5/8" clamp.
NOTE: Ensure hoses maintain a downward slope to the conden-
sate trap with no kinking or binding for proper condensate drain-
age.
44001 1011O0 [_
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