Nordyne Furnace M3RL User Manual

Direct Vent (Sealed Combustion) Forced Air Gas Furnaces  
Installation Instructions  
M3RL Series 90+ Downflow Condensing Furnace  
Forinstallationin:  
1. Manufactured Homes  
2. ParkModelsandManufacturedBuildings  
3. ModularHomes/Buildings  
!
WARNING:  
FIRE OR EXPLOSION HAZARD  
Failure to follow safety warnings exactly could  
result in serious injury, death or property  
damage.  
– Do not store or use gasoline or other flammable  
vapors and liquids in the vicinity of this or any other  
appliance.  
– 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.  
• Leavethebuildingimmediately.  
• Immediatelycallyourgassupplierfromaneighbor's  
phone. Follow the gas supplier's instructions.  
• If you cannot reach your gas supplier, call the fire  
department.  
– Installation and service must be performed by a  
qualified installer, service agency, or the gas sup-  
plier.  
BW Models  
BWT Models  
!
ADVERTISSEMENT:  
RISQUE D’INCENDIE OU D’EXPLOSION  
Le non-respect des avertissements de sécurité  
pourrait entraîner des blessures graves, la  
mort ou des dommages matériels.  
!
WARNING:  
Should overheating occur, or the  
gas supply fail to shut off, shut  
off the manual gas valve to the  
appliance before shutting off the  
electrical supply.  
– Ne pas entreposer ni utiliser de l’essence ni  
d’autres vapeurs ou liquides inflammables dans le  
voisinage de cet appareil, ni de tout autre appareil.  
– QUE FAIRE S’IL Y A UNE ODEUR DE GAZ  
• Ne pas tenter d’allumer aucun appareil.  
• Ne toucher à aucun interrupteur électrique;  
n’utiliser aucun téléphone dans le bâtiment.  
• Évacuerl’immeubleimmédiatement.  
Improper installation, adjust-  
ment, alteration, service or  
maintenance can cause injury  
or property damage. Refer to  
this manual. For assistance or  
additional information consult  
a qualified installer, service  
agency or the gas supplier.  
• Appeler immédiatement le fournisseur de gaz en  
employant le téléphone d’un voisin. Respecter à  
la lettre les instructions du fournisseur de gaz.  
• Si personne ne répond, appeler le service des  
incendies.  
– L’installation et l’entretien doivent être effectués  
par un installateur qualifié, un organisme de  
service ou le fournisseur de gaz.  
LEAVE THESE INSTRUCTIONS WITH THE HOMEOWNER.  
 
TABLE OF CONTENTS  
General ...................................................... 4  
Conversion .............................................. 21  
UnitDimensions .................................. 4  
Shipping Weights................................ 4  
Furnace Specification ........................ 4  
Air Flow Data ..................................... 4  
LightingandAdjustment  
of the Appliance .............................. 23  
ElectricalWiring ...................................... 24  
LineVoltageWiring ........................... 24  
LowVoltageWiring ........................... 26  
Owner's Information ................................ 5  
Installation Requirements ...................... 6  
Location .............................................. 7  
Clearance ........................................... 7  
Ventilation ................................................ 26  
Start-up and Adjustment ........................ 26  
Start-UpProcedure ........................... 26  
Shut Down Procedure ....................... 27  
Verifying and Adjusting Firing Rate ... 27  
TemperatureRise ............................. 27  
VerifyingandAdjusting  
Circulating Air Supply ............................ 7  
Return Air Provisions.............................. 8  
Air Distribution Systems ........................ 9  
Duct Connector Selection .................... 10  
Duct Installation .................................... 10  
Verifying Burner Operation.............. 28  
Verifying Operation of the  
Supply Air Limit Switch ................. 28  
Venting and Combustion  
Description of Components ................ 29  
Air Requirements ........................... 13  
Furnace Accessories............................. 29  
Venting Requirements .......................... 14  
Vent Table ........................................ 15  
Vent Pipe Material ............................ 16  
Vent Pipe Length and Diameter ....... 16  
Vent Pipe Installation ........................ 16  
Pipe Routing & Support .................... 16  
Location of Outdoor Termination ..... 16  
Horizontal Venting ............................ 18  
Vertical Venting................................ 18  
Vent Freezing Protection ................. 19  
Concentric Vent Termination ........... 19  
Maintenance ........................................... 29  
Combustion Air and Vent System .... 29  
Air Filter(s) ....................................... 29  
Lubrication ........................................ 30  
Condensate Drain Assembly ........... 30  
Blower Compartment ....................... 30  
Heat Exchanger and Burner  
Maintenance .................................. 30  
System Operation Information............. 30  
Sequence of Operation .................... 30  
Furnace Fails to Operate ................. 31  
Drainage of Condensate  
From Furnace................................ 19  
Location of Major Components .......... 32  
Gas Supply and Piping ......................... 20  
Leak Check ....................................... 21  
High Altitude Derate ......................... 21  
Pressure Switch .............................. 21  
Wiring Diagram ....................................... 33  
Installation/Performance  
Checklist ......................................... 35  
M 3 R L - 060 A - A W  
Return Air Configuration  
Blank - Front  
T - Top  
Application  
M-Manufactured Home  
Door Color  
W - White  
G - Gray  
Furnace Series  
Cabinet Dimensions  
A - 56" x 19-3/4" x 23-3/4”  
B - w/Coil Cavity,  
Comfort Model  
RL - Condensing Downflow  
76" x 19-3/4" x 23-3/4"  
Electrical Code  
Heating Capacity  
A - 1PH, 60 Hz, 120 VAC  
Input, BTUH (000’)  
Table 1. Model Identification  
3
 
GENERAL  
1-1/2  
21-11/32  
COMBUSTIOON AIR INTAKE  
19-7/8  
3-17/32  
24-5/8  
COMBUSTION AIR INTAKE  
17-13/16  
EXHAUST VENT  
1-11/16  
EXHAUST  
VENT  
SIDE RETURN  
KNOCKOUTS  
SIDE RETURN  
KNOCKOUTS  
18-1/2  
18-1/2  
21-17/32  
21-29/32  
56-1/16  
7/8 Diameter  
(W/ Coiil Box)  
75-1/4  
(W/O Coiil Box)  
28-15/32  
23-7/16  
21-15/16  
20-9/32  
1-19/32  
3-17/32  
4-11/16  
1-19/32  
3-17/32  
4-11/16  
Cooling  
Coil  
19-3/16  
Box  
20-1/16  
24-3/4  
Figure 1. Furnace Dimensions  
TopReturnKnockouts  
12.000  
1.000  
Shipping  
Weight  
(lbs)  
Furnace Model  
M3RL 060A AW  
M3RL 060A BW*  
M3RL 080A AW  
M3RL 080A BW*  
* May include suffix - T  
21.000  
150  
170  
155  
175  
Top View  
(AW and BW Models)  
Top Return Opening  
(BWT Models)  
Table 2. Shipping Weight  
Furnace Specifications / Airflow Data  
Furnace Furnace Temp.  
External Static Pressure ( Inches Water Column) Recommended  
Furnace  
Model No.  
Input  
Btuh  
Output Rise @ Motor Motor  
0.1  
0.2  
0.3  
0.4  
0.5  
A/C  
Ton  
4
3
2.-1/2  
2
4
3
Btuh .3"WC °F HP  
Speed  
CFM  
1660  
1512  
1340  
1176  
1660  
1512  
1340  
1176  
CFM  
1599  
1467  
1304  
1142  
1599  
1467  
1304  
1142  
CFM  
1544  
1416  
1261  
1108  
1544  
1416  
1261  
1108  
CFM  
1474  
1363  
1217  
1025  
1474  
1363  
1217  
1025  
CFM  
1410  
1304  
1158  
966  
1410  
1304  
1158  
966  
High*  
Med-High  
Med-Low  
M3 RL-060 60,000  
54,000 35 - 65  
1/2 Low**  
High*  
Med-High  
Med-Low**  
2.-1/2  
2
M3 RL-080 80,000  
72,000 35 - 65  
1/2 Low  
Note: Data is for Operation with Filter.  
Factory Wired Cooling Tap  
** Factory Wired Heating Tap  
*
Table 3. Furnace Specifications/Airflow Data  
4
 
5. Never test for gas leaks with an open  
flame. Use a commercially available soap  
solution made specifically for the detection  
of leak to check all connections.  
6. Always install furnace to operate within the  
furnace’s intended temperature rise range  
with a duct system that has an external  
static pressure within the allowable range,  
as specified in page 4 of these instruc-  
tions. See furnace rating plate.  
7. When a furnace is installed so that supply  
ducts carry air circulated by the furnace to  
areas outside the space containing the  
furnace, the return air shall also be handled  
by duct(s) sealed to the furnace casing  
and terminating outside the space contain-  
ing the furnace. Note: This section only  
applies to furnaces installed with side or  
top return air.  
8. A gas-fired furnace for installation in a  
residential garage must be installed as  
specified in page 7 of these instructions.  
9. The furnace is not to be used for tempo-  
rary heat of buildings or structures under  
construction.  
!
WARNING:  
Do not use this appliance if any part  
hasbeensubmergedunderwater. Im-  
mediatelycallaqualifiedservicetech-  
nician to inspect the appliance and to  
replace any part of the control system  
and any gas control that has been  
submerged underwater.  
NOTICE TO INSTALLER  
Installer is advised to follow carefully all instruc-  
tions and warnings in this manual to insure  
maximum performance, safety, and operating  
efficiencyoftheseappliances.Improperinstalla-  
tion may create hazardous conditions, and will  
void the appliance warranty.  
GENERAL  
General Description  
The M3 series gas furnaces are listed direct  
vent (sealed combustion) forced air furnaces  
for use with both natural and propane gases.  
The M3 series is a Category IV and type FSP  
furnace. The M3 furnace series has been  
certified to the ANSI Z21.47/CSA2.3-2001 for  
use in the United States and Canada and to the  
UL307B —1995 for use in the United States.  
M3 series furnaces are air conditioning ready  
as shipped. The furnace cooling capacities of  
the blower motor speed taps are shown in  
Table 3. Table 2 lists the shipping weights for  
the M3 series furnaces.  
OWNER INFORMATION  
These furnaces may be installed in:  
1. Manufactured Homes.  
2. Park Models and Manufactured buildings  
3. ModularHomes/Buildings  
NORDYNE has been involved in the design of  
products for the manufactured home industry  
since the first manufactured home or trailer  
was built.  
The following are safety guidelines with refer-  
ences to their specific sections or pages in the  
manual.  
NORDYNE originated the sealed combustion  
system, which separates the furnace com-  
bustion system from the living area of the  
home, now a standard for the manufactured  
home industry.  
1. Use only type of gas approved for this  
furnace. Refer to the furnace rating plate.  
2. Install this furnace only in location and  
position as specified in pages 7 - 13 of  
these instructions.  
3. Provide adequate combustion and ventila-  
tion air to the furnace space as specified in  
pages 13 - 20 of these instructions.  
4. Combustion products must be discharged  
outdoors, connect this furnace to an ap-  
proved vent system only, as specified in  
pages 14-19 of these instructions.  
NORDYNE engineers developed the first cen-  
tral heating system and the first central air  
conditioner for manufactured homes.  
NORDYNE is dedicated to bringing to its cus-  
tomers the finest heating and cooling comfort  
possible. NORDYNE constantly seeks to fur-  
ther refine its products to continuously provide  
exceptional comfort.  
5
 
Follow the instructions in this booklet carefully  
and this appliance will provide many years of  
superior performance.  
6. Providing instructional training on how to  
light and operate the furnace.  
7. Furnace problems caused by installation of  
an air conditioner, heat pump or other air  
comfort devices.  
8. Revising installation of the furnace flue  
assembly.  
9. Adjusting or calibrating of thermostat.  
10. Any construction debris which falls into  
the flue system.  
If you wish to cool your home automatically  
with a central air conditioning system investi-  
gate the excellent NORDYNE cooling systems  
available from your heating and cooling con-  
tractor. These systems are designed to work  
best with your NORDYNE furnace and have  
been carefully engineered to deliver optimum  
performance when mated with NORDYNE  
manufactured home furnaces.  
Carefully review these responsibilities with your  
manufacturedhousingdealer,servicecompany  
or gas supplier so there will be no misunder-  
standing at a later time.  
NORDYNE also offers water heaters, fireplaces  
and ventilating systems specifically designed  
for manufactured housing applications. Check  
with your manufactured home retailer, your  
heating and cooling contractor or your  
distributor for information. Write directly to the  
factory (PO Box 8809, O’Fallon, MO 63366) if  
youarenotabletolocateasourceforNORDYNE  
manufactured housing products in your area.  
!
CAUTION:  
• Never attempt to alter or modify this  
furnace or any of its components.  
• Never attempt to repair damaged or  
inoperablecomponents.Suchaction  
could cause unsafe operation, ex-  
plosion, fireand/orasphyxiation.  
• If a malfunction has occurred, or if  
you feel that the furnace is not oper-  
atingasitshould,contactaqualified  
service agency or gas utility for as-  
sistance.  
MANUFACTURER WARRANTY, OWNER’S  
RESPONSIBILITIES  
It is the sole responsibility of the homeowner to  
makecertainthegasfurnacehasbeencorrectly  
set up and converted to the proper fuel (L.P. gas  
or Natural gas) and adjusted to operate prop-  
erly. All gas furnaces are manufactured for  
Natural gas and must be field converted when  
using L.P. gas.  
INSTALLATION STANDARDS  
Installershallbefamiliarwithandcomplywithall  
codes and regulations applicable to the installa-  
tion of these heating appliances and related  
equipment. In lieu of local codes, the installation  
shall be in accordance with the current provi-  
sions of one or more of the following standards.  
a. Federal Manufactured Home Constructions  
& Safety Standard (H.U.D. Title 24, Part  
3280.707[a][2])  
b. The Standard for Manufactured Home Instal-  
lations (Manufactured Home Sites, Commu-  
nities, and Set-Ups) ANSI A225.1 and/or  
CAN/CSA-2240 MH Series).  
c. American National Standard (ANSI-119.2/  
NFPA-501C) for all recreational vehicle in-  
stallations.  
d. American National Standard (ANSI-Z223.1/  
NFPA-54) and/or CAN/CGA B149 for all gas-  
fired furnace models.  
A warranty certificate with full details is included  
with these instructions. However, NORDYNE  
will not be responsible for any costs found nec-  
essary to correct problems due to improper  
setup,improperinstallation,furnaceadjustments,  
improper operating procedure on the part of the  
user, etc.  
Some specific examples of service calls which  
cannot be included in warranty payments are:  
1. Converting the furnace to use another type  
of gas.  
2. Repairing duct work in the home found to be  
faulty.  
3. Correcting wiring problems in the electrical  
circuit supplying the furnace.  
4. Resetting circuit breakers, blown fuses or  
other switches.  
e. AmericanNationalStandard(ANSI-C1/NFPA-  
70) and/or CSA 22.1 Canadian Electric Code  
Part 1 for all electrical field wiring.  
5. Correcting problems due to improper gas  
supply pressure to the furnace.  
6
 
CE générateur d'air chaud doit être installé  
conformément aux instructions du fabricant et  
aux codes locaux. En l'absence de code local,  
respecter la norme ANSI Z223.,1, institulé Na-  
tional Fuel Gas Code ou les codes d'installation  
CAN/GCA-B149.  
bustible material other than wood flooring. The  
furnace may be installed on combustible floor-  
ing when installed on a Nordyne duct connec-  
tor (see Table 5).  
The ductwork within 3 feet of the furnaces  
without the A/C coil box must be installed such  
that surfaces are at least 1/4" from combustible  
materials.  
The National Fuel Gas Code is available by  
writing:  
American National Standards Institute, Inc.  
1430 Broadway  
New York, NY 10018  
When installed in a residential garage, the fur-  
nace must be positioned so the burners and the  
source of the ignition are located no less than  
18 inches above the floor and protected from  
physical damage by vehicles.  
NFPA publications are available by writing:  
National Fire Protection Association  
Batterymarch Park  
Quincy, ME 02269  
CIRCULATING AIR SUPPLY  
LOCATION  
!
WARNING:  
The furnace must be installed on a level sur-  
face, and as close to the center of the air  
distribution system as possible. See Figure 1  
for overall dimensions to determine the re-  
quired clearances in hallways, doorways,  
stairs, etc. to allow the furnace to be moved to  
the installation point. The furnace must be in-  
stalled so that all electrical components are  
protected from water.  
Products of combustion must not be  
allowed to enter the return air openings  
of the furnace or the circulating air  
supply. Failure to prevent products of  
combustion from being circulated into  
the living space can create potentially  
hazardousconditionsincludingcarbon  
monoxidepoisoningthatcouldresultin  
personal injury or death.  
Minimum clearances to combustible materials  
are listed in Table 4. Access for positioning and  
servicing must be considered when locating  
the unit.  
The floor or platform on which the  
furnaceismountedmustprovidesound  
physical support of the furnace with no  
gaps, cracks, or sagging between the  
furnace and the floor or platform.  
This furnace is certified for use on wood  
flooring. The furnace must be installed on a  
solid surface and must be level front-to-back  
and side-to-side. This furnace must not be  
installed directly on carpeting, tile, or any com-  
The circulating air ductwork must not  
be connected to any other heat  
producing device such as a fireplace  
insert, stove, etc.  
CLOSET ALCOVE  
ALL MODELS  
Inches  
Inches  
Front  
Back  
Sides  
Vent  
Top  
Duct (Plenum)  
w/ Coil Box  
1*  
0
0
1*  
0
0
GENERAL  
0
6
0
6
Plenums and air ducts must be installed in  
accordance with the Standard for the Installa-  
tion of Air Conditioning and Ventilating Systems  
(NFPA No. 90A) or the Standard for the Instal-  
lation of Warm Air Heating and Air Conditioning  
Systems (NFPA No. 90B).  
0
1/4  
0
1/4  
w/o Coil Box  
(within 3 feet)  
*Note:For1clearance, useafullylouvereddoorwithat  
least400squareinchesoffreeairflowarea.  
Table 4. Minimum Clearances  
7
 
inthefloororceilingshallnotbelessthan235  
square inches.  
RETURNAIRPROVISIONS  
U.S.A. home manufacturers shall comply with  
all of the following conditions to have accept-  
able return air systems for closet installed  
forced air heating appliances:  
a. Regardless of the location, the return air  
opening into the closet shall not be less than  
specified in the appliance’s listing.  
b. Means shall be provided to prevent inadvert-  
ent closure by a flat object placed over the  
return air opening when it is located in the  
floor of the closet (versus the vertical front  
or side wall).  
c. Closet installations must use a louvered  
door having a minimum free area of 235 sq.  
in. when located 6” from furnace. For clear-  
ance between 1” and 6” from furnace, re-  
quirements are a louvered door with mini-  
mum of 235 sq. in. free area, with the open-  
ings in closet door directly inline with the  
louvered openings in the furnace door. For  
1” clearance from furnace, use a fully lou-  
vered door with at least 400 sq. in. of free  
airflow area.  
e. The total free area of openings in the floor or  
ceiling registers serving the return air duct  
system must be at least 352 sq. in. At least  
one register should be located where it is not  
likely to be covered by carpeting, boxes and  
other objects.  
f. Materials located in the return duct system  
must have a flame spread classification of  
200 or less. This includes a closet door if the  
furnace is in a closet.  
g. Noncombustible pans having 1" upturned  
flanges are located beneath openings in a  
floor duct system.  
h. Wiring materials located in the return duct  
system shall conform to Articles 300-22 of  
the National Electrical Code (ANSI C1/  
NFPA-70).  
19”  
TopView  
13 1/4"  
d. The cross-sectional area of the return duct  
system leading into the closet, when located  
of Duct  
10 1/4"  
Connector  
A Single trunk duct  
Figure 4.  
Use Duct Connector  
If "X" (Floor Cavity) is:  
English Metric (mm) Finger Tab Screw Down  
Model Part Number:  
Dual trunk duct  
B
w/crossover connector  
7/8"  
2"  
22  
51  
901987  
901988  
901989  
901990  
901991  
901992  
901993  
904008  
904009  
904010  
904011  
904012  
904013  
904014  
4 1/4"  
6 1/4"  
8 1/4"  
10 1/4"  
12 1/4"  
108  
150  
210  
260  
311  
Transition duct  
w/branches  
C
Figure 2. Non-Platinum  
Supply Duct System  
Table 5. Duct Connectors  
FLOOR CAVITY  
(depth equal to "X" in Figure 5 and Table 5)  
x
SUPPLY AIR DUCT  
Figure 3.  
8
 
( )OPENING TO DUCT  
REDUCER  
(1) WITH PLATE (C) REMOVED  
OPENING BECOMES  
13-1/4” x 13-1/4”  
FELT-SEAL(1)  
(2) WITH PLATE (C) REMOVED  
OPENING BECOMES  
13" X 13". WITH REDUCER  
IT IS 13" X 10-1/8".  
C
SEE  
X
TABLE 5  
SPACERS  
(1) FINGER TAB DUCT CONNECTOR ONLY  
(2) SCREW DOWN DUCT CONNECTOR ONLY  
Figure 5.  
ALT. FUEL  
LINE HOLES  
10"  
C
L
C
L
FLOOR  
OPENING  
23 -1/4"  
FUEL LINE  
HOLE  
Figure 6. Closet or Alcove  
tain necessary airflow. Use NORDYNE’s  
certiduct program to determine proper duct  
size for A/C.  
i. Gas piping is not run in or through the return  
duct system.  
j. Test the negative pressure in the closet with  
the air-circulating fan operating at high speed  
and the closet closed. The negative  
pressure is to be no more negative than  
minus 0.05 inch water column.  
k. For floor return systems, the manufactured  
home manufacturer shall affix a prominent  
marking on or near the appliance where it  
can be easily read when the closet door is  
open. The marking shall read:  
DUCTED RETURN AIR  
M3 furnaces with model numbers ending in AW  
or BW are factory configured for the return air  
to flow through the front louvered door. The  
return air may also be attached to either side or  
the top of the furnace cabinet using a field  
installedkit. RefertoTable12fortheNORDYNE  
ducted return kit P/N number. The location and  
size of the side and top return air connections  
are shown in Figure 1. The filter size for the side  
return air is 20” x 20” x 1”. For top return the  
filter size is 24” x 16” x 1”.  
!
CAUTION:  
HAZARD OF ASPHYXIATION: Do not  
cover or restrict return air opening.  
M3 furnaces with model numbers ending in  
BWT are factory configured for the return air to  
enter the top of the furnace.  
l. Air conditioning systems may require more  
duct register and open louver area to ob-  
9
 
20  
14-1/2  
2-3/4  
REAR WALL OF CLOSET OR ALCOVE  
2-1/4  
FLOOR CUT-OUT  
FOR DUCT CONNECTIONS  
17-29/32  
14-1/2  
21-3/4  
24  
21-7/16  
3-19/32  
1-3/4  
VENT  
23-1/4  
COMBUSTION AIR INTAKE  
FUEL LINE ENTRY  
2
10  
1-3/4  
˚
1-1/4  
12-7/8  
ALT FUEL LINE  
ENTRY  
14-3/4  
FURNACE  
OUTER DOOR  
15-1/2  
FLOOR CUT-OUT  
FOR OPTIONAL  
COOLING COIL  
FOR NON-PLATINUM  
SERIES UNITS  
Figure 7. Cut-Out Locations  
cavity. To maximize air delivery, re-  
move reducer “C” (see Figure 5) to  
obtain the largest open area that will fit  
the duct/floor construction.  
AIR DISTRIBUTION SYSTEMS  
For proper air distribution, the supply duct  
system must be designed so that the static  
pressure measured external to the furnace  
does not exceed the listed static pressure  
rating shown on the furnace rating plate.  
DUCTINSTALLATION  
Required floor, ceiling, and roof cut-out open-  
ings must be carefully located to avoid mis-  
alignment of the furnace (see Figures 6 & 7).  
Installation procedures are suggested for typi-  
cal furnace installations and need not be fol-  
lowed in the exact listed sequence.  
Three typical distribution systems are illus-  
trated in Figure 2. Location, size, and number  
of registers should be selected on the basis of  
best air distribution and floor plan of the home.  
DUCTCONNECTORSELECTION  
CUT OUT FLOOR OPENING & FUEL LINE  
HOLE  
a. Determine center of closet or alcove (Fig-  
ures 7 & 8).  
b. Locate center of the floor opening, mea-  
sured 10" from the rear wall, and mark cut-  
out measuring approximately 14-1/2" by 14-  
1/2" (± 1”) for model duct connector used  
(refer to Figures 4 & 5).  
c. Locate center of gas line hole, measured 23-  
1/4" from the rear wall and 6-5/8" to the left of  
center of the floor cut-out (See Figure 6) or  
PLATINUM SERIES  
a. For Platinum ready construction use  
the 14” round plenum, p/n: 903896.  
NON-PLATINUM SERIES  
a. Determine depth of floor cavity from  
surface of floor to top of supply air duct  
(See Figure 3).  
b. Select appropriate model from Table 5  
which matches X-dimension of the floor  
10  
 
5-1/4" to the left of center of the floor cut-out,  
or for entry through right-side of furnace  
measured 9" to the right of center of the floor  
cut-out.  
INSTALLING PLATINUM SERIES 14”  
ROUND DUCT CONNECTOR  
a. Place duct connector through the floor open-  
ing. (See Figure 9).  
d. Cut out floor opening and one gas line hole.  
b. Secure duct connector to floor.  
CUT DUCT OPENING (FINGER TABBED  
ONLY)  
INSTALLING SCREW DOWN DUCT CON-  
NECTOR  
a. Place duct connector through the floor open-  
ing with bottom tabs resting on top of the  
supply air duct.  
b. Centerductconnectorandpushbackagainst  
rear edge of floor opening.  
c. Mark cut-out location (tab area) and remove  
duct connector.  
d. Cut out duct opening 1/16" larger than area  
marked.  
a. Apply a bead of caulking, mastic, or other  
approved sealant around bottom side of 1/2”  
flange and restrictor plate, when applicable.  
b. Locate the duct connector over duct and  
carefully lower screw down duct connector  
into place.  
c. Once duct connector is located on duct,  
temporarily hold in place while fastening duct  
connector to the floor using flat head screws  
or nails. Be sure flanges of duct connector  
stay in contact with the duct.  
INSTALL FURNACE MOUNTING PLATE  
a. Place mounting plate (supplied within duct  
connector) at rear of the floor opening (See  
Figure 9).  
d. Screw plenum to duct making sure a seal is  
made between the duct and the duct con-  
MOUNTING  
PLATE  
REAR WALL  
FLOOR  
OPENING  
FUEL  
LINE  
HOLES  
SUPPLY AIR DUCT  
Figure 8. Mounting Plate  
SCREWS  
SCREWS  
BEND CONNECTOR TABS  
UNDER DUCT OPENING  
MOUNTING  
PLATE  
MOUNTING  
PLATE  
MOUNTING  
PLATE  
PLENUM  
FLOOR  
OPENING  
FLOOR  
OPENING  
FUEL  
LINE  
HOLES  
FUEL  
LINE  
HOLES  
FUEL  
LINE  
HOLES  
SUPPLY AIR DUCT  
SUPPLY AIR DUCT  
14SUPPLY  
CONNECTION  
Screw Down  
Finger Tabbed  
Duct Connectors  
Platinum Series  
Duct Connectors  
Figure 9. Duct Connector  
11  
 
nector. Additional screws may be added if  
required.  
e. Cut away along edge of flange allowing the  
center to drop into the duct. Remove section  
of duct with caution, as edges will be sharp.  
attached to the sides of the duct by using sheet  
metal screws or other suitable fasteners. (See  
Figure 11).  
If sealant, mastic, or tape is used to provide a  
better seal, it should be approved by applicable  
national or local codes.  
INSTALLING FINGER TABBED DUCT CON-  
NECTORS  
a. Place duct connector through the floor open-  
ing with bottom tabs extending through the  
duct opening. (See Figure 9)  
b. Secure duct connector to floor.  
c. Bendbottomtabsunderanduptightlyagainst  
the supply air duct (See Figure 10).  
ALTERNATE ATTACHMENT METHODS  
This procedure may also be used to install a  
furnace duct connector to narrow metal  
ductwork where insufficient clearance prevents  
bending of the duct connector tabs at the  
side(s) of the duct. (See Figure 12).  
NOTE: The duct connector is designed for use  
on ducts 12" in width. When using the connec-  
tor on 12" wide ducts, there may be insufficient  
clearance to bend the tabs on two sides of the  
duct connector. In such cases the tabs may be  
1. Score and cut the top of the metal duct as  
indicated in Step 1 or Step 2. With Step 1  
choice,alsocutoutthemetalfromtheshaded  
area “A”.  
2. Fold the duct flap “B” up, (See Step 3).  
TABS  
DUCT  
TABS  
DUCT  
1. INSERT DUCT PLENUM CONNECTOR  
INTO DUCT CUT-OUT.  
2. BEND BOTTOM TABS OVER  
AND ONTO THE UNDERNEATH  
DUCT SERVICE.  
Figure 10. Installation of Duct Connector  
Duct Connector  
Narrow Duct  
Duct  
Figure 11. Narrow Duct Installation  
STEP 2.  
STEP 1.  
Fold Back Flap "B"  
Fold Back Flap"B"  
Cut  
Lines  
Duct  
Cut- Out  
Area "A"  
Cut- Out  
Area"A"  
"B"  
"B"  
"B"  
"B"  
"A"  
"A"  
"A"  
"A"  
Top of Duct  
Fold Back Flap"B"  
Fold Back Flap "B"  
Staple Folded Duct  
Flap (typ) to side of Duct  
Connector  
Bend Duct Connector Tabs Up  
and Over- (along length of duct)  
Duct  
Duct  
Duct  
Flap "B"  
STEP 4.  
STEP 3.  
Figure 12. Alternate Installation  
12  
 
NOTE: Additional fasteners may be used at  
rear, sides or through door frame, as desired,  
to secure furnace to closet or alcove framing.  
SLIDE FURNACE  
ALL THE WAY BACK  
ONTO MTG. PLATE  
MTG. PLATE TABS  
SECURE FURNACE  
WITH 2 FASTENERS AT FRONT  
CORNER HOLES  
VENTINGANDCOMBUSTIONAIR  
REQUIREMENTS  
!
CAUTION:  
Snow must not be allowed to restrict or  
block the combustion air intake or vent  
pipes.  
Figure 13. “A”, “B”, & Platinum  
Cabinet Furnaces  
General  
NORDYNE condensing furnaces must be  
installed with outdoor combustion air piped  
directly to the furnace. Codes refer to this  
type of installation as direct vent, or two pipe  
installation.  
SLIDE FURNACE  
ALL THE WAY BACK  
ONTO MTG. PLATE  
MTG. PLATE TABS  
SECURE FURNACE  
WITH 2 FASTENERS  
AT FRONT CORNER HOLES  
FUEL  
LINE  
HOLES  
Provisions must be made for adequate supply  
of air for combustion and ventilation. For  
United States installations, the adequacy of  
air provisions can be determined by consulting  
the current version of the National Fuel Gas  
Code (ANSI Z223.1/NPFA-54). For Canadian  
installations, requirements are specified in the  
National Standard of Canada (CAN/CGA  
B149.1 & .2). Consult local codes for special  
requirements.  
Figure 14. “A” Cabinet Furnace on 911969  
Coil Cabinet (Non-Platinum Series)  
3. At the front-to-back of duct run (Area “A”),  
bend the duct tabs and secure them directly  
to the duct.  
4. At Area “B”, bend the duct tabs up and back  
over, around the duct connector, (See  
Step 3).  
NOTE: If the furnace is operated without  
adequate air for combustion and ventilation, it  
may not perform properly. Furnace  
components may be strained by high  
temperature and could fail prematurely.  
5. Fold/form the duct flap against the side of the  
duct connector and attach as shown, (See  
Step 4). Use three (3) staples (minimum) on  
each duct flap OR, if a 2X block/joist is not  
provided, use two (2) sheet metal screws  
(minimum) on each duct flap. An alternate  
attachment method is acceptable, as long  
as the plenum is securely attached.  
6. Tape the duct flap edges with an approved  
tape for a leak-free joint.  
!
WARNING:  
The combustion air piping must not be  
blocked or restricted in any manner.  
INSTALL FURNACE  
a. Remove furnace outer door(s) and bottom  
fuel line knockout.  
b. Place furnace onto duct connector and cen-  
ter with floor opening.  
c. Slide onto mounting plate. (Bottom rear slots  
on furnace should engage with mounting  
plate tabs.)  
!
WARNING:  
Furnace installation using methods  
other than those described in the  
followingsectionsmustcomplywiththe  
National Fuel Gas Code and all  
applicable local codes to provide  
sufficientcombustionairforthefurnace.  
d. Secure front with one (1) fastener at each  
corner (See Figure 13 or 14).  
13  
 
that there is no blockage or re-  
striction, leakage, corrosion and  
other deficiencies which could  
cause an unsafe condition.  
!
CAUTION:  
Do not allow debris to fall into the fur-  
nace. This could cause unsafe opera-  
tion and voids the furnace warranty.  
3. So far as is practical, close all  
building doors and windows and  
all doors between the space in  
whichtheappliance(s)connected  
to the venting system are located  
and other spaces of the building.  
4. Follow the lighting instructions.  
Place the appliance being  
inspected in operation. Adjust  
thermostat so appliance shall  
operatecontinuously.  
VENTINGREQUIREMENTS  
!
WARNING:  
FURNACE MUST NOT BE COMMON  
VENTED WITH OTHER APPLIANCES.  
5. Turn on clothes dryers and any  
other appliance not connected to  
the venting system. Turn on any  
exhaustfans,suchasrangehoods  
and bathroom exhausts, so they  
shall operate at maximum speed.  
Do not operate a summer exhaust  
fan.  
General  
Thissectionspecifiesinstallationrequirements  
for 2-pipe combustion air piping. The capacity  
table provided in this section applies to the  
maximum equivalent lengths of vent and  
combustion air intake pipe.  
These condensing furnaces are classified as  
"Category IV" appliances, which require  
special venting materials and installation  
procedures. Category IV appliances operate  
with positive vent pressure and therefore  
require vent systems which are thoroughly  
sealed. They also produce combustion  
condensate, which is slightly acidic and can  
cause severe corrosion of ordinary venting  
materials. Furnace operation can be adversely  
affected by restrictive vent and combustion  
air piping. Therefore, vent and combustion air  
piping lengths must conform completely to the  
requirements of Table 6.  
6. Close fireplace dampers.  
7. Test for spillage from draft hood  
equipped appliance at the draft  
hoodreliefopeningafter5minutes  
of main burner operation. Use the  
flame of a match or candle.  
8. If improper venting is observed  
during any of the above tests, the  
ventingsystemmustbecorrected  
in accordance with the National  
FuelGasCode,ANSIZ223.1/NFPA  
54and/orCSAB149.1,NaturalGas  
and Propane Installation Codes.  
9. After it has been determined that  
each appliance connected to the  
venting system properly vents  
when tested as outlined above,  
return doors, windows, exhaust  
fans, fireplace dampers and any  
other gas burning appliance to  
their previous conditions of use.  
The furnace must be vented to the outdoors.  
!
WARNING:  
CARBON MONOXIDE POISONING  
HAZARD  
1. Seal any unused openings in the  
venting system  
2. Inspect the venting system for  
proper size and horizontal pitch,  
as required in the National Fuel  
Gas Code, ANSI Z223.1 or the  
CAN/CGAB149InstallationCodes  
andtheseinstructions. Determine  
It must not be vented in common with any  
other appliance, even if that appliance is of the  
condensing type. Common venting can result  
in severe corrosion of other appliances or their  
venting and can allow combustion gases to  
14  
 
*NOTES  
1.  
2.  
3.  
Subtract3.5ft.foreachadditional3"90degreeelbow.  
MAXIMUM  
DIRECT VENT, DUAL  
PIPE LENGTH (ft.)*  
Two45degreeelbowsareequivalenttoone90degreeelbow.  
One short radius elbow is equivalent to two long radius  
elbows.  
Donotincludeterminationelbowsincalculationofventlength.  
Thistableisapplicableforelevationsfromsealevelto4000  
ft. Forhigherelevations,decreaseventpipelengthsby8%per  
1000ft.ofaltitude.  
APPLICATION  
Inlet/Outlet  
PVC,CPVC or ABS  
4.  
5.  
SCH. 40 Pipe Size  
Model M3RL 060  
3"  
50  
50  
3"  
50  
50  
Model M3RL 080  
6.  
Onlytheabovepipematerialsareapprovedforusewiththese  
condensingfurnaces.  
Table 6. Vent Table  
VENT TERMINAL  
AIR SUPPLY INLET  
AREA WHERE TERMINAL IS NOT PERMITTED  
Canadian Installations1  
US Installations2  
Clearance above grade, veranda, porch,  
deck, or balcony  
12 inches (30 cm)  
12 inches (30 cm)  
A =  
B =  
Clearance to window or door that may be  
opened  
6 inches (15 cm) for appliances 10,000 6 inches (15 cm) for appliances 10,000  
Btuh (3 kW), 12 inches (30 cm) for  
appliances > 10,000 Btuh (3 kW) and  
Btuh (3 kW), 9 inches (23 cm) for  
appliances > 10,000 Btuh (3 kW) and  
100,00 Btuh (30 kW), 36 inches (91 cm) for 50,000 Btuh (15 kW), 12 inches (30 cm) for  
appliances >100,00 Btuh (30 kW)  
appliances > 50,000 Btuh (15 kW)  
Clearance to permanently closed window  
Vertical clearance to ventilated soffit  
located above the terminal within a  
horizontal distance of 2 feet (61 cm) from  
the center line of the terminal  
C =  
D =  
*
*
*
*
Clearance to unventilated soffit  
Clearance to outside corner  
Clearance to inside corner  
Clearance to each side of center line  
extended above meter/regulator assembly above the meter/regulator assembly  
Clearance to service regulator vent outlet 3 feet (1.83 m)  
E =  
F =  
G =  
H =  
*
*
*
*
*
*
3 feet (91 cm) within a height 15 feet  
*
I =  
*
Clearance to nonmechanical air supply inlet 6 inches (15 cm) for appliances 10,000 6 inches (15 cm) for appliances 10,000  
J =  
to building or the combustion air inlet to any Btuh (3 kW), 12 inches (30 cm) for  
Btuh (3 kW), 9 inches (23 cm) for  
other appliance  
appliances > 10,000 Btuh (3 kW) and  
appliances > 10,000 Btuh (3 kW) and  
100,00 Btuh (30 kW), 36 inches (91 cm) for 50,000 Btuh (15 kW), 12 inches (30 cm) for  
appliances >100,00 Btuh (30 kW)  
appliances > 50,000 Btuh (15 kW)  
Clearance to a mechanical air supply inlet  
6 feet (1.83 m)  
3 feet (91 cm) above if within 10 feet (3 m)  
horizontally  
K =  
L =  
M =  
Clearance above paved sidewalk or paved 7 feet (2.13 m) †  
driveway located on public property  
*
*
Clearance under veranda, porch deck, or  
balcony  
12 inches (30 cm) ‡  
1
In accordance with the current CSA B149.1 Natural Gas and Propane Installation Code  
In accordance with the current ANSI Z223.1 / NFPA 54 National Fuel Gas Code  
A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family  
dwellings and serves both dwellings.  
2
*
Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor.  
For clearances not specified in ANSI Z223.1 / NFPA 54 or CSA B149.1, the following statement shall be included:  
“Clearance in accordance with local installation codes, and the requirements of the gas supplier and the  
manufacturer’s installation instructions.”  
Figure 15. Vent Termination Clearances for Direct Vent Furnaces  
15  
 
escape through such appliances or vents. Do  
not vent the furnace to a fireplace chimney or  
building chase.  
!
CAUTION:  
If removing an existing furnace in a venting  
system,theventingsystemmaynotbeproperly  
sized. Totesttheventsystemwiththeremaining  
appliances, follow the test outlined below.  
Combustionairmustnotbedrawnfrom  
occupied spaces and a corrosive  
atmosphere.  
The following steps shall be followed with each  
appliance connected to the venting system  
placed in operation, while any other appliances  
connected to the venting system are not in  
The quality of outdoor air must also be  
considered. Be sure that the combustion air  
intake is not located near a source of solvent  
fumes or other chemicals which can cause  
corrosion of the furnace combustion system.  
operation:  
Piping must be mechanically supported so that  
its weight does not bear down on the furnace.  
Supports must be at intervals no greater than  
five feet, and at smaller intervals if necessary  
to ensure that there are no sagging sections  
to trap water (See Figures 16 & 17).  
Vent Pipe Material  
Vent and combustion air pipe and fittings must  
be one of the following materials and must  
conformtotheindicatedANSI/ASTMstandards:  
Material  
Schedule 40 PVC  
PVC-DWV  
Standard  
D1785  
D2665  
These condensing furnaces have been  
certified for installation with zero clearance  
betweenventpipingandcombustiblesurfaces.  
However, it is good practice to allow space for  
convenience in installation and service.  
SDR-21  
& SDR-26  
ABS-DWV  
D2241  
D2661  
F628  
F891  
Schedule 40 ABS  
Foam/Cellular Core PVC  
Location of Outdoor Terminations  
Vent and combustion air intake terminations  
must be located to ensure proper furnace  
operation and to conform to applicable codes.  
Figure 15 illustrates necessary distances from  
the vent termination to windows and building  
air intakes. In Canada, the Canadian Fuel  
Gas Code takes precedence over these  
instructions. Specifically, all minimum  
distance requirements with respect to  
termination of the vent piping listed below.  
Cement and primer must conform to ATSM  
Standard D2564 for PVC and Standard D2235  
for ABS. When joining PVC piping to ABS, use  
an appropriate solvent cement and procedure  
perthepipingmanufacturer'srecommendation  
and ASTM Standard D3138.  
Vent Pipe Installation  
Pipe Routing and Support  
Route piping as directly as possible between  
the furnace and the outdoors and remember  
that routing affects pipe length limitations per  
Table 6. Locate the combustion air intake and  
the vent exhaust in the same atmospheric  
pressure zone - i.e. both must exit the building  
though the same portion of exterior wall or  
roof. Vent piping must be sloped upwards not  
less than 1/4" per foot in the direction from the  
furnace to the terminal. This is to ensure that  
any condensate flows back to the furnace  
where it can be disposed of through the  
condensate disposal system.  
The following list is a summary of vent terminal  
location requirements:  
1. The termination must be 12 inches above  
snow level or grade level whichever is  
higher. See Figure 18 for alternate method  
to achieve 12" above snow level.  
2. The minimum distance for a direct vent  
(2-pipe) installation from any door,  
openable window, or air gravity inlet is 1 ft.  
below, 1 ft. horizontally, or 1 ft. above.  
3. The vent termination shall be a minimum of  
3 ft. above any forced air inlet within 10 ft.  
4. The vent termination shall be located at  
least 4 ft. horizontally from any electric  
meter, gas meter, regulator and any relief  
equipment. These distances apply ONLY  
to U.S. installations. In Canada, the Cana-  
dian Fuel Gas Code takes precedence.  
16  
 
Downflow Furnace  
3 9/16"  
Vent  
1 7/8"  
Combustion  
Air Intake Pipe  
See Vent Table 4  
Seal/Caulk  
Around Pipe  
at Building  
Straps or Other Suitable  
Supports at Minimum of  
5 ft. Intervals  
Top View  
Coupling  
90˚ Elbow  
Offset with  
Vent for Adequate  
Dimensional Clearance  
Exhaust  
Vent  
PVC or  
ABS pipe  
Upward Pitch - 1/4" Per Foot  
Outlet Exhaust Vent  
12"  
Min.  
Wall  
First Support Should be as Close to  
Furnace Connection as Possible  
3" x 2"  
Combustion Air  
Normal Snow Level  
Furnace  
Reducer  
Intake Pipe  
Figure 16. Horizontal Venting  
Support System  
on Vertical Rise  
Below Joints  
First support should be as  
close to furnace as possible  
Combustion Air  
Intake Pipe  
5'  
Vent  
Vent  
Upward Pitch  
1/4" per foot  
Combustion Air Intake Pipe  
Figure 17. Vertical Venting  
5. Avoid areas where condensate drainage  
may cause problems by dropping on plant-  
ers or patios, etc. Also ensure that ex-  
haust gases will not impinge on windows  
or building surfaces, which may be com-  
promised or damaged by condensation.  
Do not install the vent terminal such that  
exhaust is directed into window wells,  
stairwells, under decks or into alcoves or  
similar recessed areas, and do not termi-  
nate above any public walkways.  
6. Select the point of wall penetration where  
the minimum 1/4 inch per foot of slope up  
can be maintained.  
!
CAUTION:  
For optimal performance vent furnace  
throughwallwhichexperiencestheleast  
exposure to winter winds.  
17  
 
Horizontal Venting  
2. Extend the vent pipe through the wall  
approximately 1" and seal the area be-  
tween the wall and pipe.  
3. Apply couplings to the vent pipe on the  
interior and exterior sides of the wall to  
insurethepipecannotbepushedorpulled  
through the wall.  
Vent and combustion air intake terminations  
must be as shown in Figure 19 unless the  
concentric vent termination kit is used.  
!
4. Insure the combustion air inlet pipe has a 90  
degree termination elbow, and is pointing  
downward as shown in Figures 19 & 20.  
WARNING:  
Ensurethatthecombustionairventand  
the exhaust vent are configured as  
shown in Fig. 19. Improper vent  
termination can cause recirculation of  
thefluegases.Thismayresultinfurnace  
vibration. In severe cases, the furnace  
willcycle,duetotheintermittentcontact  
betweentheflameandtheflamesensor.  
Ifyounotetheseoscillationsoccurring,  
checktheventconfiguration.Makesure  
thattheexhaustventdoesnothavea90  
degree termination.  
Note that a combustion air intake must be  
provided with an elbow opening downward.  
When the vent pipe must exit an exterior wall  
close to the grade or expected snow level, a  
riser should be provided as shown in Figure 18.  
Insulation is required to prevent freezing of this  
section of pipe.  
Vertical Venting  
For vertical venting, either the configuration  
shown in Figure 20 or the Concentric Vent  
Termination Kit may be used. Vertical venting is  
one of the shortest routing methods when  
piping vents for furnaces. The M3 furnace  
operates trouble-free when the furnace is in-  
stalled with a shorter vent.  
For horizontal venting, either the Horizontal  
Exterior Vent Mounting Kit or the Concentric  
Vent Termination Kit may be used (See Table  
12).  
• The inlet for the combustion intake pipe must  
beextendedatleastonefootabovetheroofline  
or snow accumulation level.  
• Theoutletoftheventmustbeextendedatleast  
10 inches above the inlet of the combustion air  
intake pipe.  
• The vent as well as the combustion air intake  
pipe should be located on the same side of the  
roof. Both pipes must not be closer than 5  
inches apart. They should not be separated  
more than 36 inches.  
The roof penetration must be properly flashed  
and waterproofed with a plumbing roof boot or  
equivalent flashing. Termination spacing re-  
quirements from the roof and from each other  
must be per Figure 20.  
For Canadian installations please refer to the  
Canadian Installation Code (CAN/CGA-B149.1  
or 2) and/or local codes.  
The Horizontal Exterior Vent Mounting Kit con-  
sists of two face plates and an insulating gas-  
ket to seal the exterior surface. A hole sized  
closely to the pipe diameter must first be cut  
through the wall. A short length of pipe is then  
cut such that it can penetrate the wall and be  
held in place by closely fitting standard cou-  
plings. The face plates are retained on both  
sides of the wall by the couplings, and the  
gasket is retained against the wall by the outer  
face plate. Face plates must be fastened to the  
wall and the outside one must be flashed as  
appropriate to prevent entry of water.  
Concentric Vent Termination  
A concentric vent termination is approved for  
use with these furnaces (See Table 12). For  
proper installation of the concentric vent termi-  
nation, follow the installation instructions pro-  
vided with the kit.  
When the above kits are not used the following  
steps are required:  
1. Check the hole size cut through the exte-  
rior wall. Insure that the hole diameter is  
less than the diameter of the couplings to  
be used.  
18  
 
Vent Configuration to  
Provide 12" Minimum  
height above  
Exhaust Vent  
Option B  
Mounting Kit  
Faceplate Secured  
to Wall with Screws  
Snow Level.  
Exhaust Vent  
Option A  
12" Min.  
19" Max.  
12" Min.  
36" Max.  
Combustion  
Air Inlet  
8" Min.  
Support  
Exhaust Vent  
Option C  
Outside  
Wall  
12" Above  
Normally  
Expected  
Snow  
12" min.  
36" max.  
Grade  
Level  
or Normal  
Snow  
12" Min.  
36" Max.  
12" Min. to  
7" Min.  
1/2"  
Armaflex  
Normal Snow Level  
Level  
Exhaust  
Inlet  
Insulation or  
Equivalent  
(if required)  
Figure 18. Alternate Horizontal  
Vent Installation  
Figure 19. Exhaust and Combustion Air  
Pipe Clearances  
DRAINAGEOFCONDENSATE  
FROMFURNACE  
!
CAUTION:  
Do not install additional traps in the  
condensate drain.  
!
WARNING:  
The condensate drain may exit through the left  
side panel, the right side panel, or through the  
leftorrightholeonthebottompanel.(SeeFigure  
21). Ensure that the flexible drain hose is not  
kinked.  
Thecondensateproducedbythefurnace  
mustbedrained.Donotconnectawater  
supply to the drainage hose of the  
furnace.  
NOTE: The condensate drain should be pro-  
tected from freezing when in unheated spaces.  
The condensate should drain from the plastic  
collector box (location A in Figure 21) as drop-  
lets or a small stream. If you notice the furnace  
has operated for more than 5 minutes without  
draining or the red status light on the control  
board is pulsing a 2-blink code follow the steps  
below.  
The furnace is supplied with an internal conden-  
sate drain trap.  
5" Min.  
A= 12" Above Roof or  
36" Max.  
Note: If terminations meet-  
ing these vertical require-  
Snow Accumulation Level  
Exhaust  
Vent  
Elbow  
ments exceed the maximum  
height for safe transit, the  
vent and combustion air in-  
takes may be shipped with  
the home for assembly on  
site. The furnace must be  
labeledtonotifytheinstaller/  
user not to use the furnace  
Combustion  
1"  
Air Intake  
10" Min.  
A
until the vent and combus-  
Exhaust  
tion air intake terminations  
Plumbing Vent  
are installed.  
Roof Boot  
(Typ. Both Pipes)  
Figure 20. Vertical Vent Termination  
19  
 
Collector  
Box  
A
Clamp  
Step 1: Loosen  
Step 2: Rotate to drain direction  
Step 3: Retighten  
Burner  
Box  
Keep  
Downward  
Slope  
“Hard”  
J DrainTube  
Floor  
Alt. Drain  
Alt. Drain  
Alt. Drain  
Alt. Drain  
Figure 21. Furnace with Condensate Drain Trap Assembly  
1. Remove the collector box soft tube at  
readily accessible for service and/or emer-  
gency use. Consult the local utility or gas  
supplier for additional requirements regarding  
placement of the manual main gas shut-off. In  
the absence of local codes, the gas line instal-  
lation must comply with the provisions stated in  
the Federal Manufactured Home Standard  
(H.U.D Title 24, part 280) and the National Fuel  
Gas Code (ANSI Z223.1/NFPA-54) or (CAN/  
CGA B149) installation codes.  
location A in Figure 21 and insure the exit  
from the collector box is clear of any  
debris or obstructions.  
2. Replace this tube and insure the fit to the  
headerspoutisairtight.Airwillbedrawninto  
the header if this connection is not tight.  
3. Check other tube connections along the  
drain system. Insure that all are air tight.  
NOTE: Industry research studies indicate that  
when condensate is routed to an active drain,  
household detergents, etc., buffer its acidity. If  
the drain is not actively used or if codes require,  
obtain a neutralizer kit (See Table 12). Proper  
drains and connections to the condensate tub-  
ing are required as NORDYNE cannot be held  
responsible for water leakage which occurs  
due to loose hose connections or improperly  
sealed drain line pipes.  
A drip leg should be installed in the vertical pipe  
run to the unit. Table 7 lists gas flow capacities  
for standard pipe sizes as a function of length  
in typical applications based on nominal pres-  
sure drop in the line.  
NOTE: Gas piping must not be run in or through  
air ducts, gas vents, etc.  
Compounds used on threaded joints of gas  
piping must be resistant to the actions of lique-  
fied petroleum gases.  
GAS SUPPLY AND PIPING  
General  
This furnace is equipped for bottom, left, or  
right side gas entry. Typical gas service hook-  
ups are shown in Figure 22. When making the  
gas connection provide clearance between the  
gas supply line and the entry hole in the furnace  
casing to avoid unwanted noise and/or damage  
to the furnace.  
!
CAUTION:  
Do not use matches, lighters, candles,  
orothersourcesofopenflametocheck  
for gas leaks.  
All gas piping must be installed in compliance  
with local codes and utility regulations. Some  
localregulationsrequiretheinstallationofamanual  
mainshut-offvalveandgroundjointunionexter-  
nal to the furnace. The shut-off valve should be  
NOTE: When pressure testing gas supply  
lines at pressures greater than 1/2 psig (14 in.  
water column), the furnace must be discon-  
nected from the gas supply piping system to  
prevent damage to the gas control valve.  
20  
 
CONVERSION  
This furnace can be converted from the fac-  
tory-equipped gas to either natural gas (for LP  
gas ready models), or LP gas (for natural gas  
ready models). Conversions must be made by  
qualified service personnel, using only factory  
authorized or approved parts. The required  
conversion orifices are supplied with the fur-  
nace.  
Main  
Blower  
Control  
Board  
!
WARNING:  
DO NOT REMOVE OR DEFACE THE  
Inducer  
ORIGINAL RATING PLATE.  
Burner  
Box  
Gas  
Valve  
!
CAUTION:  
Floor  
The gas supply shall be shut off prior to  
disconnecting the electrical power,  
beforeproceedingwiththeconversion.  
Alt. Gas  
Line Entry  
To Gas  
Supply  
To Turn Off Fuel Supply to the Appliance:  
Figure 22. Typical Gas Piping  
1. Set the room thermostat to “OFF” or its  
lowest temperature setting.  
2. Turn OFF the main gas supply to the appli-  
ance at the manual valve, outside of the  
appliancecasing.  
3. Remove the control access panel / lou-  
vered door.  
If the test pressure is less than or equal to 1/2  
psig (14 in. water column), the furnace must be  
isolated from the gas supply line by closing the  
manual shut-off valve.  
4. Movetheappliancegasvalvelever/knobto  
the “OFF” position.  
5. Turn OFF the electrical power to the appli-  
ance.  
Leak Check  
After the gas piping to the furnace is complete,  
all connections must be tested for gas leaks. To  
check for leaks use only a soap and water solu-  
tion or other approved method.  
CAPACITY OF BLACK IRON GAS PIPE (CU. FT. PER HOUR)  
FOR NATURAL GAS (SPECIFIC GRAVITY - 0.60)  
High Altitude Derate  
NOMINAL  
LENGTH OF PIPE RUN  
(feet)  
The nameplate input rating for the furnaces  
apply for elevations up to 4,000 feet above sea  
level for US and Canada. If the elevation for the  
furnace location is higher than 4,000 feet above  
sea level, the furnace input must be derated by  
using the appropriate orifice size listed in  
Table 8.  
BLACK IRON  
PIPE DIAMETER  
(in.)  
1/2  
10  
130  
20  
90  
30  
75  
40  
65  
50  
55  
60  
50  
70  
45  
95  
80  
40  
90  
3/4  
280 190 150 130 115 105  
1
520 350 285 245 215 195 180 170  
1050 730 590 500 440 400 370 350  
1600 1100 890 760 670 610 560 530  
1 1/4  
1 1/2  
The cubic feet per hour listed in the table above must be greater than  
the cubic feet per hour of gas flow required by the furnace.  
Todeterminethecubicfeetperhourofgasflowrequiredbythefurnace,  
divide the input rate of the furnace by the heating value of the gas:  
NOTE: The density of air decreases with in-  
creasing elevation above sea level. This re-  
duces the quantity of combustion air drawn into  
thefurnaceundernormaloperationandrequires  
the unit be derated by using smaller gas orifices  
or lower manifold pressure.  
CubicFeet  
PerHourRequired  
InputToFurnace(Btu/hr)  
HeatingValueofGas(Btu/Cu.Ft.)  
=
Table 7. Capacity of Black Iron Gas Pipe  
(cu. ft. per hour) for Natural Gas  
(specific gravity = .60)  
21  
 
To Remove the Burner Assembly:  
!
CAUTION:  
1. Follow the instructions “To Turn Off the  
Fuel Supply to the Appliance.”  
2. Disconnect the flame sensor wire from the  
burner box.  
3. Disconnect the ignitor wires at the 2 pin  
plug. This is a locking quick connect and  
both sides of the lower section must be  
depressed in order to be separated.  
4. Remove the wires from the terminals of  
the gas valve.  
Caution: Do not re-drill the burner  
orifices. If the orifice size must be  
changed, use only new orifices.  
Note: The size of the new orifices that will be  
installed into the unit will depend upon the  
typeofconversion(sealevelorhighaltitude;  
natural gas or LP gas).  
5. Disconnect the rubber pressure tubes  
from the gas valve and the burner box.  
6. Remove the burner access cover plate  
from the burner box.  
7. Remove supply gas piping from the gas  
valve.  
8. Carefully remove the burner assembly fas-  
teners and remove the burner assembly  
from the appliance. Keep the fasteners that  
were removed. Note that the burner box may  
have hooks near the top and on the right and  
left hand sides. To remove this type of burner  
box, lift the burner box upwards and then  
remove the box from the unit.  
To Convert the Unit to the Alternate Gas  
1. Remove the orifice bag from the manifold  
of the unit.  
2. Install the appropriate gas burner orifices  
into the gas manifold. Remember if in-  
stalling at altitudes above 4,000 feet to  
install the proper orifices, shown in Table  
8. When installing the new orifices, DO  
NOT use pipe joint compound on the  
orifice threads. Screw the orifices into the  
manifold by hand until snug to eliminate  
cross threading, then tighten with a  
wrench. Before installing an orifice, check  
the face or side of the orifice for the drill  
number to ensure that it is the appropriate  
size.  
3. For the conversion to the alternate fuel,  
the gas valve regulator cap must be turned  
over, as shown in Figure 23. You will  
unscrew the cap and reinstall for your in-  
stallation. Afterreinstallingthecap,youwill  
be able to read "NAT" for the conversion to  
natural gas or "LP for the conversion to LP  
gas.  
To Remove the Burner Orifices:  
1. Remove the four (4) fasteners that secure  
the gas manifold to the burner box, as  
shown in Figure 25. Carefully remove the  
gas manifold assembly from the burner  
box. Note that the gas manifold assembly  
consists of the gas valve, the gas manifold,  
and the orifices.  
2. Carefullyremovetheburnerorificesfromthe  
gas manifold, as shown in Figure 25.  
Furnace Rating  
Plate Input  
(Btuh)  
Elevation  
0 - 2000  
Elevation  
4000-6000  
Elevation  
6000-8000  
Elevation  
8000-10000  
Elevation  
2000-4000  
Furnace  
Model Number  
M3RL -  
No. of  
Burners  
Nat  
LP  
57  
Nat  
50  
LP  
Nat  
LP  
Nat  
LP  
Nat  
52  
LP  
59  
58  
060A-A/BW  
080A-A/BW  
60,000  
80,000  
4
5
50  
49  
57  
51  
50  
58  
57  
51  
50  
58  
57  
1.15 mm  
49  
1.15 mm  
51  
Table 8. Approximate Orifice Size for Natural and LP Gases  
22  
 
Reinstalling the Burner Assembly:  
OR  
Honeywell  
Valve  
1. Reinstall the gas manifold assembly to the  
burner box with the four (4) fasteners,  
which were removed earlier.  
OTHER SIDE  
OF CAP  
PRESSURE  
REGULATOR  
CAP  
2. Carefully reinstall the burner box into the  
unit. After installing the burner, inspect  
the alignment of the burners with the heat  
exchanger tubes. The center of the burn-  
ers should be aligned with the center of the  
tubes.  
M11678  
3. Reconnect the gas piping to the gas valve.  
4. Reconnectthewirestothegasvalve termi-  
nals.  
5. Reconnecttherubberpressuretubestothe  
gasvalveandtheburnerbox. Reinstallthe  
burner access cover plate.  
Figure 23. Convertible Pressure  
Regulator Cap  
6. Reconnect the ignitor at the 2 position  
plug.  
7. Reconnect the flame sensor wire to the  
burner box.  
Pressure Gauge Installation  
NOTE: For natural gas installations, the in-  
coming gas line pressure at the gas valve inlet  
must be between 4.5” WC and 10.0” WC. For  
LP gas installations, the incoming gas line pres-  
sure at the gas valve inlet must be between  
11.0” WC and 14.0” WC. This pressure can be  
checked at the inlet end of the gas valve using  
a pressure gauge or U-tube manometer, which  
must be installed according to the  
manufacturer’s supplied instructions.  
Figure 24. Burner Inspection  
Burner  
Gas  
Orifices  
Manifold  
Flame  
Observation  
Port  
On/Off  
Lever  
LIGHTINGANDADJUSTMENTOF  
THEAPPLIANCE  
1. Turn ON the gas at the manual valve,  
outside of the unit.  
Burner  
Box  
Inlet  
Pressure  
Tap  
Access  
Cover  
Plate  
Inlet  
2. Check all gas connections for leaks with  
a soap and water solution. If the solution  
bubbles there is a gas leak which must be  
corrected. Do NOT use an open flame to  
check for gas leaks.  
Gas  
Valve  
Figure 25. Typical Installation For Sealed  
Burner Box With Access Cover Plate  
3. Turn ON the electrical power to the appli-  
ance.  
5. Set the room thermostat to a point above  
room temperature to begin the heating  
cycle of the unit.  
6. Check that the unit ignites and operates  
properly. Refer to the installation instruc-  
tions provided with your unit for the normal  
operating sequence.  
4. Move the gas valve lever/knob to the “ON”  
position. The lever/knob must be moved  
to the end of its range of motion to insure  
the valve is completely open. Use only  
your hand to push in or turn the gas control  
valve. Never use tools.  
23  
 
7. After the flame ignites, visually inspect the  
burner assembly to ensure that the flame  
is drawn directly into the center of the heat  
exchanger tube, as shown in Figure 23.  
The end of the flame will be out of sight  
around the bend of the heat exchanger  
tube. Inaproperlyadjustedburnerassem-  
bly, the flame color should be blue with  
some light yellow streaks near the outer  
portions of the flame.  
!
CAUTION:  
To avoid electric shock, personal  
injury, or death, turn off the power at  
the disconnect or the main service  
panel before making any electrical  
connections.  
ELECTRICAL WIRING  
NOTE: Until all of the air is bled out of the gas  
line,thehotsurfaceignitormaynotignitethegas.  
Iftheignitioncontrollocksout,turnthethermostat  
toitslowestsettingandwaitoneminutethenturn  
thethermostattoapointaboveroomtemperature  
and the ignitor will try again to ignite the main  
burners. This process may have to be repeated  
severaltimesbeforetheburnerswillignite. Once  
the burners are lit, check all gas connections for  
leaks again with the soap and water solution. If  
the solution bubbles there is a gas leak which  
must be corrected. Do not use an open flame to  
check for gas leaks.  
General  
Electrical connections must be made in accor-  
dance with all applicable local codes and ordi-  
nances, and with the current revision of the  
National Electric Code (ANSI/NFPA 70).  
For Canadian installations electrical connec-  
tions and grounding must be done in accor-  
dance with the current Canadian Electrical  
Code (CSA C22.1 Part 1) and/or local codes. If  
any of the original wire as supplied with the  
furnace must be replaced, it must be replaced  
with wire having a minimum temperature rating  
of 105°C. Refer to the furnace nameplate and  
Table 8 for electrical requirements.  
Manifold Pressure  
The gas valve for the M3 furnace series is  
equipped with a special conversion pres-  
sure regulator cap. The pressure regulator  
cap is factory set. If the gas valve is con-  
verted from natural gas to propane gas or  
vise versa, the manifold pressure of the gas  
valve will be set to pressure listed in Table 9.  
Line Voltage Wiring  
The line voltage (115 volt) to the furnace must  
be supplied from a dedicated branch circuit  
containing the correct fuse or circuit breaker  
for the furnace. See Table 10. An electrical  
switch should be readily accessible from and  
within sight of the furnace. See the Wiring  
Diagram label in the furnace for more details.  
Type of Fuel  
Manifold Pressure  
In. WC  
Natural Gas:  
Propane (LP) Gas:  
3.5  
10.0  
The furnace cabinet must have an uninter-  
rupted, unbroken ground to minimize injury  
should an electrical fault condition occur. The  
controls used in this furnace require an earth  
ground to operate properly. Acceptable meth-  
ods for grounding are electrical wire or conduit  
approved for electrical ground service. Do not  
use gas piping as an electrical ground.  
Table 9. Manifold Pressure  
COMPLETING THE CONVERSION  
1. Affix the gas valve conversion label found  
in the package with the orifices to the unit  
rating plate.  
2. Run the appliance through a complete  
cycle to assure proper operation.  
NOTE: Proper line voltage polarity must be  
maintained in order for the control system to  
operate correctly. Verify that the incoming neu-  
24  
 
tral line is connected to the white wire and the  
incoming "hot" line is connected to the black  
wire in the furnace junction box. The furnace will  
not operate unless polarity and ground are  
properly connected. See Figure 26.  
Low Voltage Wiring  
Install the thermostat per the manufacturer's  
instructions. The low voltage (24 volt) connec-  
tions from the thermostat are made at the  
terminalstriponthecontrolboardinthefurnace.  
See Figure 28 for the proper connections for  
heating only (two-wire) and heating/cooling  
(four-wire) applications. The recommended  
minimum wire gauge for thermostat wiring is  
shown in Table 10.  
!
CAUTION:  
Label all wires prior to disconnection  
when servicing controls. Wiring errors  
can cause improper and dangerous  
operation.  
3 Amp Fuse  
Blower Off  
COM  
Timing  
24 V  
TWIN  
Verify proper operation after servicing.  
Flame Signal  
Light (Yellow)  
Status  
Light (Red)  
9
8
7
6
5
4
3
2
1
!
ATTENTION:  
Lors des opérations d'entretien des  
commandes, étiqueter tous les files  
avantdeslesdéconnecter. Touteerreur  
de câblage peut être une source de  
danger et de panne.  
Common  
Leads  
Neutrals  
Unused Motor  
Leads  
Connect  
Neutral  
Lead of  
6
3
2
1
5
4
Electronic  
Air Cleaner  
and/or Humidifier  
Here.  
Electronic Air Tap  
(.5A@ 120 VAC)  
Humidifier Tap  
(.5A@ 120 VAC)  
S'assurer du bon fonctionnement de  
l'appareil après tout entretien.  
These motor speed taps are  
not used for two-stage models  
Figure 27. Blower Speed Tap Location  
Furnace  
Input  
Cabinet  
Width  
(in.)  
Nominal  
Electrical  
Supply  
Maximum Minimum Maximum Minimum  
Maximum  
Operating Operating Furnace  
Wire  
Fuse or Circuit  
Breaker Amps*  
(Btuh)  
Voltage  
Voltage  
Amperes  
Gauge  
60,000  
80,000  
19.75  
19.75  
115-60-1  
115-60-1  
127  
127  
103  
103  
9.7  
9.7  
14  
14  
15  
15  
Recommended Thermostat Wire Length  
Thermostat Wire Gauge  
2-wire (heating)  
4 or 5-wire (cooling)  
24  
22  
20  
18  
55 ft.  
90 ft.  
140 ft.  
225 ft.  
25 ft.  
45 ft.  
70 ft.  
110 ft.  
* Time-delay fuses or HACR-type circuit breakers are required.  
Table 10. Electrical Data  
Field Supplied  
Field Supplied  
Fused Service  
Panel Connector  
Panel  
Field Line Voltage  
Wiring  
Black (Hot)  
Black  
White  
Black  
White  
Black  
White  
Factory Line  
Voltage Wiring  
White (Neutral)  
Green or Bare  
(Ground)  
Ground  
Ground  
Ground  
Junction Box (may be internal  
or external to the furnace). These  
connections can be made in the  
field supplied disconnect at the  
furnace.  
Field Supplied Disconnect  
Within Sight of Furnace  
Figure 26. Line Voltage Field Wiring  
25  
 
A/C Condensing Unit  
The thermostat must not be installed on an  
outside wall or any other location where its  
operation may be adversely affected. Adverse  
affects include radiant loading from fireplaces,  
sunlight, or lighting fixtures, and convective  
loading from warm air registers or electrical  
appliances.  
Condensing Unit  
Control Box  
Blower Off  
Timing  
COM  
24 V  
3 Amp  
Fuse  
Connect  
R & W  
For  
Heating  
Only  
TWIN  
Flame Signal Light  
(Yellow)  
To check the heat anticipator setting either:  
Status Light  
(Red)  
Room  
Thermostat  
9
8
7
6
5
4
3
2
1
1. Add the current draw of the system com-  
ponents; or  
NOTE:The "Y"  
terminal on the  
UTEC control board  
must be connected  
to the thermostat  
for proper cooling  
mode operation.  
2. Measurethecurrentflowonthethermostat  
R-Wcircuitafterthecirculatingblowermotor  
has started.  
Neutrals  
Unused Motor Leads  
FIELD WIRING  
Low Voltage  
Connections  
6
5
4
3
2
1
Set the heat anticipator according to the ther-  
mostat manufacturer's instructions for heat  
anticipator settings.  
Figure 28. Low Voltage Field,  
Four-wire Heating/Cooling Applications  
VENTILATION  
Ventilation must be provided for homes built to  
HUD Manufactured Homes Safety and Con-  
structionStandards.Thisventilationcanbesup-  
plied by the VentilAire III or VentilAire IV acces-  
sories. (See Table 12). Alternate means to pro-  
vide the ventilation air must meet the require-  
ments of all applicable local and federal codes.  
4. The roll-out and vent safety manual reset  
switches are closed. If necessary, press  
the red button to reset a switch. See  
Figure 26 for location. DO NOT install a  
jumper wire across a switch to defeat its  
function. If a switch reopens on start-up,  
DO NOT reset the switch without identify-  
ingandcorrectingthefaultconditionwhich  
caused the switch to trip.  
For installation of the VentilAire III or IV, follow  
the instructions provided with the VentilAire  
kit.  
5. The blower door is in place, closing the  
door switch in the line voltage circuit.  
START-UPANDADJUSTMENTS  
General  
Prior to start-up, verify that:  
6. The gas line has been purged and all  
connections are leak tight.  
1. The line voltage power leads are securely  
connected, that the polarity of the con-  
nections is correct, and that the furnace  
is properly grounded.  
Start-Up Procedure  
1. Set the thermostat to the lowest setting.  
2. Close the disconnect(s) to provide line  
voltage to the furnace.  
2. The thermostat wires (R, W, Y, and G) are  
securely connected to the correct leads  
on the terminal strip of the circuit board.  
3. Follow the procedures given on the oper-  
ating instructions label attached to the  
furnace.  
3. The natural gas line service pressure must  
not exceed 10.0 in. water column (0.36  
psig), and must not be less than 4.5 in.  
water column (0.16 psig). For LP gas the  
line service pressure must not exceed 14  
in. water column (0.51 psig), and must not  
be less than 11.0 in. W.C. (0.40 psig).  
4. Set the thermostat above room tempera-  
ture and verify the sequence of operation.  
(See the SEQUENCE OF OPERATION.)  
26  
 
5. After the furnace has run for approximately  
five minutes, set the thermostat below room  
temperature and verify steps 9 - 11 of the  
SEQUENCE OF OPERATION.  
6. See the "High Altitude Derate" section for  
additionalinformationonfiringrateateleva-  
tions above 4,000 ft.  
The gas valve regulator is set at a nominal  
value of 3.5 in. water column for use with natural  
gas.Themanifoldpressuremustbesetat10.0in.  
water column for use with LP gas.  
Shut Down Procedure  
In the event that the furnace must be shut down,  
follow this procedure:  
1. Set the room thermostat to "OFF" or its  
lowest temperature setting.  
Verifying and Adjusting Temperature Rise  
Verify that the temperature rise through the  
furnace is within the range specified on the fur-  
naceratingplate. Temperaturerisesoutsidethe  
specified range could result in premature heat  
exchangerfailure.  
2. Turn OFF the main gas supply to the appli-  
ance at the manual valve outside of the  
appliancecasing.  
3. Remove the control access panel / lou-  
vered door.  
Place thermometers in the return and supply  
air stream as close to the furnace as possible.  
The thermometer on the supply air side must  
be shielded from direct radiation from the heat  
exchanger to avoid false readings. Adjust all  
registers and duct dampers to the desired  
position and run the furnace for fifteen minutes  
before taking any temperature readings. The  
temperature rise is the difference between the  
supply and return air temperatures.  
4. Move the appliance gas valve lever/knob  
to the “OFF” position.  
5. Turn OFF the electrical power to the  
appliance.  
Verifying Firing Rate  
The firing rate must be verified for each instal-  
lation to prevent over-firing the furnace.  
NOTE: The firing rate must not exceed the  
rate shown on the furnace rating plate. At  
altitudes above 4000 ft. it must not exceed  
that on the rating plate less 4% for each  
1000 ft.  
For typical duct systems, the temperature rise  
will fall within the range specified on the rating  
plate with the blower speed at the factory  
recommended setting. If the temperature rise  
measured is outside the range specified, it may  
be necessary to change the blower speed.  
Lower blower speeds will increase the tem-  
perature rise and higher blower speeds will  
decrease the temperature rise.  
Use the following procedure to determine the  
firing rate:  
1. Shut off all other gas fired appliances.  
2. Start the furnace and allow it to run for at  
least three minutes.  
The furnace is equipped with a multispeed  
motor. Heating and cooling speed selection is  
made by moving the leads on the integrated  
control board located in the furnace. The wiring  
diagram on the furnace and Figure 30 show the  
speed taps for adjusting motor speed.  
3. Measure the time (in seconds) required for  
the gas meter to complete one revolution.  
4. Convert the time per revolution to cubic  
feet of gas per hour using Table 11.  
Ifitisdesiredthatthebloweroperateatthesame  
speed for heating and cooling, tape off the  
terminal of the unused blower wire. Install the  
jumper wire, found in the plastic instruction bag,  
across the HEAT and COOL taps on the control  
board. Reconnect the desired blower tap to the  
piggyback quick connect.  
5. Multiply the gas flow rate in cubic feet per  
hour by the heating value of the gas in Btu  
per cubic foot to obtain the firing rate in  
Btuh. Example:  
Time for 1 revolution of a gas meter  
with a 1 cubic foot dial = 60 seconds.  
From Table 11 read 60 cubic feet per  
hour of gas.  
Heating value of the gas (obtained  
from gas supplier) = 1000 Btu per  
cubic foot.  
The blower control is designed to start the  
circulating air blower 30 seconds after the gas  
valve is opened. The blower control is factory  
wired to turn the blower motor off 120 seconds  
Firing rate = 1000 x 60 = 60,000 Btuh.  
27  
 
GAS FLOW RATE (CUBIC FEET PER HOUR)  
CUBIC FEET PER REVOLUTION OF  
TIME FOR  
ONE REVOLUTION  
TIME FOR  
ONE REVOLUTION  
CUBIC FEET PER REVOLUTION OF  
METER  
METER  
5
(SECONDS)  
1
10  
(SECONDS)  
80  
1
5
10  
24  
26  
28  
30  
32  
34  
36  
38  
40  
42  
44  
46  
48  
50  
52  
54  
56  
58  
60  
62  
64  
150  
138  
129  
120  
113  
106  
100  
95  
90  
86  
82  
78  
75  
72  
69  
67  
64  
62  
60  
58  
750  
692  
643  
600  
563  
529  
500  
474  
450  
429  
409  
391  
375  
360  
346  
333  
321  
310  
300  
290  
281  
1500  
1385  
1286  
1200  
1125  
1059  
1000  
947  
900  
857  
818  
783  
750  
720  
692  
667  
643  
621  
600  
581  
45  
44  
43  
42  
41  
40  
39  
38  
38  
37  
36  
35  
35  
34  
33  
33  
32  
32  
31  
31  
30  
225  
220  
214  
209  
205  
200  
196  
191  
188  
184  
180  
176  
173  
170  
167  
164  
161  
158  
155  
153  
150  
450  
439  
429  
419  
409  
400  
391  
383  
375  
367  
360  
353  
346  
340  
333  
327  
321  
316  
310  
305  
300  
82  
84  
86  
88  
90  
92  
94  
96  
98  
100  
102  
104  
106  
108  
110  
112  
114  
116  
118  
120  
56  
563  
Table 11. Gas Flow Rate  
temperature and verify that the Sequence of  
Operation is as described in these instructions.  
The supply air limit switch should function to  
turn off the gas valve within approximately five  
minutes. The circulating air and combustion  
blowers should continue to run when the supply  
air limit switch opens. Remove the close-off  
plateimmediatelyafterthesupplyair limitswitch  
opens. If the furnace operates for more than five  
minutes with no return air, set the thermostat  
below room temperature, shut off the power to  
the furnace, and replace the supply air limit  
switch.  
after the gas valve is closed. This timing can be  
changed using the BLOWER OFF timing switch  
opposite the terminal block on the control board  
(See Figure 27).  
VerifyingBurnerOperation  
To verify operation of the burners, remove front  
doorandensurethatthe doorswitchisintheon”  
position(seeFigure29).Setthethermostatabove  
room temperature and observe the ignition se-  
quence.Theflamecanbeobserved throughthe  
smallclearwindowontheburnerbox.Theburner  
flameshouldcarryoverbetweenallburners.The  
flamesshouldbeblue,withoutyellowtips.Flames  
should extend from each burner without lifting,  
curling,orfloating.Afterverifyingignition,setthe  
thermostat below room temperature and verify  
that the burner flame extinguishes completely.  
Replace the front door.  
DESCRIPTIONOFCOMPONENTS  
Figure 29 shows the location of each of the  
functional components described below. If any  
component of the furnace must be replaced,  
use only factory authorized replacement parts.  
Contact your distributor for the approved re-  
placement parts.  
Verifying Operation of the Supply Air  
Limit Switch  
To verify operation of the supply air limit switch,  
make sure that the blower door is in place and  
that there is power to the furnace. Completely  
block the return airflow to the furnace by install-  
ing a close-off plate in place of or upstream of  
the filter(s). Set the thermostat above room  
Flame Sensor – The flame sensor acts to  
prove that flame has carried over from the  
ignitor to the opposite end burner. If no flame is  
sensed, the furnace will be shut down automati-  
cally.  
28  
 
MAINTENANCE  
FURNACE ACCESSORY KITS  
Kit  
Order Number  
911969A  
904003  
It is recommended that the furnace be checked  
yearly. At a minimum, this check should include  
thefollowingitems:  
A/C Coil Box  
Side Return Air Kit  
Top Return Air Kit  
904015  
Sloped Roof VentilAire III Kit  
Sloped Roof VentilAire IV Kit  
Soffit VentilAire Kit  
Concentric Vent Termination Kit  
(for horizontal and vertical venting)  
Horizontal Exterior Vent  
914098  
914229  
917201  
!
WARNING:  
903578  
Toavoidelectricshock,personalinjury,  
or death, turn off the power at the  
disconnect or the main service panel  
before performing any maintenance.  
Mounting Kit  
3"PVC  
902375  
902377  
Neutralizer Kit - All Models  
Table 12. Accessory Kits  
Gas Valve – The gas valve controls the flow of  
gas to the burners. When the gas valve is  
energized it automatically opens and regulates  
the gas pressure in the manifold.  
!
WARNING:  
Holesintheventpipeorheatexchanger  
can cause products of combustion to  
enter the occupied space. Replace the  
ventpipeorheatexchangerifleaksare  
found. Failure to prevent products of  
combustion from being circulated into  
the occupied space can crate poten-  
tially hazardous conditions, including  
carbonmonoxidepoisoning,thatcould  
result in personal injury or death.  
Pressure Switch – The pressure switch veri-  
fies that the inducer is drawing the combustion  
gasesthroughtheheatexchanger. Italsosenses  
a blocked condensate drain condition.  
Deck Limit Switch (Auxiliary Limit) – The  
deck limit protects the furnace filter tempera-  
ture from overheating when the motor has  
malfunctioned. If the deck switch opens, the  
power for the furnace will shut down (see  
Figure 29).  
Combustion Air and Vent System  
Check the combustion air and vent pipe to  
ensure that it is not damaged, corroded or  
blocked by debris. Any damaged section of  
vent pipe must be replaced, and any obstruc-  
tion or blockage must be removed prior to  
operating the furnace.  
Supply Air Limit Switch – The supply air limit  
switch prevents the air temperature leaving the  
furnace from exceeding the maximum outlet air  
temperature.  
Vent Safety Switch – The vent safety switch  
shuts the furnace down if the outlet flue gas  
temperature increases above 145°F. This  
switch protects the plastic flue system and the  
inducer from over-temperature conditions.  
Air Filter  
An air filter is supplied with the furnace as  
shipped from the factory. Filters should be  
changed or cleaned monthly during the heating  
season. New or newly renovated homes may  
require more frequent changing until the con-  
struction dust has been removed.  
Flame Roll-Out Switch – This switch pro-  
vides flame roll-out protection to the furnace  
and combustion air inlet pipe.  
29  
 
• Do not store gasoline or any other  
flammable vapors and liquids in the vicinity  
of the furnace.  
!
WARNING:  
Never operate the furnace without a  
filterinplace. Dustandlintinthereturn  
air can build up on internal compo-  
nents, resulting in loss of efficiency,  
equipmentdamage, andpossiblefire.  
• Change or replace the air filters monthly  
during any period when the circulating  
blower is operating regularly.  
• Always replace the doors on the furnace  
after servicing. Do not operate the furnace  
without all doors and covers in place.  
Lubrication  
The bearings in the circulating air blower mo-  
tors are pre-lubricated and sealed at the fac-  
tory. No further oiling of the bearings is required  
for the life of the motor.  
• Avoidoperatingthefurnacewhenwindows  
and doors are open.  
• Be sure that the thermostat is properly  
installed and is not being affected by  
drafts or heat from lamps or other  
appliances.  
Condensate Drain Assembly  
Be sure the condensate lines are free and open  
(i.e. avoid kinking hoses). Also make sure all  
hose clamps are tight to avoid drawing air into  
the system.  
Sequence of Operation  
Operating sequences for the heating, cooling,  
and fan modes are described below. Refer to  
the wiring diagrams (Figures 30) and the low  
voltage field wiring diagram (Figure 26) for  
more details.  
Blower Compartment  
The blower compartment should be cleaned  
monthly during the heating and cooling sea-  
sons to remove any dirt and lint that may have  
accumulated in the compartment or on the  
blower and motor. Dirt and lint can create  
excessive loads on the motor resulting in higher  
than normal operating temperatures and short-  
ened service life.  
Heating Mode:  
1. On a call for heat the thermostat closes,  
applying 24 VAC to the W terminal on the  
control board.  
2. The control board checks for continuity  
on the 24 VAC limit control circuit (over-  
temperature limit switch, flame rollout  
switches and blocked vent switch in se-  
ries). If an open limit is detected the con-  
trol board will energize the inducer and  
the conditioned air blower. All other sys-  
tem functions will be inoperable until the  
limit circuit closes. While the limit is open,  
the red LED will pulse at a rate of 1 blink  
per unit time.  
3. The furnace control checks for continuity  
across the pressure switch (24 VAC). If  
the pressure switch is closed the heat  
mode sequence will not continue. If it  
remains closed for 10 seconds the red  
LED will blink 3 times repetitively until the  
fault condition clears.  
Heat Exchanger and Burner Maintenance  
The furnace should operate for many years  
without excessive soot buildup in the flue pas-  
sageways, however, the flue passageways,  
the vent system, and the burners should be  
inspected and cleaned (if required) by a quali-  
fied service technician annually to ensure con-  
tinued safe operation. Particular attention must  
be given to identify deterioration from corrosion  
or other sources.  
SYSTEMOPERATION  
INFORMATION  
GENERAL  
Proper maintenance is most important to  
achieve the best performance from a  
furnace. Follow these instructions for years  
of safe, trouble free operation.  
4. The inducer is energized.  
5. The pressure switch will close. If the  
pressure switch does not close after 10  
seconds the fault LED will blink 2 times  
repetitively and the inducer will continue  
to run until the switch is closed.  
6. The inducer will pre-purge for 30 seconds  
and then the igniter will start its warm-up  
as follows:  
• Do not place combustible materials on or  
against the furnace cabinet or the vent pipe.  
30  
 
InitialPowerup:After30secondsofigniter  
warm-up the gas valve (24 VAC) will then  
open. The igniter circuit will stay ener-  
gized for 3 seconds after the gas valve  
opens.  
Cooling Mode:  
1. On a call for cooling the thermostat closes,  
applying 24 VAC to the G and Y terminals  
on the furnace control. This closes the  
compressorcontactor.  
After Initial Power up: The control has a  
programmed adaptive ignition feature  
which varies the warm-up period as fol-  
lows:Ifignitionissuccessfulthewarm-upis  
reducedby3-secondsoneachsubsequent  
call for heat until ignition failure occurs.  
Upon ignition failure, the warm-up is in-  
creased by 3-seconds on the next try. If  
successful, the timing remains fixed at this  
level. In general, whenever ignition failure  
occursthewarm-upintervalisincreasedby  
3-seconds on the next try. And if success-  
ful, it remains there. Minimum and maxi-  
mum warm-up time limits are set at 6 and  
54-seconds, respectively.  
2. The furnace control energizes the circu-  
lating blower (115 VAC) on the cooling  
speed.  
3. When the thermostat is satisfied, the G  
and Y terminals on the control board are  
de-energized opening the compressor  
contactor.  
4. The circulating air blower is de-energized  
after a 90-second delay.  
Fan Mode:  
1. On a call for fan operation, the thermostat  
applies 24 VAC to the G terminal on the  
furnace control board.  
2. The circulating air blower is energized  
immediately on the heating speed.  
3. If the furnace is operated in the continu-  
ous ON position at the thermostat and is  
then switched to AUTO, the circulating  
blower will operate for a specified delay  
(factory set at 120 seconds).  
7. The furnace control must prove flame via  
the flame sensor 5 seconds after the gas  
valve opens. If flame is sensed, all burn-  
ers are on and the ignitor cools off. If no  
flame is sensed, the gas valve closes  
immediately and the inducer continues to  
run. A second trial for ignition (step 6)  
begins if no flame is sensed. On the fifth  
tryforignition, thefurnacecontrolislocked  
out and the red LED will blink 4 times  
repetitively. The thermostat must be  
opened for at least ten seconds to reset  
the furnace control after a lock out. Oth-  
erwise, the furnace will attempt another  
ignition sequence in 1 hour.  
Furnace Fails to Operate  
If the furnace does not operate check the  
following:  
1. Is the thermostat operating properly?  
2. Is the front door in place?  
3. Is the furnace disconnect closed?  
4. Has the circuit breaker tripped or the  
control board fuse burned open?  
5. Is the gas turned on?  
6. Are any manual reset switches open?  
7. Is the filter dirty or plugged?  
8. Is the flame sensor coated? (Remove  
and clean with emery cloth.)  
8. The furnace control energizes the cir-  
culating air blower on the heating speed  
30 seconds after the gas valve circuit is  
energized .  
9. When the thermostat has been satisfied,  
gas valve is de-energized.  
9. Is the deck switch open?  
10. The inducer is de-energized after a 30-  
second postpurge.  
11. The furnace control keeps the circulating  
air blower energized for 120 seconds  
(factory set) or 60, 90, or 180 seconds  
(field adjustable). (See Figure 27.)  
12. Abnormal conditions: If a limit opens during  
operation, the inducer and circulating air  
blower continue to operate. The gas valve  
is de-energized immediately. The blowers  
continue to operate until the limit closes.  
When the limit closes the inducer blower is  
de-energized immediately. The circulating  
airblowercontinuestooperateforthespeci-  
fied delay (factory set at 120 seconds).  
If the furnace locks out after 5 attempts for  
ignition, it will try again every hour if a call for  
heat remains. If the inducer and circulating air  
blowers are operating, and items 1 through 8  
have been checked, press the red reset but-  
ton on the vent safety switch. (See Figure 29.)  
If the furnace operates after depressing the  
reset button, contact a qualified service tech-  
nician to identify and repair the problem.  
If furnace still fails to operate, depress the red  
reset buttons on the flame roll-out switch. If  
the furnace operates after depressing the  
reset button, contact a qualified service tech-  
nician to identify and repair the problem.  
31  
 
M3 Downflow Furnace  
3
21  
2
8
18  
4
9
5
10  
19  
6
11  
16  
22  
7
12  
13  
17  
14  
1
15  
1 Door Assembly - Louvered  
2 Filter Inside Door  
12 Ignitor Assembly  
13 Burner View Port  
14 Main Limit Switch  
3 Blower Assembly  
4 ControlBoard  
15 Coil Cabinet Assembly (Optional)  
16 Flame Sensor (On Burner Box)  
17 Gas Valve  
5 Pressure Switch  
6 Flame Rollout Switch  
7 “J” Trap Hard Tube  
8 LowVoltageTransformer  
9 In Line Drain Assembly  
10 Junction Box  
18 Switch, On/Off  
19 Blower, Inducer  
20 Orifice(InBurnerBox)  
21 Aux. Limit  
11 Vent Safety Switch  
22 BurnerBox  
Figure 29. Location of Major Components  
32  
 
BLUE  
BLUE  
FLAME ROLL-OUT  
SWITCH  
(ALL MODELS)  
VENT  
SAFETY  
SWITCH  
SUPPLY AIR  
LIMIT SWITCH  
(ALL MODELS)  
PRESSURE  
SWITCH  
(ALL MODELS)  
WHITE  
BLACK  
WHITE (NEUTRAL)  
BLACK 120V  
GROUND  
ON/OFF SWITCH  
GREEN  
ROOM THERMOSTAT  
BLOWER DECK SWITCH  
TRANSFORMER  
WHITE W/ BLK STRIPES  
R
Y
WHITE  
120 V  
BLACK  
24 V  
G
BLK W/ WHITE STRIPES  
W
AIR CONDITIONER  
CONDENSING UNIT  
C
Y
FLAME SENSOR  
3 OR 4 SPEED MOTOR  
RED  
YELLOW  
BROWN  
C
H
MH  
ML  
GAS  
VALVE  
L
IGNITOR  
BLACK  
BLACK  
Legend  
Field Wiring  
Factory Wiring:  
RED  
1
BLACK  
R
C
ORANGE  
BLUE  
2
3
4
INDUCER  
BLACK  
BLACK  
Low Voltage  
5
High Voltage  
WHITE  
6
MOTOR  
PLUG  
STATUS  
RED  
LIGHT  
If any of the original  
FAULT CONDITION  
with  
Factory Wired  
Heating Speeds  
the furnace must be  
replaced, it must be  
replaced  
material having a  
rating of  
˚ C.  
wiring  
Furnace  
Input, Btuh  
Wire  
Color  
60,000  
80,000  
Red  
at least  
Power Off or Deck Limit Open  
OFF  
Blue  
Use copper  
conductors  
only.  
FLAME  
YELLOW  
LIGHT  
FAULT CONDITION  
WD#710240B  
Figure 30. Downflow Furnace Wiring Diagram  
33  
 
34  
 
INSTALLATION/PERFORMANCE CHECK LIST  
LOCATION ____________________ CITY __________________ STATE ____________  
INSTALLER ___________________ CITY __________________ STATE ____________  
UNIT MODEL NUMBER________________  
UNIT SERIAL NUMBER________________  
Minimum Clearances per Table 3? ________  
Electrical Connections tight? _____________  
Line Voltage Polarity correct? ____________  
Supply Voltage: ___________________ Volts  
Blower Motor HP: _____________________  
Are Flue Connections tight? _____________  
Is there Proper Draft?__________________  
Is Vent free from restrictions? ____________  
Is the Filter(s) secured in place? __________  
Is the Filter(s) clean? __________________  
FUEL TYPE:  
Natural Gas ______ LP/Propane _______  
Has the Thermostat been calibrated? _____  
Is the Thermostat level? ________________  
Is the Heat Anticipator Setting correct? ____  
Gas Piping Connections leak-tested? _____  
Gas Line Pressure: ____________________  
(in. water column, with furnace operating)  
Manifold Pressure: ____________________  
(in. water column, with furnace operating)  
Is there adequate fresh air supply for  
Has the Owner's Information been reviewed  
with the home-owner? _________________  
combustion and ventilation? _____________  
Has the Literature Package been left near the  
furnace? ____________________________  
Furnace Input: _________________ (Btuh)  
Supply Air Temperature:__________ (° F)  
Return Air Temperature: _________ (° F)  
Temperature Rise: ______________ (° F)  
35  
 
¢7082197¤  
708219E  
708219E(Replaces708219D)  
Specificationsandillustrationssubjecttochangewithout  
noticeandwithoutincurringobligations. Printedin  
U.S.A.(08/06)  
O’Fallon, MO  
 

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