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Installation InstructionsM3RL Series 90+ Downflow Condensing Furnace
Direct Vent (Sealed Combustion) Forced Air Gas Furnaces
LEAVE THESE INSTRUCTIONS WITH THE HOMEOWNER.
! WARNING:FIRE OR EXPLOSION HAZARDFailure to follow safety warnings exactly couldresult in serious injury, death or propertydamage.
! ADVERTISSEMENT:RISQUE D’INCENDIE OU D’EXPLOSIONLe non-respect des avertissements de sécuritépourrait entraîner des blessures graves, lamort ou des dommages matériels.
– Do not store or use gasoline or other flammablevapors and liquids in the vicinity of this or any otherappliance.
– WHAT TO DO IF YOU SMELL GAS• Do not try to light any appliance.• Do not touch any electrical switch; do not use any
phone in your building.• Leave the building immediately.• Immediately call your gas supplier from a neighbor's
phone. Follow the gas supplier's instructions.• If you cannot reach your gas supplier, call the fire
department.– Installation and service must be performed by a
qualified installer, service agency, or the gas sup-plier.
– Ne pas entreposer ni utiliser de l’essence nid’autres vapeurs ou liquides inflammables dans levoisinage 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.• Évacuer l’immeuble immédiatement.• Appeler immédiatement le fournisseur de gaz en
employant le téléphone d’un voisin. Respecter àla lettre les instructions du fournisseur de gaz.
• Si personne ne répond, appeler le service desincendies.
– L’installation et l’entretien doivent être effectuéspar un installateur qualifié, un organisme deservice ou le fournisseur de gaz.
For installation in:1. Manufactured Homes2. Park Models and Manufactured Buildings3. Modular Homes/Buildings
! WARNING:Should overheating occur, or thegas supply fail to shut off, shutoff the manual gas valve to theappliance before shutting off theelectrical supply.
Improper installation, adjust-ment, alteration, service ormaintenance can cause injuryor property damage. Refer tothis manual. For assistance oradditional information consulta qualified installer, serviceagency or the gas supplier.
BW Models
BWT Models
2
3
ApplicationM-Manufactured Home
Furnace Series
Comfort ModelRL - Condensing Downflow
M 3 R L - 060 A - A W
Door ColorW - WhiteG - Gray
Cabinet DimensionsA - 56" x 19-3/4" x 23-3/4”B - w/Coil Cavity, 76" x 19-3/4" x 23-3/4"
Electrical CodeA - 1PH, 60 Hz, 120 VAC
Conversion .............................................. 21
Lighting and Adjustmentof the Appliance .............................. 23
Electrical Wiring ...................................... 24Line Voltage Wiring ........................... 24Low Voltage Wiring ........................... 26
Ventilation ................................................ 26
Start-up and Adjustment ........................ 26Start-Up Procedure ........................... 26Shut Down Procedure ....................... 27Verifying and Adjusting Firing Rate ... 27Temperature Rise ............................. 27Verifying and AdjustingVerifying Burner Operation .............. 28Verifying Operation of the Supply Air Limit Switch ................. 28
Description of Components ................ 29
Furnace Accessories ............................. 29
Maintenance ........................................... 29Combustion Air and Vent System .... 29Air Filter(s) ....................................... 29Lubrication ........................................ 30Condensate Drain Assembly ........... 30Blower Compartment ....................... 30Heat Exchanger and Burner Maintenance .................................. 30
System Operation Information ............. 30Sequence of Operation .................... 30Furnace Fails to Operate ................. 31
Location of Major Components .......... 32
Wiring Diagram ....................................... 33
Installation/PerformanceChecklist ......................................... 35
General ...................................................... 4Unit Dimensions .................................. 4Shipping Weights ................................ 4Furnace Specification ........................ 4Air Flow Data ..................................... 4
Owner's Information ................................ 5
Installation Requirements ...................... 6Location .............................................. 7Clearance ........................................... 7
Circulating Air Supply ............................ 7
Return Air Provisions .............................. 8
Air Distribution Systems ........................ 9
Duct Connector Selection .................... 10
Duct Installation .................................... 10
Venting and CombustionAir Requirements ........................... 13
Venting Requirements .......................... 14Vent Table ........................................ 15Vent Pipe Material ............................ 16Vent Pipe Length and Diameter ....... 16Vent Pipe Installation ........................ 16Pipe Routing & Support .................... 16Location of Outdoor Termination ..... 16Horizontal Venting ............................ 18Vertical Venting ................................ 18Vent Freezing Protection ................. 19Concentric Vent Termination ........... 19
Drainage of Condensate From Furnace ................................ 19
Gas Supply and Piping ......................... 20Leak Check ....................................... 21High Altitude Derate ......................... 21Pressure Switch .............................. 21
TABLE OF CONTENTS
Table 1. Model Identification
Return Air ConfigurationBlank - FrontT - Top
Heating CapacityInput, BTUH (000’)
4
19-7/819-7/824-5/824-5/8
56-1/1656-1/16
20-9/3220-9/32
21-17/3221-17/32
21-29/3221-29/32
21-15/1621-15/16
19-3/1619-3/16
23-7/1623-7/16
28-15/3228-15/32
3-17/323-17/32
4-11/164-11/16 4-11/164-11/16
3-17/323-17/32
EXHAUST EXHAUST VENTVENT17-13/1617-13/16
COMBUSTION COMBUSTION AIR AIR INTAKEINTAKE21-11/3221-11/32
7/8 Diameter7/8 Diameter
1-19/321-19/32 1-19/321-19/32
EXHAUST EXHAUST VENTVENT
1-11/161-11/16
COMBUSTION COMBUSTION AIR AIR INTAKEINTAKE3-17/323-17/32
24-3/424-3/420-1/1620-1/16
18-1/218-1/2
18-1/218-1/2
(W/ Coil Box)(W/ Coil Box)
75-1/475-1/4
SIDE RETURNSIDE RETURNKNOCKOUTSKNOCKOUTS
SIDE RETURNSIDE RETURNKNOCKOUTSKNOCKOUTS
1-1/21-1/2
21-15/1621-15/16
1-19/321-19/32
CoolingCoolingCoilCoilBoxBox
(W/O Coil Box)(W/O Coil Box)
Table 2. Shipping Weight
Table 3. Furnace Specifications/Airflow Data
GENERAL
Note: Data is for Operation with Filter.* Factory Wired Cooling Tap** Factory Wired Heating Tap
Furnace Specifications / Airflow DataFurnace Furnace Temp. Recommended
Input Output Rise @ A/CBtuh Btuh .3"WC °F CFM CFM CFM CFM CFM Ton
High* 1660 1599 1544 1474 1410 4Med-High 1512 1467 1416 1363 1304 3Med-Low 1340 1304 1261 1217 1158 2.-1/2
60,000 54,000 35 - 65 Low** 1176 1142 1108 1025 966 2High* 1660 1599 1544 1474 1410 4Med-High 1512 1467 1416 1363 1304 3Med-Low** 1340 1304 1261 1217 1158 2.-1/2
80,000 72,000 35 - 65 Low 1176 1142 1108 1025 966 2
0.4 0.5Furnace Model No.
Motor HP
Motor Speed
External Static Pressure ( Inches Water Column)0.1 0.2 0.3
M3 RL-060
M3 RL-080
1/2
1/2
Top Return KnockoutsFigure 1. Furnace Dimensions
Top Return Opening(BWT Models)
* May include suffix - T
Furnace Model
Shipping Weight
(lbs ) M3RL 060A AW 150 M3RL 060A BW* 170 M3RL 080A AW 155 M3RL 080A BW* 175
Top View(AW and BW Models)
1.000
1.00
0
21.000
12.000
5
! WARNING:Do not use this appliance if any parthas been submerged under water. Im-mediately call a qualified service tech-nician to inspect the appliance and toreplace any part of the control systemand any gas control that has beensubmerged underwater.
NOTICE TO INSTALLERInstaller is advised to follow carefully all instruc-tions and warnings in this manual to insuremaximum performance, safety, and operatingefficiency of these appliances. Improper installa-tion may create hazardous conditions, and willvoid the appliance warranty.
GENERALGeneral DescriptionThe M3 series gas furnaces are listed directvent (sealed combustion) forced air furnacesfor use with both natural and propane gases.The M3 series is a Category IV and type FSPfurnace. The M3 furnace series has beencertified to the ANSI Z21.47/CSA2.3-2001 foruse in the United States and Canada and to theUL307B —1995 for use in the United States.
These furnaces may be installed in:1. Manufactured Homes.2. Park Models and Manufactured buildings3. Modular Homes/Buildings
The following are safety guidelines with refer-ences to their specific sections or pages in themanual.
1. Use only type of gas approved for thisfurnace. Refer to the furnace rating plate.
2. Install this furnace only in location andposition as specified in pages 7 - 13 ofthese instructions.
3. Provide adequate combustion and ventila-tion air to the furnace space as specified inpages 13 - 20 of these instructions.
4. Combustion products must be dischargedoutdoors, connect this furnace to an ap-proved vent system only, as specified inpages 14-19 of these instructions.
5. Never test for gas leaks with an openflame. Use a commercially available soapsolution made specifically for the detectionof leak to check all connections.
6. Always install furnace to operate within thefurnace’s intended temperature rise rangewith a duct system that has an externalstatic 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 supplyducts carry air circulated by the furnace toareas outside the space containing thefurnace, the return air shall also be handledby duct(s) sealed to the furnace casingand terminating outside the space contain-ing the furnace. Note: This section onlyapplies to furnaces installed with side ortop return air.
8. A gas-fired furnace for installation in aresidential garage must be installed asspecified in page 7 of these instructions.
9. The furnace is not to be used for tempo-rary heat of buildings or structures underconstruction.
M3 series furnaces are air conditioning readyas shipped. The furnace cooling capacities ofthe blower motor speed taps are shown inTable 3. Table 2 lists the shipping weights forthe M3 series furnaces.
OWNER INFORMATIONNORDYNE has been involved in the design ofproducts for the manufactured home industrysince the first manufactured home or trailerwas built.
NORDYNE originated the sealed combustionsystem, which separates the furnace com-bustion system from the living area of thehome, now a standard for the manufacturedhome industry.
NORDYNE engineers developed the first cen-tral heating system and the first central airconditioner for manufactured homes.
NORDYNE is dedicated to bringing to its cus-tomers the finest heating and cooling comfortpossible. NORDYNE constantly seeks to fur-ther refine its products to continuously provideexceptional comfort.
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Follow the instructions in this booklet carefullyand this appliance will provide many years ofsuperior performance.
If you wish to cool your home automaticallywith a central air conditioning system investi-gate the excellent NORDYNE cooling systemsavailable from your heating and cooling con-tractor. These systems are designed to workbest with your NORDYNE furnace and havebeen carefully engineered to deliver optimumperformance when mated with NORDYNEmanufactured home furnaces.
NORDYNE also offers water heaters, fireplacesand ventilating systems specifically designedfor manufactured housing applications. Checkwith your manufactured home retailer, yourheating and cooling contractor or yourdistributor for information. Write directly to thefactory (PO Box 8809, O’Fallon, MO 63366) ifyou are not able to locate a source for NORDYNEmanufactured housing products in your area.
MANUFACTURER WARRANTY, OWNER’SRESPONSIBILITIESIt is the sole responsibility of the homeowner tomake certain the gas furnace has been correctlyset up and converted to the proper fuel (L.P. gasor Natural gas) and adjusted to operate prop-erly. All gas furnaces are manufactured forNatural gas and must be field converted whenusing L.P. gas.
A warranty certificate with full details is includedwith these instructions. However, NORDYNEwill not be responsible for any costs found nec-essary to correct problems due to impropersetup, improper installation, furnace adjustments,improper operating procedure on the part of theuser, etc.
Some specific examples of service calls whichcannot be included in warranty payments are:
1. Converting the furnace to use another typeof gas.
2. Repairing duct work in the home found to befaulty.
3. Correcting wiring problems in the electricalcircuit supplying the furnace.
4. Resetting circuit breakers, blown fuses orother switches.
5. Correcting problems due to improper gassupply pressure to the furnace.
6. Providing instructional training on how tolight and operate the furnace.
7. Furnace problems caused by installation ofan air conditioner, heat pump or other aircomfort devices.
8. Revising installation of the furnace flueassembly.
9. Adjusting or calibrating of thermostat.10. Any construction debris which falls into
the flue system.
Carefully review these responsibilities with yourmanufactured housing dealer, service companyor gas supplier so there will be no misunder-standing at a later time.
! CAUTION:• Never attempt to alter or modify this
furnace or any of its components.• Never attempt to repair damaged or
inoperable components. Such actioncould cause unsafe operation, ex-plosion, fire and/or asphyxiation.
• If a malfunction has occurred, or ifyou feel that the furnace is not oper-ating as it should, contact a qualifiedservice agency or gas utility for as-sistance.
INSTALLATION STANDARDSInstaller shall be familiar with and comply with allcodes and regulations applicable to the installa-tion of these heating appliances and relatedequipment. In lieu of local codes, the installationshall 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, Part3280.707[a][2])
b. The Standard for Manufactured Home Instal-lations (Manufactured Home Sites, Commu-nities, and Set-Ups) ANSI A225.1 and/orCAN/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.
e. American National Standard (ANSI-C1/NFPA-70) and/or CSA 22.1 Canadian Electric CodePart 1 for all electrical field wiring.
7
CE générateur d'air chaud doit être installéconformément aux instructions du fabricant etaux codes locaux. En l'absence de code local,respecter la norme ANSI Z223.,1, institulé Na-tional Fuel Gas Code ou les codes d'installationCAN/GCA-B149.
The National Fuel Gas Code is available bywriting:
American National Standards Institute, Inc.1430 BroadwayNew York, NY 10018
NFPA publications are available by writing:
National Fire Protection AssociationBatterymarch ParkQuincy, ME 02269
LOCATIONThe furnace must be installed on a level sur-face, and as close to the center of the airdistribution system as possible. See Figure 1for overall dimensions to determine the re-quired clearances in hallways, doorways,stairs, etc. to allow the furnace to be moved tothe installation point. The furnace must be in-stalled so that all electrical components areprotected from water.
Minimum clearances to combustible materialsare listed in Table 4. Access for positioning andservicing must be considered when locatingthe unit.
This furnace is certified for use on woodflooring. The furnace must be installed on asolid surface and must be level front-to-backand side-to-side. This furnace must not beinstalled directly on carpeting, tile, or any com-
Table 4. Minimum Clearances
*Note: For 1” clearance, use a fully louvered door with atleast 400 square inches of free airflow area.
CLOSET ALCOVEALL MODELS Inches Inches
Front 1* 1*Back 0 0Sides 0 0Vent 0 0Top 6 6Duct (Plenum)w/ Coil Box 0 0w/o Coil Box 1/4 1/4(within 3 feet)
bustible material other than wood flooring. Thefurnace 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 furnaceswithout the A/C coil box must be installed suchthat surfaces are at least 1/4" from combustiblematerials.
When installed in a residential garage, the fur-nace must be positioned so the burners and thesource of the ignition are located no less than18 inches above the floor and protected fromphysical damage by vehicles.
CIRCULATING AIR SUPPLY
! WARNING:Products of combustion must not beallowed to enter the return air openingsof the furnace or the circulating airsupply. Failure to prevent products ofcombustion from being circulated intothe living space can create potentiallyhazardous conditions including carbonmonoxide poisoning that could result inpersonal injury or death.
The floor or platform on which thefurnace is mounted must provide soundphysical support of the furnace with nogaps, cracks, or sagging between thefurnace and the floor or platform.
The circulating air ductwork must notbe connected to any other heatproducing device such as a fireplaceinsert, stove, etc.
GENERALPlenums and air ducts must be installed inaccordance 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 ConditioningSystems (NFPA No. 90B).
8
Figure 4.
Figure 3.
13 1/4"
10 1/4"
19”
19"
Top Viewof Duct
Connector
x
SUPPLY AIR DUCT
FLOOR CAVITY(depth equal to "X" in Figure 5 and Table 5)
RETURN AIR PROVISIONSU.S.A. home manufacturers shall comply withall of the following conditions to have accept-able return air systems for closet installedforced air heating appliances:a. Regardless of the location, the return air
opening into the closet shall not be less thanspecified in the appliance’s listing.
b. Means shall be provided to prevent inadvert-ent closure by a flat object placed over thereturn air opening when it is located in thefloor of the closet (versus the vertical frontor side wall).
c. Closet installations must use a louvereddoor 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 thelouvered openings in the furnace door. For1” clearance from furnace, use a fully lou-vered door with at least 400 sq. in. of freeairflow area.
d. The cross-sectional area of the return ductsystem leading into the closet, when located
Figure 2. Non-PlatinumSupply Duct System
A Single trunk duct
B Dual trunk ductw/crossover connector
CTransition duct w/branches
Table 5. Duct Connectors
Use Duct ConnectorIf "X" (Floor Cavity) is: Model Part Number:
English Metric (mm ) Finger Tab Screw Down7/8" 22 901987 9040082" 51 901988 904009
4 1/4" 108 901989 9040106 1/4" 150 901990 9040118 1/4" 210 901991 90401210 1/4" 260 901992 90401312 1/4" 311 901993 904014
in the floor or ceiling shall not be less than 235square inches.
e. The total free area of openings in the floor orceiling registers serving the return air ductsystem must be at least 352 sq. in. At leastone register should be located where it is notlikely to be covered by carpeting, boxes andother objects.
f. Materials located in the return duct systemmust have a flame spread classification of200 or less. This includes a closet door if thefurnace is in a closet.
g. Noncombustible pans having 1" upturnedflanges are located beneath openings in afloor duct system.
h. Wiring materials located in the return ductsystem shall conform to Articles 300-22 ofthe National Electrical Code (ANSI C1/NFPA-70).
9
Figure 6. Closet or Alcove
10"
23 -1/4"
FLOOR OPENING
CLCL
ALT. FUELLINE HOLES
SIDE WALLREAR WALL
FUEL LINE HOLE
Figure 5.
X SEE TABLE 5
REDUCER
FELT-SEAL(1)
SPACERS
C
( )OPENING TO DUCT
(1) WITH PLATE (C) REMOVED OPENING BECOMES 13-1/4” x 13-1/4”(2) WITH PLATE (C) REMOVED OPENING BECOMES 13" X 13". WITH REDUCER IT IS 13" X 10-1/8".
(1) FINGER TAB DUCT CONNECTOR ONLY(2) SCREW DOWN DUCT CONNECTOR ONLY
i. Gas piping is not run in or through the returnduct system.
j. Test the negative pressure in the closet withthe air-circulating fan operating at high speedand the closet closed. The negativepressure is to be no more negative thanminus 0.05 inch water column.
k. For floor return systems, the manufacturedhome manufacturer shall affix a prominentmarking on or near the appliance where itcan be easily read when the closet door isopen. The marking shall read:
! CAUTION:HAZARD OF ASPHYXIATION: Do notcover or restrict return air opening.
l. Air conditioning systems may require moreduct register and open louver area to ob-
tain necessary airflow. Use NORDYNE’scertiduct program to determine proper ductsize for A/C.
DUCTED RETURN AIR
M3 furnaces with model numbers ending in AWor BW are factory configured for the return airto flow through the front louvered door. Thereturn air may also be attached to either side orthe top of the furnace cabinet using a fieldinstalled kit. Refer to Table 12 for the NORDYNEducted return kit P/N number. The location andsize of the side and top return air connectionsare shown in Figure 1. The filter size for the sidereturn air is 20” x 20” x 1”. For top return thefilter size is 24” x 16” x 1”.
M3 furnaces with model numbers ending inBWT are factory configured for the return air toenter the top of the furnace.
10
Figure 7. Cut-Out Locations
2-3/4
2
1-3/4
17-29/32
21-7/16
1-3/4
3-19/32
14-1/2
14-1/2
2-1/4
23-1/4
12-7/8
14-3/4
20
24 21-3/4
10
15-1/2
˚ALT FUEL LINE
ENTRY
1-1/4
VENT
FUEL LINE ENTRY
FURNACEOUTER DOOR
FLOOR CUT-OUTFOR DUCT CONNECTIONS
FLOOR CUT-OUTFOR OPTIONALCOOLING COIL
FOR NON-PLATINUMSERIES UNITS
FU
RN
AC
E O
UT
LIN
E
REAR WALL OF CLOSET OR ALCOVE
COMBUSTION AIR INTAKE
AIR DISTRIBUTION SYSTEMSFor proper air distribution, the supply ductsystem must be designed so that the staticpressure measured external to the furnacedoes not exceed the listed static pressurerating shown on the furnace rating plate.
Three typical distribution systems are illus-trated in Figure 2. Location, size, and numberof registers should be selected on the basis ofbest air distribution and floor plan of the home.
DUCT CONNECTOR SELECTIONPLATINUM SERIES
a. For Platinum ready construction usethe 14” round plenum, p/n: 903896.
NON-PLATINUM SERIES
a. Determine depth of floor cavity fromsurface of floor to top of supply air duct(See Figure 3).
b. Select appropriate model from Table 5which matches X-dimension of the floor
cavity. To maximize air delivery, re-move reducer “C” (see Figure 5) toobtain the largest open area that will fitthe duct/floor construction.
DUCT INSTALLATIONRequired 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.
CUT OUT FLOOR OPENING & FUEL LINEHOLEa. 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 ofcenter of the floor cut-out (See Figure 6) or
11
Figure 9. Duct Connector
Screw DownDuct Connectors Platinum Series
Figure 8. Mounting Plate
REAR WALL
SUPPLY AIR DUCT
FUEL LINE HOLES
MOUNTING PLATE
FLOOR OPENING
BEND CONNECTOR TABSUNDER DUCT OPENING
5-1/4" to the left of center of the floor cut-out,or for entry through right-side of furnacemeasured 9" to the right of center of the floorcut-out.
d. Cut out floor opening and one gas line hole.
CUT DUCT OPENING (FINGER TABBEDONLY)a. Place duct connector through the floor open-
ing with bottom tabs resting on top of thesupply air duct.
b. Center duct connector and push back againstrear edge of floor opening.
c. Mark cut-out location (tab area) and removeduct connector.
d. Cut out duct opening 1/16" larger than areamarked.
INSTALL FURNACE MOUNTING PLATEa. Place mounting plate (supplied within duct
connector) at rear of the floor opening (SeeFigure 9).
INSTALLING PLATINUM SERIES 14”ROUND DUCT CONNECTORa. Place duct connector through the floor open-
ing. (See Figure 9).b. Secure duct connector to floor.
INSTALLING SCREW DOWN DUCT CON-NECTORa. 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 andcarefully lower screw down duct connectorinto place.
c. Once duct connector is located on duct,temporarily hold in place while fastening ductconnector to the floor using flat head screwsor nails. Be sure flanges of duct connectorstay in contact with the duct.
d. Screw plenum to duct making sure a seal ismade between the duct and the duct con-
Finger TabbedDuct Connectors
14” SUPPLYCONNECTION
FUELLINE
HOLES
SCREWS
MOUNTINGPLATE
PLENUM
SUPPLY AIR DUCT
FUEL LINE HOLES
MOUNTING PLATE
FLOOR OPENING
SCREWS
REAR WALLMOUNTING PLATE
FLOOR OPENING
FUEL LINE HOLES
SUPPLY AIR DUCT
12
TABS TABS
DUCT DUCT
1. INSERT DUCT PLENUM CONNECTOR INTO DUCT CUT-OUT.
2. BEND BOTTOM TABS OVER AND ONTO THE UNDERNEATH DUCT SERVICE.
Staple Folded DuctFlap (typ) to side of Duct
Connector
DuctSTEP 4.
STEP 1.
"A" "A"
"B"
"B" Cut- Out Area"A"
Cut- Out Area "A"
Fold Back Flap "B"
Fold Back Flap "B"
Top of Duct
"A" "A"
STEP 2.
"B"
"B"
Fold Back Flap"B"
CutLines Duct
Fold Back Flap"B"
STEP 3.
Bend Duct Connector Tabs Upand Over- (along length of duct)
DuctFlap "B"
Duct
Duct
Duct Connector
Narrow Duct
Figure 12. Alternate Installation
Figure 11. Narrow Duct Installation
Figure 10. Installation of Duct Connector
nector. Additional screws may be added ifrequired.
e. Cut away along edge of flange allowing thecenter to drop into the duct. Remove sectionof duct with caution, as edges will be sharp.
INSTALLING FINGER TABBED DUCT CON-NECTORSa. Place duct connector through the floor open-
ing with bottom tabs extending through theduct opening. (See Figure 9)
b. Secure duct connector to floor.c. Bend bottom tabs under and up tightly against
the supply air duct (See Figure 10).
NOTE: The duct connector is designed for useon ducts 12" in width. When using the connec-tor on 12" wide ducts, there may be insufficientclearance to bend the tabs on two sides of theduct connector. In such cases the tabs may be
attached to the sides of the duct by using sheetmetal screws or other suitable fasteners. (SeeFigure 11).
If sealant, mastic, or tape is used to provide abetter seal, it should be approved by applicablenational or local codes.
ALTERNATE ATTACHMENT METHODS
This procedure may also be used to install afurnace duct connector to narrow metalductwork where insufficient clearance preventsbending of the duct connector tabs at theside(s) of the duct. (See Figure 12).1. Score and cut the top of the metal duct as
indicated in Step 1 or Step 2. With Step 1choice, also cut out the metal from the shadedarea “A”.
2. Fold the duct flap “B” up, (See Step 3).
13
MTG. PLATE TABSSLIDE FURNACE
ALL THE WAY BACK ONTO MTG. PLATE
SUPPLY AIR DUCT
Knockout Over Holes
SECURE FURNACE WITH 2 FASTENERS AT FRONT
CORNER HOLES
SUPPLY AIR DUCT
FUELLINEHOLES
MTG. PLATE TABSSLIDE FURNACE
ALL THE WAY BACK ONTO MTG. PLATE
SECURE FURNACE WITH 2 FASTENERS
AT FRONT CORNER HOLES
Figure 13. “A”, “B”, & PlatinumCabinet Furnaces
Figure 14. “A” Cabinet Furnace on 911969Coil Cabinet (Non-Platinum Series)
3. At the front-to-back of duct run (Area “A”),bend the duct tabs and secure them directlyto the duct.
4. At Area “B”, bend the duct tabs up and backover, around the duct connector, (SeeStep 3).
5. Fold/form the duct flap against the side of theduct connector and attach as shown, (SeeStep 4). Use three (3) staples (minimum) oneach duct flap OR, if a 2X block/joist is notprovided, use two (2) sheet metal screws(minimum) on each duct flap. An alternateattachment method is acceptable, as longas the plenum is securely attached.
6. Tape the duct flap edges with an approvedtape for a leak-free joint.
INSTALL FURNACEa. 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 mountingplate tabs.)
d. Secure front with one (1) fastener at eachcorner (See Figure 13 or 14).
NOTE: Additional fasteners may be used atrear, sides or through door frame, as desired,to secure furnace to closet or alcove framing.
VENTING AND COMBUSTION AIRREQUIREMENTS
! CAUTION:Snow must not be allowed to restrict orblock the combustion air intake or ventpipes.
GeneralNORDYNE condensing furnaces must beinstalled with outdoor combustion air pipeddirectly to the furnace. Codes refer to thistype of installation as direct vent, or two pipeinstallation.
Provisions must be made for adequate supplyof air for combustion and ventilation. ForUnited States installations, the adequacy ofair provisions can be determined by consultingthe current version of the National Fuel GasCode (ANSI Z223.1/NPFA-54). For Canadianinstallations, requirements are specified in theNational Standard of Canada (CAN/CGAB149.1 & .2). Consult local codes for specialrequirements.
NOTE: If the furnace is operated withoutadequate air for combustion and ventilation, itmay not perform properly. Furnacecomponents may be strained by hightemperature and could fail prematurely.
! WARNING:The combustion air piping must not beblocked or restricted in any manner.
! WARNING:Furnace installation using methodsother than those described in thefollowing sections must comply with theNational Fuel Gas Code and allapplicable local codes to providesufficient combustion air for the furnace.
14
! CAUTION:Do not allow debris to fall into the fur-nace. This could cause unsafe opera-tion and voids the furnace warranty.
VENTING REQUIREMENTS
! WARNING:FURNACE MUST NOT BE COMMONVENTED WITH OTHER APPLIANCES.
GeneralThis section specifies installation requirementsfor 2-pipe combustion air piping. The capacitytable provided in this section applies to themaximum equivalent lengths of vent andcombustion air intake pipe.
These condensing furnaces are classified as"Category IV" appliances, which requirespecial venting materials and installationprocedures. Category IV appliances operatewith positive vent pressure and thereforerequire vent systems which are thoroughlysealed. They also produce combustioncondensate, which is slightly acidic and cancause severe corrosion of ordinary ventingmaterials. Furnace operation can be adverselyaffected by restrictive vent and combustionair piping. Therefore, vent and combustion airpiping lengths must conform completely to therequirements of Table 6.
The furnace must be vented to the outdoors.
! WARNING:
CARBON MONOXIDE POISONINGHAZARD
1. Seal any unused openings in theventing system
2. Inspect the venting system forproper size and horizontal pitch,as required in the National FuelGas Code, ANSI Z223.1 or theCAN/CGA B149 Installation Codesand these instructions. Determine
that there is no blockage or re-striction, leakage, corrosion andother deficiencies which couldcause an unsafe condition.
3. So far as is practical, close allbuilding doors and windows andall doors between the space inwhich the appliance(s) connectedto the venting system are locatedand other spaces of the building.
4. Follow the lighting instructions.Place the appliance beinginspected in operation. Adjustthermostat so appliance shalloperate continuously.
5. Turn on clothes dryers and anyother appliance not connected tothe venting system. Turn on anyexhaust fans, such as range hoodsand bathroom exhausts, so theyshall operate at maximum speed.Do not operate a summer exhaustfan.
6. Close fireplace dampers.7. Test for spillage from draft hood
equipped appliance at the drafthood relief opening after 5 minutesof main burner operation. Use theflame of a match or candle.
8. If improper venting is observedduring any of the above tests, theventing system must be correctedin accordance with the NationalFuel Gas Code, ANSI Z223.1/NFPA54 and/or CSA B149.1, Natural Gasand Propane Installation Codes.
9. After it has been determined thateach appliance connected to theventing system properly ventswhen tested as outlined above,return doors, windows, exhaustfans, fireplace dampers and anyother gas burning appliance totheir previous conditions of use.
It must not be vented in common with anyother appliance, even if that appliance is of thecondensing type. Common venting can resultin severe corrosion of other appliances or theirventing and can allow combustion gases to
15
*NOTES1. Subtract 3.5 ft. for each additional 3" 90 degree elbow.2. Two 45 degree elbows are equivalent to one 90 degree elbow.3. One short radius elbow is equivalent to two long radius
elbows.4. Do not include termination elbows in calculation of vent length.5. This table is applicable for elevations from sea level to 4000
ft. For higher elevations, decrease vent pipe lengths by 8% per1000 ft. of altitude.
6. Only the above pipe materials are approved for use with thesecondensing furnaces.
PVC,CPVC or ABS Inlet/Outlet
SCH. 40 Pipe Size 3" 3"Model M3RL 060 50 50Model M3RL 080 50 50
APPLICATION
MAXIMUMDIRECT VENT, DUAL PIPE LENGTH (ft.)*
Table 6. Vent Table
VENT TERMINAL AIR SUPPLY INLET AREA WHERE TERMINAL IS NOT PERMITTED
1 In accordance with the current CSA B149.1 Natural Gas and Propane Installation Code2 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.‡ 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 themanufacturer’s installation instructions.”
Canadian Installations 1 US Installations 2
A = Clearance above grade, veranda, porch, deck, or balcony
12 inches (30 cm) 12 inches (30 cm)
B = Clearance to window or door that may be opened
6 inches (15 cm) for appliances ≤ 10,000 Btuh (3 kW), 12 inches (30 cm) for appliances > 10,000 Btuh (3 kW) and ≤ 100,00 Btuh (30 kW), 36 inches (91 cm) for appliances >100,00 Btuh (30 kW)
6 inches (15 cm) for appliances ≤ 10,000 Btuh (3 kW), 9 inches (23 cm) for appliances > 10,000 Btuh (3 kW) and ≤ 50,000 Btuh (15 kW), 12 inches (30 cm) for appliances > 50,000 Btuh (15 kW)
C = Clearance to permanently closed window * *D = 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
* *
E = Clearance to unventilated soffit * *F = Clearance to outside corner * *G = Clearance to inside corner * *H = Clearance to each side of center line
extended above meter/regulator assembly3 feet (91 cm) within a height 15 feet above the meter/regulator assembly
*
I = Clearance to service regulator vent outlet 3 feet (1.83 m) *J = Clearance to nonmechanical air supply inlet
to building or the combustion air inlet to any other appliance
6 inches (15 cm) for appliances ≤ 10,000 Btuh (3 kW), 12 inches (30 cm) for appliances > 10,000 Btuh (3 kW) and ≤ 100,00 Btuh (30 kW), 36 inches (91 cm) for appliances >100,00 Btuh (30 kW)
6 inches (15 cm) for appliances ≤ 10,000 Btuh (3 kW), 9 inches (23 cm) for appliances > 10,000 Btuh (3 kW) and ≤ 50,000 Btuh (15 kW), 12 inches (30 cm) for appliances > 50,000 Btuh (15 kW)
K = Clearance to a mechanical air supply inlet 6 feet (1.83 m) 3 feet (91 cm) above if within 10 feet (3 m) horizontally
L = Clearance above paved sidewalk or paved driveway located on public property
7 feet (2.13 m) †*
M = Clearance under veranda, porch deck, or balcony
12 inches (30 cm) ‡*
Figure 15. Vent Termination Clearances for Direct Vent Furnaces
16
escape through such appliances or vents. Donot vent the furnace to a fireplace chimney orbuilding chase.
If removing an existing furnace in a ventingsystem, the venting system may not be properlysized. To test the vent system with the remainingappliances, follow the test outlined below.
The following steps shall be followed with eachappliance connected to the venting systemplaced in operation, while any other appliancesconnected to the venting system are not inoperation:
Vent Pipe MaterialVent and combustion air pipe and fittings mustbe one of the following materials and mustconform to the indicated ANSI/ASTM standards:
Material StandardSchedule 40 PVC D1785
PVC-DWV D2665SDR-21 D2241
& SDR-26ABS-DWV D2661
Schedule 40 ABS F628Foam/Cellular Core PVC F891
Cement and primer must conform to ATSMStandard D2564 for PVC and Standard D2235for ABS. When joining PVC piping to ABS, usean appropriate solvent cement and procedureper the piping manufacturer's recommendationand ASTM Standard D3138.
Vent Pipe InstallationPipe Routing and SupportRoute piping as directly as possible betweenthe furnace and the outdoors and rememberthat routing affects pipe length limitations perTable 6. Locate the combustion air intake andthe vent exhaust in the same atmosphericpressure zone - i.e. both must exit the buildingthough the same portion of exterior wall orroof. Vent piping must be sloped upwards notless than 1/4" per foot in the direction from thefurnace to the terminal. This is to ensure thatany condensate flows back to the furnacewhere it can be disposed of through thecondensate disposal system.
! CAUTION:Combustion air must not be drawn fromoccupied spaces and a corrosiveatmosphere.
The quality of outdoor air must also beconsidered. Be sure that the combustion airintake is not located near a source of solventfumes or other chemicals which can causecorrosion of the furnace combustion system.
Piping must be mechanically supported so thatits weight does not bear down on the furnace.Supports must be at intervals no greater thanfive feet, and at smaller intervals if necessaryto ensure that there are no sagging sectionsto trap water (See Figures 16 & 17).
These condensing furnaces have beencertified for installation with zero clearancebetween vent piping and combustible surfaces.However, it is good practice to allow space forconvenience in installation and service.
Location of Outdoor TerminationsVent and combustion air intake terminationsmust be located to ensure proper furnaceoperation and to conform to applicable codes.Figure 15 illustrates necessary distances fromthe vent termination to windows and buildingair intakes. In Canada, the Canadian FuelGas Code takes precedence over theseinstructions. Specifically, all minimumdistance requirements with respect totermination of the vent piping listed below.
The following list is a summary of vent terminallocation requirements:1. The termination must be 12 inches above
snow level or grade level whichever ishigher. See Figure 18 for alternate methodto 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 of3 ft. above any forced air inlet within 10 ft.
4. The vent termination shall be located atleast 4 ft. horizontally from any electricmeter, gas meter, regulator and any reliefequipment. These distances apply ONLYto U.S. installations. In Canada, the Cana-dian Fuel Gas Code takes precedence.
17
Figure 16. Horizontal Venting
Downflow Furnace
Seal/CaulkAround Pipeat Building
90˚ Elbow
12"Min.
Normal Snow Level
Wall
Coupling
First Support Should be as Close toFurnace Connection as Possible
Combustion AirIntake Pipe Furnace
3" x 2"Reducer
ExhaustVentPVC orABS pipe
Offset with Vent for AdequateDimensional Clearance
3 1/
2"
See Vent Table 4
Straps or Other SuitableSupports at Minimum of
5 ft. Intervals
Upward Pitch - 1/4" Per FootOutlet Exhaust Vent
Top View
6"
3 9/16"1 7/8"
Vent
CombustionAir Intake Pipe
Figure 17. Vertical Venting
Upward Pitch1/4" per foot
Vent
First support should be as close to furnace as possible
Combustion Air Intake Pipe
5'Combustion AirIntake Pipe
Vent
Support Systemon Vertical Rise
Below Joints
5. Avoid areas where condensate drainagemay cause problems by dropping on plant-ers or patios, etc. Also ensure that ex-haust gases will not impinge on windowsor building surfaces, which may be com-promised or damaged by condensation.Do not install the vent terminal such thatexhaust is directed into window wells,stairwells, under decks or into alcoves orsimilar recessed areas, and do not termi-nate above any public walkways.
6. Select the point of wall penetration wherethe minimum 1/4 inch per foot of slope upcan be maintained.
! CAUTION:For optimal performance vent furnacethrough wall which experiences the leastexposure to winter winds.
18
Horizontal VentingVent and combustion air intake terminationsmust be as shown in Figure 19 unless theconcentric vent termination kit is used.
! WARNING:Ensure that the combustion air vent andthe exhaust vent are configured asshown in Fig. 19. Improper venttermination can cause recirculation ofthe flue gases. This may result in furnacevibration. In severe cases, the furnacewill cycle, due to the intermittent contactbetween the flame and the flame sensor.If you note these oscillations occurring,check the vent configuration. Make surethat the exhaust vent does not have a 90degree termination.
For horizontal venting, either the HorizontalExterior Vent Mounting Kit or the ConcentricVent Termination Kit may be used (See Table12).
For Canadian installations please refer to theCanadian Installation Code (CAN/CGA-B149.1or 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 sizedclosely to the pipe diameter must first be cutthrough the wall. A short length of pipe is thencut such that it can penetrate the wall and beheld in place by closely fitting standard cou-plings. The face plates are retained on bothsides of the wall by the couplings, and thegasket is retained against the wall by the outerface plate. Face plates must be fastened to thewall and the outside one must be flashed asappropriate to prevent entry of water.
When the above kits are not used the followingsteps are required:1. Check the hole size cut through the exte-
rior wall. Insure that the hole diameter isless than the diameter of the couplings tobe used.
2. Extend the vent pipe through the wallapproximately 1" and seal the area be-tween the wall and pipe.
3. Apply couplings to the vent pipe on theinterior and exterior sides of the wall toinsure the pipe can not be pushed or pulledthrough the wall.
4. Insure the combustion air inlet pipe has a 90degree termination elbow, and is pointingdownward as shown in Figures 19 & 20.
Note that a combustion air intake must beprovided with an elbow opening downward.
When the vent pipe must exit an exterior wallclose to the grade or expected snow level, ariser should be provided as shown in Figure 18.Insulation is required to prevent freezing of thissection of pipe.
Vertical VentingFor vertical venting, either the configurationshown in Figure 20 or the Concentric VentTermination Kit may be used. Vertical venting isone of the shortest routing methods whenpiping vents for furnaces. The M3 furnaceoperates trouble-free when the furnace is in-stalled with a shorter vent.• The inlet for the combustion intake pipe must
be extended at least one foot above the rooflineor snow accumulation level.
• The outlet of the vent must be extended at least10 inches above the inlet of the combustion airintake pipe.
• The vent as well as the combustion air intakepipe should be located on the same side of theroof. Both pipes must not be closer than 5inches apart. They should not be separatedmore than 36 inches.
The roof penetration must be properly flashedand waterproofed with a plumbing roof boot orequivalent flashing. Termination spacing re-quirements from the roof and from each othermust be per Figure 20.
Concentric Vent TerminationA concentric vent termination is approved foruse with these furnaces (See Table 12). Forproper installation of the concentric vent termi-nation, follow the installation instructions pro-vided with the kit.
19
36" max.12" min.
Exhaust VentOption B
Exhaust VentOption A
Exhaust VentOption C
Mounting KitFaceplate Secured
to Wall with Screws 12" Min.36" Max.
12" Min.36" Max.
7" Min.
8" Min.
12" Min. toNormal Snow Level
CombustionAir Inlet
Grade Levelor NormalSnow
Inlet Exhaust
Figure 20. Vertical Vent Termination
A= 12" Above Roof orSnow Accumulation Level
Figure 19. Exhaust and Combustion AirPipe Clearances
Elbow
ExhaustVent
Exhaust
Plumbing VentRoof Boot(Typ. Both Pipes)
A
1"
5" Min.36" Max.
10" Min.
Combustion Air Intake
Figure 18. Alternate HorizontalVent Installation
OutsideWall
Support
Vent Configuration toProvide 12" Minimumheight above Snow Level.
1/2" ArmaflexInsulation orEquivalent(if required)
12" AboveNormallyExpectedSnowLevel
12" Min.19" Max.
DRAINAGE OF CONDENSATEFROM FURNACE
! WARNING:The condensate produced by the furnacemust be drained. Do not connect a watersupply to the drainage hose of thefurnace.
NOTE: The condensate drain should be pro-tected from freezing when in unheated spaces.
The furnace is supplied with an internal conden-sate drain trap.
! CAUTION:Do not install additional traps in thecondensate drain.
The condensate drain may exit through the leftside panel, the right side panel, or through theleft or right hole on the bottom panel. (See Figure21). Ensure that the flexible drain hose is notkinked.
The condensate should drain from the plasticcollector box (location A in Figure 21) as drop-lets or a small stream. If you notice the furnacehas operated for more than 5 minutes withoutdraining or the red status light on the controlboard is pulsing a 2-blink code follow the stepsbelow.
Note: If terminations meet-ing these vertical require-ments exceed the maximumheight for safe transit, thevent and combustion air in-takes may be shipped withthe home for assembly onsite. The furnace must belabeled to notify the installer/user not to use the furnaceuntil the vent and combus-tion air intake terminationsare installed.
20
Figure 21. Furnace with Condensate Drain Trap Assembly
A
A
Clamp
Step 1: LoosenStep 2: Rotate to drain directionStep 3: Retighten
KeepDownwardSlope
Alt. DrainAlt. DrainAlt. DrainAlt. Drain
Floor Ca vity
Floor
“Hard”J Drain Tube
BurnerBox
CollectorBox
1. Remove the collector box soft tube atlocation A in Figure 21 and insure the exitfrom the collector box is clear of anydebris or obstructions.
2. Replace this tube and insure the fit to theheader spout is air tight. Air will be drawn intothe header if this connection is not tight.
3. Check other tube connections along thedrain system. Insure that all are air tight.
NOTE: Industry research studies indicate thatwhen condensate is routed to an active drain,household detergents, etc., buffer its acidity. Ifthe drain is not actively used or if codes require,obtain a neutralizer kit (See Table 12). Properdrains and connections to the condensate tub-ing are required as NORDYNE cannot be heldresponsible for water leakage which occursdue to loose hose connections or improperlysealed drain line pipes.
GAS SUPPLY AND PIPING
GeneralThis furnace is equipped for bottom, left, orright side gas entry. Typical gas service hook-ups are shown in Figure 22. When making thegas connection provide clearance between thegas supply line and the entry hole in the furnacecasing to avoid unwanted noise and/or damageto the furnace.
All gas piping must be installed in compliancewith local codes and utility regulations. Somelocal regulations require the installation of a manualmain shut-off valve and ground joint union exter-nal to the furnace. The shut-off valve should be
readily accessible for service and/or emer-gency use. Consult the local utility or gassupplier for additional requirements regardingplacement of the manual main gas shut-off. Inthe absence of local codes, the gas line instal-lation must comply with the provisions stated inthe Federal Manufactured Home Standard(H.U.D Title 24, part 280) and the National FuelGas Code (ANSI Z223.1/NFPA-54) or (CAN/CGA B149) installation codes.
A drip leg should be installed in the vertical piperun to the unit. Table 7 lists gas flow capacitiesfor standard pipe sizes as a function of lengthin typical applications based on nominal pres-sure drop in the line.
NOTE: Gas piping must not be run in or throughair ducts, gas vents, etc.
Compounds used on threaded joints of gaspiping must be resistant to the actions of lique-fied petroleum gases.
! CAUTION:Do not use matches, lighters, candles,or other sources of open flame to checkfor gas leaks.
NOTE: When pressure testing gas supplylines at pressures greater than 1/2 psig (14 in.water column), the furnace must be discon-nected from the gas supply piping system toprevent damage to the gas control valve.
21
Figure 22. Typical Gas Piping
Table 7. Capacity of Black Iron Gas Pipe (cu. ft. per hour) for Natural Gas
(specific gravity = .60)
To Gas Supply
Floor
Inducer
Alt. GasLine Entry
Floor Cavity
GasValve
BurnerBox
ControlBoard
MainBlower
NOMINAL LENGTH OF PIPE RUNBLACK IRON (feet)
PIPE DIAMETER(in.) 10 20 30 40 50 60 70 801/2 130 90 75 65 55 50 45 403/4 280 190 150 130 115 105 95 901 520 350 285 245 215 195 180 170
1 1/4 1050 730 590 500 440 400 370 3501 1/2 1600 1100 890 760 670 610 560 530
CAPACITY OF BLACK IRON GAS PIPE (CU. FT. PER HOUR)FOR NATURAL GAS (SPECIFIC GRAVITY - 0.60)
The cubic feet per hour listed in the table above must be greater thanthe cubic feet per hour of gas flow required by the furnace.
To determine the cubic feet per hour of gas flow required by the furnace,divide the input rate of the furnace by the heating value of the gas:
Cubic Feet Input To Furnace (Btu/hr)Per Hour Required Heating Value of Gas (Btu/Cu. Ft.)=
If the test pressure is less than or equal to 1/2psig (14 in. water column), the furnace must beisolated from the gas supply line by closing themanual shut-off valve.
Leak CheckAfter the gas piping to the furnace is complete,all connections must be tested for gas leaks. Tocheck for leaks use only a soap and water solu-tion or other approved method.
High Altitude DerateThe nameplate input rating for the furnacesapply for elevations up to 4,000 feet above sealevel for US and Canada. If the elevation for thefurnace location is higher than 4,000 feet abovesea level, the furnace input must be derated byusing the appropriate orifice size listed inTable 8.
NOTE: The density of air decreases with in-creasing elevation above sea level. This re-duces the quantity of combustion air drawn intothe furnace under normal operation and requiresthe unit be derated by using smaller gas orificesor lower manifold pressure.
CONVERSIONThis furnace can be converted from the fac-tory-equipped gas to either natural gas (for LPgas ready models), or LP gas (for natural gasready models). Conversions must be made byqualified service personnel, using only factoryauthorized or approved parts. The requiredconversion orifices are supplied with the fur-nace.
! WARNING:DO NOT REMOVE OR DEFACE THEORIGINAL RATING PLATE.
! CAUTION:The gas supply shall be shut off prior todisconnecting the electrical power,before proceeding with the conversion.
To Turn Off Fuel Supply to the Appliance:
1. Set the room thermostat to “OFF” or itslowest temperature setting.
2. Turn OFF the main gas supply to the appli-ance at the manual valve, outside of theappliance casing.
3. Remove the control access panel / lou-vered door.
4. Move the appliance gas valve lever/knob tothe “OFF” position.
5. Turn OFF the electrical power to the appli-ance.
22
Table 8. Approximate Orifice Size for Natural and LP Gases
Nat LP Nat LP Nat LP Nat LP Nat LP
060A-A/BW 60,000 4 50 57 50 57 51 58 51 58 52 59
080A-A/BW 80,000 5 49 1.15 mm 49 1.15 mm 50 57 50 57 51 58
Furnace Model Number
M3RL -
Furnace RatingPlate Input
(Btuh)
No. ofBurners
Elevation0 - 2000
Elevation2000-4000
Elevation4000-6000
Elevation6000-8000
Elevation8000-10000
To Remove the Burner Assembly:
1. Follow the instructions “To Turn Off theFuel Supply to the Appliance.”
2. Disconnect the flame sensor wire from theburner box.
3. Disconnect the ignitor wires at the 2 pinplug. This is a locking quick connect andboth sides of the lower section must bedepressed in order to be separated.
4. Remove the wires from the terminals ofthe gas valve.
5. Disconnect the rubber pressure tubesfrom the gas valve and the burner box.
6. Remove the burner access cover platefrom the burner box.
7. Remove supply gas piping from the gasvalve.
8. Carefully remove the burner assembly fas-teners and remove the burner assemblyfrom the appliance. Keep the fasteners thatwere removed. Note that the burner box mayhave hooks near the top and on the right andleft hand sides. To remove this type of burnerbox, lift the burner box upwards and thenremove the box from the unit.
To Remove the Burner Orifices:
1. Remove the four (4) fasteners that securethe gas manifold to the burner box, asshown in Figure 25. Carefully remove thegas manifold assembly from the burnerbox. Note that the gas manifold assemblyconsists of the gas valve, the gas manifold,and the orifices.
2. Carefully remove the burner orifices from thegas manifold, as shown in Figure 25.
! CAUTION:Caution: Do not re-drill the burnerorifices. If the orifice size must bechanged, use only new orifices.
Note: The size of the new orifices that will beinstalled into the unit will depend upon thetype of conversion (sea level or high altitude;natural gas or LP gas).
To Convert the Unit to the Alternate Gas
1. Remove the orifice bag from the manifoldof the unit.
2. Install the appropriate gas burner orificesinto the gas manifold. Remember if in-stalling at altitudes above 4,000 feet toinstall the proper orifices, shown in Table8. When installing the new orifices, DONOT use pipe joint compound on theorifice threads. Screw the orifices into themanifold by hand until snug to eliminatecross threading, then tighten with awrench. Before installing an orifice, checkthe face or side of the orifice for the drillnumber to ensure that it is the appropriatesize.
3. For the conversion to the alternate fuel,the gas valve regulator cap must be turnedover, as shown in Figure 23. You willunscrew the cap and reinstall for your in-stallation. After reinstalling the cap, you willbe able to read "NAT" for the conversion tonatural gas or "LP for the conversion to LPgas.
23
Figure 25. Typical Installation For SealedBurner Box With Access Cover Plate
Burner Orifices Gas
Manifold FlameObservation
Port
GasValve
AccessCoverPlate
BurnerBox
InletPressureTap Inlet
On/Off Lever
Figure 24. Burner Inspection
Figure 23. Convertible PressureRegulator Cap
HoneywellValve
PRESSURE REGULATOR CAP
M11678
NAT N
AT
L
P
L
P
NAT N
AT
OR
OTHER SIDEOF CAP
Reinstalling the Burner Assembly:
1. Reinstall the gas manifold assembly to theburner box with the four (4) fasteners,which were removed earlier.
2. Carefully reinstall the burner box into theunit. After installing the burner, inspectthe alignment of the burners with the heatexchanger tubes. The center of the burn-ers should be aligned with the center of thetubes.
3. Reconnect the gas piping to the gas valve.4. Reconnect the wires to the gas valve termi-
nals.5. Reconnect the rubber pressure tubes to the
gas valve and the burner box. Reinstall theburner access cover plate.
6. Reconnect the ignitor at the 2 positionplug.
7. Reconnect the flame sensor wire to theburner box.
Pressure Gauge Installation
NOTE: For natural gas installations, the in-coming gas line pressure at the gas valve inletmust be between 4.5” WC and 10.0” WC. ForLP gas installations, the incoming gas line pres-sure at the gas valve inlet must be between11.0” WC and 14.0” WC. This pressure can bechecked at the inlet end of the gas valve usinga pressure gauge or U-tube manometer, whichmust be installed according to themanufacturer’s supplied instructions.
LIGHTING AND ADJUSTMENT OFTHE APPLIANCE
1. Turn ON the gas at the manual valve,outside of the unit.
2. Check all gas connections for leaks witha soap and water solution. If the solutionbubbles there is a gas leak which must becorrected. Do NOT use an open flame tocheck for gas leaks.
3. Turn ON the electrical power to the appli-ance.
4. Move the gas valve lever/knob to the “ON”position. The lever/knob must be movedto the end of its range of motion to insurethe valve is completely open. Use onlyyour hand to push in or turn the gas controlvalve. Never use tools.
5. Set the room thermostat to a point aboveroom temperature to begin the heatingcycle of the unit.
6. Check that the unit ignites and operatesproperly. Refer to the installation instruc-tions provided with your unit for the normaloperating sequence.
24
7. After the flame ignites, visually inspect theburner assembly to ensure that the flameis drawn directly into the center of the heatexchanger tube, as shown in Figure 23.The end of the flame will be out of sightaround the bend of the heat exchangertube. In a properly adjusted burner assem-bly, the flame color should be blue withsome light yellow streaks near the outerportions of the flame.
NOTE: Until all of the air is bled out of the gasline, the hot surface ignitor may not ignite the gas.If the ignition control locks out, turn the thermostatto its lowest setting and wait one minute then turnthe thermostat to a point above room temperatureand the ignitor will try again to ignite the mainburners. This process may have to be repeatedseveral times before the burners will ignite. Oncethe burners are lit, check all gas connections forleaks again with the soap and water solution. Ifthe solution bubbles there is a gas leak whichmust be corrected. Do not use an open flame tocheck for gas leaks.
Manifold Pressure
The gas valve for the M3 furnace series isequipped with a special conversion pres-sure regulator cap. The pressure regulatorcap is factory set. If the gas valve is con-verted from natural gas to propane gas orvise versa, the manifold pressure of the gasvalve will be set to pressure listed in Table 9.
COMPLETING THE CONVERSION
1. Affix the gas valve conversion label foundin the package with the orifices to the unitrating plate.
2. Run the appliance through a completecycle to assure proper operation.
! CAUTION:To avoid electric shock, personalinjury, or death, turn off the power atthe disconnect or the main servicepanel before making any electricalconnections.
ELECTRICAL WIRING
GeneralElectrical connections must be made in accor-dance with all applicable local codes and ordi-nances, and with the current revision of theNational Electric Code (ANSI/NFPA 70).
For Canadian installations electrical connec-tions and grounding must be done in accor-dance with the current Canadian ElectricalCode (CSA C22.1 Part 1) and/or local codes. Ifany of the original wire as supplied with thefurnace must be replaced, it must be replacedwith wire having a minimum temperature ratingof 105°C. Refer to the furnace nameplate andTable 8 for electrical requirements.
Line Voltage WiringThe line voltage (115 volt) to the furnace mustbe supplied from a dedicated branch circuitcontaining the correct fuse or circuit breakerfor the furnace. See Table 10. An electricalswitch should be readily accessible from andwithin sight of the furnace. See the WiringDiagram label in the furnace for more details.
The furnace cabinet must have an uninter-rupted, unbroken ground to minimize injuryshould an electrical fault condition occur. Thecontrols used in this furnace require an earthground to operate properly. Acceptable meth-ods for grounding are electrical wire or conduitapproved for electrical ground service. Do notuse gas piping as an electrical ground.
NOTE: Proper line voltage polarity must bemaintained in order for the control system tooperate correctly. Verify that the incoming neu-
Table 9. Manifold Pressure
Type of Fuel Manifold PressureIn. WC
Natural Gas: 3.5Propane (LP) Gas: 10.0
25
Field Supplied Disconnect Within Sight of Furnace
Field SuppliedPanel Connector
Field SuppliedFused Service
Panel
Black (Hot)White (Neutral)Green or Bare
(Ground)
BlackWhite
BlackWhite
BlackWhite
Field Line VoltageWiring
Factory LineVoltage Wiring
Ground Ground Ground
Junction Box (may be internalor external to the furnace). Theseconnections can be made in thefield supplied disconnect at thefurnace.
Figure 26. Line Voltage Field Wiring
Table 10. Electrical Data
* Time-delay fuses or HACR-type circuit breakers are required.
Furnace Cabinet Nominal Maximum Minimum Maximum Minimum MaximumInput Width Electrical Operating Operating Furnace Wire Fuse or Circuit(Btuh) (in.) Supply Voltage Voltage Amperes Gauge Br eaker Amps*
60,000 19.75 115-60-1 127 103 9.7 14 1580,000 19.75 115-60-1 127 103 9.7 14 15
Thermostat Wire Gauge Recommended Thermostat Wire Length
2-wire (heatin g) 4 or 5-wire (coolin g)
24222018
55 ft.90 ft.
140 ft.225 ft.
25 ft.45 ft.70 ft.
110 ft.
R C
Y G
W
Flame Signal Light (Yellow)
60 90 120
180
TWIN
3 Amp FuseCOM
24 V
HU
M
Neutrals
4 1
5 2
6 3
7
8
9
4
5
6
1
2
3
EA
C
HU
M
M1
M2
M3
CO
OL
HE
AT L1
XF
MR
Unused Motor Leads
EA
C
Electronic Air Tap(.5A@ 120 VAC)
StatusLight (Red)
Humidifier Tap(.5A@ 120 VAC)
ConnectNeutralLead of
ElectronicAir Cleaner
and/or HumidifierHere.
Common Leads
Blower OffTiming
These motor speed taps arenot used for two-stage models
Figure 27. Blower Speed Tap Location
tral line is connected to the white wire and theincoming "hot" line is connected to the blackwire in the furnace junction box. The furnace willnot operate unless polarity and ground areproperly connected. See Figure 26.
! CAUTION:Label all wires prior to disconnectionwhen servicing controls. Wiring errorscan cause improper and dangerousoperation.
Verify proper operation after servicing.
! ATTENTION:Lors des opérations d'entretien descommandes, étiqueter tous les filesavant des les déconnecter. Toute erreurde câblage peut être une source dedanger et de panne.
S'assurer du bon fonctionnement del'appareil après tout entretien.
Low Voltage WiringInstall the thermostat per the manufacturer'sinstructions. The low voltage (24 volt) connec-tions from the thermostat are made at theterminal strip on the control board in the furnace.See Figure 28 for the proper connections forheating only (two-wire) and heating/cooling(four-wire) applications. The recommendedminimum wire gauge for thermostat wiring isshown in Table 10.
26
Figure 28. Low Voltage Field,Four-wire Heating/Cooling Applications
R C
Y G
W
A/C Condensing Unit
Condensing UnitControl Box
RoomThermostat
Flame Signal Light(Yellow)
Status Light(Red)
60 90 120
180Blower Off
Timing
TWIN
3 AmpFuse
COM
24 V
HU
M
Neutrals
Low VoltageConnections
4 15 26 3
7
8
9
4
5
6
1
2
3
EA
C
HU
M M1
M2
M3
CO
OL
HE
AT L1
XF
MR
Unused Motor Leads
EA
C
R Y
G W
Connect R & W
ForHeating
Only
FIELD WIRING
NOTE: The "Y" terminal on the UTEC control board must be connected to the thermostatfor proper coolingmode operation.
The thermostat must not be installed on anoutside wall or any other location where itsoperation may be adversely affected. Adverseaffects include radiant loading from fireplaces,sunlight, or lighting fixtures, and convectiveloading from warm air registers or electricalappliances.
To check the heat anticipator setting either:
1. Add the current draw of the system com-ponents; or
2. Measure the current flow on the thermostatR-W circuit after the circulating blower motorhas started.
Set the heat anticipator according to the ther-mostat manufacturer's instructions for heatanticipator settings.
VENTILATION
Ventilation must be provided for homes built toHUD Manufactured Homes Safety and Con-struction Standards. This ventilation can be sup-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.
For installation of the VentilAire III or IV, followthe instructions provided with the VentilAirekit.
START-UP AND ADJUSTMENTSGeneralPrior to start-up, verify that:
1. The line voltage power leads are securelyconnected, that the polarity of the con-nections is correct, and that the furnaceis properly grounded.
2. The thermostat wires (R, W, Y, and G) aresecurely connected to the correct leadson the terminal strip of the circuit board.
3. The natural gas line service pressure mustnot exceed 10.0 in. water column (0.36psig), and must not be less than 4.5 in.water column (0.16 psig). For LP gas theline service pressure must not exceed 14in. water column (0.51 psig), and must notbe less than 11.0 in. W.C. (0.40 psig).
4. The roll-out and vent safety manual resetswitches are closed. If necessary, pressthe red button to reset a switch. SeeFigure 26 for location. DO NOT install ajumper wire across a switch to defeat itsfunction. If a switch reopens on start-up,DO NOT reset the switch without identify-ing and correcting the fault condition whichcaused the switch to trip.
5. The blower door is in place, closing thedoor switch in the line voltage circuit.
6. The gas line has been purged and allconnections are leak tight.
Start-Up Procedure1. Set the thermostat to the lowest setting.
2. Close the disconnect(s) to provide linevoltage to the furnace.
3. Follow the procedures given on the oper-ating instructions label attached to thefurnace.
4. Set the thermostat above room tempera-ture and verify the sequence of operation.(See the SEQUENCE OF OPERATION.)
27
5. After the furnace has run for approximatelyfive minutes, set the thermostat below roomtemperature and verify steps 9 - 11 of theSEQUENCE OF OPERATION.
Shut Down ProcedureIn the event that the furnace must be shut down,follow this procedure:
1. Set the room thermostat to "OFF" or itslowest temperature setting.
2. Turn OFF the main gas supply to the appli-ance at the manual valve outside of theappliance casing.
3. Remove the control access panel / lou-vered door.
4. Move the appliance gas valve lever/knobto the “OFF” position.
5. Turn OFF the electrical power to theappliance.
Verifying Firing RateThe firing rate must be verified for each instal-lation to prevent over-firing the furnace.
NOTE: The firing rate must not exceed therate shown on the furnace rating plate. Ataltitudes above 4000 ft. it must not exceedthat on the rating plate less 4% for each1000 ft.
Use the following procedure to determine thefiring rate:
1. Shut off all other gas fired appliances.
2. Start the furnace and allow it to run for atleast three minutes.
3. Measure the time (in seconds) required forthe gas meter to complete one revolution.
4. Convert the time per revolution to cubicfeet of gas per hour using Table 11.
5. Multiply the gas flow rate in cubic feet perhour by the heating value of the gas in Btuper cubic foot to obtain the firing rate inBtuh. 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 percubic foot.
• Firing rate = 1000 x 60 = 60,000 Btuh.
6. See the "High Altitude Derate" section foradditional information on firing rate at eleva-tions above 4,000 ft.
The gas valve regulator is set at a nominalvalue of 3.5 in. water column for use with naturalgas. The manifold pressure must be set at 10.0 in.water column for use with LP gas.
Verifying and Adjusting Temperature RiseVerify that the temperature rise through thefurnace is within the range specified on the fur-nace rating plate. Temperature rises outside thespecified range could result in premature heatexchanger failure.
Place thermometers in the return and supplyair stream as close to the furnace as possible.The thermometer on the supply air side mustbe shielded from direct radiation from the heatexchanger to avoid false readings. Adjust allregisters and duct dampers to the desiredposition and run the furnace for fifteen minutesbefore taking any temperature readings. Thetemperature rise is the difference between thesupply and return air temperatures.
For typical duct systems, the temperature risewill fall within the range specified on the ratingplate with the blower speed at the factoryrecommended setting. If the temperature risemeasured is outside the range specified, it maybe necessary to change the blower speed.Lower blower speeds will increase the tem-perature rise and higher blower speeds willdecrease the temperature rise.
The furnace is equipped with a multispeedmotor. Heating and cooling speed selection ismade by moving the leads on the integratedcontrol board located in the furnace. The wiringdiagram on the furnace and Figure 30 show thespeed taps for adjusting motor speed.
If it is desired that the blower operate at the samespeed for heating and cooling, tape off theterminal of the unused blower wire. Install thejumper wire, found in the plastic instruction bag,across the HEAT and COOL taps on the controlboard. Reconnect the desired blower tap to thepiggyback quick connect.
The blower control is designed to start thecirculating air blower 30 seconds after the gasvalve is opened. The blower control is factorywired to turn the blower motor off 120 seconds
28
TIME FOR TIME FORONE REVOLUTION ONE REVOLUTION
(SECONDS) 1 5 10 (SECONDS) 1 5 1024 150 750 1500 80 45 225 45026 138 692 1385 82 44 220 43928 129 643 1286 84 43 214 42930 120 600 1200 86 42 209 41932 113 563 1125 88 41 205 40934 106 529 1059 90 40 200 40036 100 500 1000 92 39 196 39138 95 474 947 94 38 191 38340 90 450 900 96 38 188 37542 86 429 857 98 37 184 36744 82 409 818 100 36 180 36046 78 391 783 102 35 176 35348 75 375 750 104 35 173 34650 72 360 720 106 34 170 34052 69 346 692 108 33 167 33354 67 333 667 110 33 164 32756 64 321 643 112 32 161 32158 62 310 621 114 32 158 31660 60 300 600 116 31 155 31062 58 290 581 118 31 153 30564 56 281 563 120 30 150 300
GAS FLOW RATE (CUBIC FEET PER HOUR)
CUBIC FEET PER REVOLUTION OF METER
CUBIC FEET PER REVOLUTION OF METER
Table 11. Gas Flow Rate
after the gas valve is closed. This timing can bechanged using the BLOWER OFF timing switchopposite the terminal block on the control board(See Figure 27).
Verifying Burner OperationTo verify operation of the burners, remove frontdoor and ensure that the door switch is in the “on”position (see Figure 29). Set the thermostat aboveroom temperature and observe the ignition se-quence. The flame can be observed through thesmall clear window on the burner box. The burnerflame should carry over between all burners. Theflames should be blue, without yellow tips. Flamesshould extend from each burner without lifting,curling, or floating. After verifying ignition, set thethermostat below room temperature and verifythat the burner flame extinguishes completely.Replace the front door.
Verifying Operation of the Supply AirLimit SwitchTo verify operation of the supply air limit switch,make sure that the blower door is in place andthat there is power to the furnace. Completelyblock the return airflow to the furnace by install-ing a close-off plate in place of or upstream ofthe filter(s). Set the thermostat above room
temperature and verify that the Sequence ofOperation is as described in these instructions.The supply air limit switch should function toturn off the gas valve within approximately fiveminutes. The circulating air and combustionblowers should continue to run when the supplyair limit switch opens. Remove the close-offplate immediately after the supply air limit switchopens. If the furnace operates for more than fiveminutes with no return air, set the thermostatbelow room temperature, shut off the power tothe furnace, and replace the supply air limitswitch.
DESCRIPTION OF COMPONENTS
Figure 29 shows the location of each of thefunctional components described below. If anycomponent of the furnace must be replaced,use only factory authorized replacement parts.Contact your distributor for the approved re-placement parts.
Flame Sensor – The flame sensor acts toprove that flame has carried over from theignitor to the opposite end burner. If no flame issensed, the furnace will be shut down automati-cally.
29
Gas Valve – The gas valve controls the flow ofgas to the burners. When the gas valve isenergized it automatically opens and regulatesthe gas pressure in the manifold.
Pressure Switch – The pressure switch veri-fies that the inducer is drawing the combustiongases through the heat exchanger. It also sensesa blocked condensate drain condition.
Deck Limit Switch (Auxiliary Limit) – Thedeck limit protects the furnace filter tempera-ture from overheating when the motor hasmalfunctioned. If the deck switch opens, thepower for the furnace will shut down (seeFigure 29).
Supply Air Limit Switch – The supply air limitswitch prevents the air temperature leaving thefurnace from exceeding the maximum outlet airtemperature.
Vent Safety Switch – The vent safety switchshuts the furnace down if the outlet flue gastemperature increases above 145°F. Thisswitch protects the plastic flue system and theinducer from over-temperature conditions.
Flame Roll-Out Switch – This switch pro-vides flame roll-out protection to the furnaceand combustion air inlet pipe.
MAINTENANCE
It is recommended that the furnace be checkedyearly. At a minimum, this check should includethe following items:
! WARNING:To avoid electric shock, personal injury,or death, turn off the power at thedisconnect or the main service panelbefore performing any maintenance.
! WARNING:Holes in the vent pipe or heat exchangercan cause products of combustion toenter the occupied space. Replace thevent pipe or heat exchanger if leaks arefound. Failure to prevent products ofcombustion from being circulated intothe occupied space can crate poten-tially hazardous conditions, includingcarbon monoxide poisoning, that couldresult in personal injury or death.
Combustion Air and Vent SystemCheck the combustion air and vent pipe toensure that it is not damaged, corroded orblocked by debris. Any damaged section ofvent pipe must be replaced, and any obstruc-tion or blockage must be removed prior tooperating the furnace.
Air Filter
An air filter is supplied with the furnace asshipped from the factory. Filters should bechanged or cleaned monthly during the heatingseason. New or newly renovated homes mayrequire more frequent changing until the con-struction dust has been removed.
Table 12. Accessory Kits
FURNACE ACCESSORY KITSKit Order NumberA/C Coil Box 911969ASide Return Air Kit 904003Top Return Air Kit 904015Sloped Roof VentilAire III Kit 914098Sloped Roof VentilAire IV Kit 914229Soffit VentilAire Kit 917201Concentric Vent Termination Kit (for horizontal and vertical venting)
903578
Horizontal Exterior VentMounting Kit 3"PVC 902375Neutralizer Kit - All Models 902377
30
! WARNING:Never operate the furnace without afilter in place. Dust and lint in the returnair can build up on internal compo-nents, resulting in loss of efficiency,equipment damage, and possible fire.
LubricationThe bearings in the circulating air blower mo-tors are pre-lubricated and sealed at the fac-tory. No further oiling of the bearings is requiredfor the life of the motor.
Condensate Drain AssemblyBe sure the condensate lines are free and open(i.e. avoid kinking hoses). Also make sure allhose clamps are tight to avoid drawing air intothe system.
Blower CompartmentThe blower compartment should be cleanedmonthly during the heating and cooling sea-sons to remove any dirt and lint that may haveaccumulated in the compartment or on theblower and motor. Dirt and lint can createexcessive loads on the motor resulting in higherthan normal operating temperatures and short-ened service life.
Heat Exchanger and Burner MaintenanceThe furnace should operate for many yearswithout excessive soot buildup in the flue pas-sageways, however, the flue passageways,the vent system, and the burners should beinspected and cleaned (if required) by a quali-fied service technician annually to ensure con-tinued safe operation. Particular attention mustbe given to identify deterioration from corrosionor other sources.
SYSTEM OPERATIONINFORMATION
GENERALProper maintenance is most important toachieve the best performance from afurnace. Follow these instructions for yearsof safe, trouble free operation.
• Do not place combustible materials on oragainst the furnace cabinet or the vent pipe.
• Do not store gasoline or any otherflammable vapors and liquids in the vicinityof the furnace.
• Change or replace the air filters monthlyduring any period when the circulatingblower is operating regularly.
• Always replace the doors on the furnaceafter servicing. Do not operate the furnacewithout all doors and covers in place.
• Avoid operating the furnace when windowsand doors are open.
• Be sure that the thermostat is properlyinstalled and is not being affected bydrafts or heat from lamps or otherappliances.
Sequence of OperationOperating sequences for the heating, cooling,and fan modes are described below. Refer tothe wiring diagrams (Figures 30) and the lowvoltage field wiring diagram (Figure 26) formore details.
Heating Mode:1. On a call for heat the thermostat closes,
applying 24 VAC to the W terminal on thecontrol board.
2. The control board checks for continuityon the 24 VAC limit control circuit (over-temperature limit switch, flame rolloutswitches and blocked vent switch in se-ries). If an open limit is detected the con-trol board will energize the inducer andthe conditioned air blower. All other sys-tem functions will be inoperable until thelimit circuit closes. While the limit is open,the red LED will pulse at a rate of 1 blinkper unit time.
3. The furnace control checks for continuityacross the pressure switch (24 VAC). Ifthe pressure switch is closed the heatmode sequence will not continue. If itremains closed for 10 seconds the redLED will blink 3 times repetitively until thefault condition clears.
4. The inducer is energized.5. The pressure switch will close. If the
pressure switch does not close after 10seconds the fault LED will blink 2 timesrepetitively and the inducer will continueto run until the switch is closed.
6. The inducer will pre-purge for 30 secondsand then the igniter will start its warm-upas follows:
31
Initial Power up: After 30 seconds of igniterwarm-up the gas valve (24 VAC) will thenopen. The igniter circuit will stay ener-gized for 3 seconds after the gas valveopens.After Initial Power up: The control has aprogrammed adaptive ignition featurewhich varies the warm-up period as fol-lows: If ignition is successful the warm-up isreduced by 3-seconds on each subsequentcall for heat until ignition failure occurs.Upon ignition failure, the warm-up is in-creased by 3-seconds on the next try. Ifsuccessful, the timing remains fixed at thislevel. In general, whenever ignition failureoccurs the warm-up interval is increased by3-seconds on the next try. And if success-ful, it remains there. Minimum and maxi-mum warm-up time limits are set at 6 and54-seconds, respectively.
7. The furnace control must prove flame viathe flame sensor 5 seconds after the gasvalve opens. If flame is sensed, all burn-ers are on and the ignitor cools off. If noflame is sensed, the gas valve closesimmediately and the inducer continues torun. A second trial for ignition (step 6)begins if no flame is sensed. On the fifthtry for ignition, the furnace control is lockedout and the red LED will blink 4 timesrepetitively. The thermostat must beopened for at least ten seconds to resetthe furnace control after a lock out. Oth-erwise, the furnace will attempt anotherignition sequence in 1 hour.
8. The furnace control energizes the cir-culating air blower on the heating speed30 seconds after the gas valve circuit isenergized .
9. When the thermostat has been satisfied,gas valve is de-energized.
10. The inducer is de-energized after a 30-second postpurge.
11. The furnace control keeps the circulatingair 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 duringoperation, the inducer and circulating airblower continue to operate. The gas valveis de-energized immediately. The blowerscontinue to operate until the limit closes.When the limit closes the inducer blower isde-energized immediately. The circulatingair blower continues to operate for the speci-fied delay (factory set at 120 seconds).
Cooling Mode:1. On a call for cooling the thermostat closes,
applying 24 VAC to the G and Y terminalson the furnace control. This closes thecompressor contactor.
2. The furnace control energizes the circu-lating blower (115 VAC) on the coolingspeed.
3. When the thermostat is satisfied, the Gand Y terminals on the control board arede-energized opening the compressorcontactor.
4. The circulating air blower is de-energizedafter a 90-second delay.
Fan Mode:1. On a call for fan operation, the thermostat
applies 24 VAC to the G terminal on thefurnace control board.
2. The circulating air blower is energizedimmediately on the heating speed.
3. If the furnace is operated in the continu-ous ON position at the thermostat and isthen switched to AUTO, the circulatingblower will operate for a specified delay(factory set at 120 seconds).
Furnace Fails to OperateIf the furnace does not operate check thefollowing: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.)9. Is the deck switch open?
If the furnace locks out after 5 attempts forignition, it will try again every hour if a call forheat remains. If the inducer and circulating airblowers are operating, and items 1 through 8have been checked, press the red reset but-ton on the vent safety switch. (See Figure 29.)If the furnace operates after depressing thereset button, contact a qualified service tech-nician to identify and repair the problem.
If furnace still fails to operate, depress the redreset buttons on the flame roll-out switch. Ifthe furnace operates after depressing thereset button, contact a qualified service tech-nician to identify and repair the problem.
32
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
21
22
M3 Downflow Furnace
1 Door Assembly - Louvered
2 Filter Inside Door
3 Blower Assembly
4 Control Board
5 Pressure Switch
6 Flame Rollout Switch
7 “J” Trap Hard Tube
8 Low Voltage Transformer
9 In Line Drain Assembly
10 Junction Box
11 Vent Safety Switch
Figure 29. Location of Major Components
12 Ignitor Assembly
13 Burner View Port
14 Main Limit Switch
15 Coil Cabinet Assembly (Optional)
16 Flame Sensor (On Burner Box)
17 Gas Valve
18 Switch, On/Off
19 Blower, Inducer
20 Orifice (In Burner Box)
21 Aux. Limit
22 Burner Box
33
Figure 30. Downflow Furnace Wiring Diagram
WD #710240B
If any of th e ori ginalwit h
the furnace must bereplaced, i t must bereplaced wirin gmaterial havin g a
ratin g ofat least ˚ C.
Use co pperconduc torsonly.
IGNITOR
INDUCER
GAS
VALVE
SUPPLY AIRLIMIT SWITCH(ALL MODELS)
VENTSAFETYSWITCH
(ALL MODELS)
TRANSFORMER
FLAME SENSOR
C
GREEN
BLACKWHITE
BLUE
24 V 120 V
OR
AN
GE
BLU
E
BLU
E
YELLOWBROWN
RED
BLACK
WHITE
ORANGE
BLUE
BLA
CK
OR
AN
GE
BLACK
RED
AIR CONDITIONERCONDENSING UNIT
BLACK
BLACKR
WHITE
BLACK
WHITE W/ BLK STRIPES
BLK W/ WHITE STRIPES
WHITE (NEUTRAL)
BLACK 120V
GROUND
ROOM THERMOSTAT
3 OR 4 SPEED MOTOR
H
MHML
L
C
WH
ITE
RE
D
OR
AN
GE
BLU
E
BLA
CK
MOTORPLUG
1
2
3
4
5
6
BLACK
BLUE
FLAME ROLL-OUTSWITCH
(ALL MODELS)
PRESSURESWITCH
R
Y
G
W
C
Y
1801209060
Legend
Field WiringFactory Wiring:
Low VoltageHigh Voltage
BLOWER DECK SWITCH
Factor y WiredHeatin g Speeds
FurnaceInput, Btu h
60,000
80,000
WireColo r
Red
Blue
Power On
Limit Circuit Open or External Load On "W"(Does not apply to Deck Switch, see below)
Pressure Switch Open with Inducer On
Pressure Switch Closed with Inducer On
Ignition Failure (Check Ground)
115 VAC & Neutral Reversed or no Ground
False Flame or Gas Valve Relay Shorted
ON
1 FLASH
2 FLASHES
3 FLASHES
4 FLASHES
5 FLASHES
Continuou s
STATUSRED LIGHTFAULT CONDITION
Power Off or Deck Limit Open
Low Flame Sensor Signal
Flame Present
Continuou sFlash
OFF
ON
FLAMEYELLOW
LIGHTFAULT CONDITION
ON/OFF SWITCH
34
35
UNIT MODEL NUMBER ________________
Minimum Clearances per Table 3? ________
Electrical Connections tight? _____________
Line Voltage Polarity correct? ____________
Supply Voltage: ___________________ Volts
Blower Motor HP: _____________________
FUEL TYPE:
Natural Gas ______ LP/Propane _______
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 forcombustion and ventilation? _____________
Furnace Input: _________________ (Btuh)
Supply Air Temperature: __________ (° F)
Return Air Temperature: _________ (° F)
Temperature Rise: ______________ (° F)
UNIT SERIAL NUMBER ________________
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? __________________
Has the Thermostat been calibrated? _____
Is the Thermostat level? ________________
Is the Heat Anticipator Setting correct? ____
Has the Owner's Information been reviewedwith the home-owner? _________________
Has the Literature Package been left near thefurnace? ____________________________
LOCATION ____________________ CITY __________________ STATE ____________
INSTALLER ___________________ CITY __________________ STATE ____________
INSTALLATION/PERFORMANCE CHECK LIST
O’Fallon, MO
708219D (Replaces 708219C)
Specifications and illustrations subject to change withoutnotice and without incurring obligations. Printed in
U.S.A. (04/04)
¢7082197¤708219D
