Nordyne M3RL User Manual

Direct Vent (Sealed Combustion) Forced Air Gas Furnaces

Installation Instructions

M3RL Series 90+ Downflow Condensing Furnace

For installation in:

1. Manufactured Homes

2. Park Models and Manufactured Buildings

3. Modular Homes/Buildings

!

W ARNING:

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.

• 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 sup­plier.

BW 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.

– 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.

• Évacuer l’immeuble immédiatement.

• 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.

BWT Models

!

W ARNING:

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.

Improper installation, adjust­ment, 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.

LEAVE THESE INSTRUCTIONS WITH THE HOMEOWNER.

2

TABLE OF CONTENTS

General ...................................................... 4

Unit Dimensions .................................. 4

Shipping Weights................................ 4

Furnace Specification ........................ 4

Air Flow Data ..................................... 4

Owner's Information ................................ 5

Installation Requirements...................... 6

Location.............................................. 7

Clearance ........................................... 7

Circulating Air Supply ............................ 7

Return Air Provisions .............................. 8

Air Distribution Systems ........................ 9

Duct Connector Selection.................... 10

Duct Installation .................................... 10

Venting and Combustion

Air Requirements ........................... 13

Venting Requirements .......................... 14

Vent Table ........................................ 1 5

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

Drainage of Condensate

From Furnace ................................ 19

Gas Supply and Piping ......................... 20

Leak Check....................................... 21

High Altitude Derate ......................... 21

Pressure Switch .............................. 21

Conversion .............................................. 21

Lighting and Adjustment

of the Appliance .............................. 23

Electrical Wiring ...................................... 24

Line Voltage Wiring ........................... 24

Low Voltage Wiring ........................... 26

Ventilation ................................................ 26

Start-up and Adjustment ........................ 26

Start-Up Procedure ........................... 26

Shut Down Procedure ....................... 27

Verifying and Adjusting Firing Rate ... 27

Temperature Rise ............................. 27

Verifying and Adjusting

Verifying Burner Operation .............. 28

Verifying Operation of the

Supply Air Limit Switch ................. 28

Description of Components ................ 29

Furnace Accessories............................. 29

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

Location of Major Components .......... 32

Wiring Diagram ....................................... 33

Installation/Performance

Checklist ......................................... 35

M 3 R L - 060 A - A W

Application

M-Manufactured Home

Furnace Series

Comfort Model

RL - Condensing Downflow

Heating Capacity

Input, BTUH (000’)

Table 1. Model Identification

Return Air Configuration

Blank - Front
T - Top

Door Color

W - White
G - Gray

Cabinet Dimensions

A - 56" x 19-3/4" x 23-3/4”
B - w/Coil Cavity,
76" x 19-3/4" x 23-3/4"

Electrical Code

A - 1PH, 60 Hz, 120 VAC

3

19-7/8

24-5/8

56-1/16

20-9/32

21-17/32

21-29/32

21-15/16

19-3/16

23-7/16

28-15/32

3-17/32

4-11/16

4-11/16

3-17/32

EXHAUST

VENT

17-13/16

COMBUSTION

AIR

INTAKE

21-11/32

7/8 Diameter

1-19/32

1-19/32

EXHAUST
VENT

1-11/16

COMBUSTION

AIR

INTAKE

3-17/32

24-3/4

20-1/16

18-1/2

18-1/2

(W/ Coil Box)

75-1/4

SIDE RETURN

KNOCKOUTS

SIDE RETURN

KNOCKOUTS

1-1/2

21-15/16

1-19/32

Cooling

Coil
Box

(W/O Coil Box)

GENERAL

(

)

21-11/32

COMBUSTION

17-13/16

EXHAUST

AIR

VENT

INTAKE

19-7/8

3-17/32
COMBUSTION

1-11/16
EXHAUST
VENT

AIR

1-1/2

INTAKE

24-5/8

SIDE RETURN

KNOCKOUTS

21-17/32

21-29/32

20-9/32

1-19/32

Top Return Knockouts

7/8 Diameter

23-7/16

3-17/32

4-11/16

56-1/16

28-15/32

Cooling

Coil

(W/O Coil Box)

3-17/32

4-11/16

19-3/16

Box

20-1/16

Figure 1. Furnace Dimensions

12.000

1.000

1.000

18-1/2

SIDE RETURN

KNOCKOUTS

1-19/32

1-19/32

24-3/4

18-1/2

21-15/16

21-15/16

(W/ Coil Box)

75-1/4

21.000

Top View

(AW and BW Models)

Furnace Specifications / Airflow Data

Furnace Furnace Temp. Recommended

Input Output Rise @ A/C

Model No.

Btuh Btuh .3"WC ° F CFM CFM CFM CFM CFM Ton

Top Return Opening

(BWT Models)

Motor HPMotor

Speed

High* 1660 1599 1544 1474 1410 4
Med-High 1512 1467 1416 1363 1304 3

External Static P ressure ( In ches Water Colum n )

Med-Low 1340 1304 1261 1217 1158 2.-1/2

M3 RL-060

M3 RL-080

Note: Data is for Operation with Filter.

60,000 54,000 3 5 - 65 Lo w* * 1176 1142 1 108 1025 966 2

80,000 72,000 35 - 65 Lo w 1176 1142 110 8 1025 966 2

1/2

High* 1660 1599 1544 1474 1410 4
Med-High 1512 1467 1416 1363 1304 3
Med-Low** 1340 1304 1261 1217 1158 2.-1/2

1/2

* Factory Wired Cooling Tap
** Factory Wired Heating Tap

Table 3. Furnace Specifications/Airflow Data

4

0.1 0.2 0.3

Shipping

Weight

Furnace Model

M3RL 060A A W 150
M3RL 060A B W* 170
M3RL 080A A W 155
M3RL 080A B W* 175

* May include suffix - T

Table 2. Shipping Weight

0.4 0.5Furnace

lbs

!

WARNING:

Do not use this appliance if any part
has been submerged under water. Im­mediately call a qualified service tech­nician 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 instruc­tions and warnings in this manual to insure
maximum performance, safety, and operating
efficiency of these appliances. Improper installa­tion 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.

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 instruc­tions. 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 contain­ing 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 tempo­rary heat of buildings or structures under
construction.

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.

These furnaces may be installed in:

1. Manufactured Homes.

2. Park Models and Manufactured buildings

3. Modular Homes/Buildings
The following are safety guidelines with refer-

ences to their specific sections or pages in the
manual.

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 ventila­tion 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 ap­proved vent system only, as specified in
pages 14-19 of these instructions.

OWNER INFORMATION

NORDYNE has been involved in the design of
products for the manufactured home industry
since the first manufactured home or trailer
was built.

NORDYNE originated the sealed combustion
system, which separates the furnace com­bustion system from the living area of the
home, now a standard for the manufactured
home industry.

NORDYNE engineers developed the first cen­tral heating system and the first central air
conditioner for manufactured homes.

NORDYNE is dedicated to bringing to its cus­tomers the finest heating and cooling comfort
possible. NORDYNE constantly seeks to fur­ther 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.

If you wish to cool your home automatically
with a central air conditioning system investi­gate the excellent NORDYNE cooling systems
available from your heating and cooling con­tractor. 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.

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
you are not able to locate a source for NORDYNE
manufactured housing products in your area.

MANUFACTURER WARRANTY, OWNER’S
RESPONSIBILITIES

It is the sole responsibility of the homeowner to
make certain the gas furnace has been correctly
set up and converted to the proper fuel (L.P. gas
or Natural gas) and adjusted to operate prop­erly. All gas furnaces are manufactured for
Natural gas and must be field converted when
using L.P. gas.

A warranty certificate with full details is included
with these instructions. However, NORDYNE
will not be responsible for any costs found nec­essary to correct problems due to improper
setup, improper installation, furnace adjustments,
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.

5. Correcting problems due to improper gas

supply pressure to the furnace.

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.

Carefully review these responsibilities with your
manufactured housing dealer, service company
or gas supplier so there will be no misunder­standing at a later time.

!

CA UTION:

• Never attempt to alter or modify this

furnace or any of its components.

• Never attempt to repair damaged or

inoperable components. Such action
could cause unsafe operation, ex­plosion, fire and/or asphyxiation.

• If a malfunction has occurred, or if

you feel that the furnace is not oper­ating as it should, contact a qualified
service agency or gas utility for as­sistance.

INSTALLATION STANDARDS

Installer shall be familiar with and comply with all
codes and regulations applicable to the installa­tion of these heating appliances and related
equipment. In lieu of local codes, the installation
shall be in accordance with the current provi­sions 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, Commu­nities, 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 in­stallations.

d. American National Standard (ANSI-Z223.1/

NFPA-54) and/or CAN/CGA B149 for all gas­fired furnace models.

e. American National Standard (ANSI-C1/NFPA-

70) and/or CSA 22.1 Canadian Electric Code
Part 1 for all electrical field wiring.

6

CE générateur d'air chaud doit être installé

A

V

conformément aux instructions du fabricant et
aux codes locaux. En l'absence de code local,
respecter la norme ANSI Z223.,1, institulé Na­tional Fuel Gas Code ou les codes d'installation
CAN/GCA-B149.

The National Fuel Gas Code is available by
writing:

bustible material other than wood flooring. The
furnace may be installed on combustible floor­ing when installed on a Nordyne duct connec­tor (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.

American National Standards Institute, Inc.
1430 Broadway
New York, NY 10018

NFPA publications are available by writing:

National Fire Protection Association
Batterymarch Park
Quincy, ME 02269

LOCATION

The furnace must be installed on a level sur­face, and as close to the center of the air
distribution system as possible. See Figure 1
for overall dimensions to determine the re­quired clearances in hallways, doorways,
stairs, etc. to allow the furnace to be moved to
the installation point. The furnace must be in­stalled so that all electrical components are
protected from water.

Minimum clearances to combustible materials
are listed in Table 4. Access for positioning and
servicing must be considered when locating
the unit.

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-

CLOSETALCOVE

LL MOD ELS Inches Inches

Front 1* 1*
Back 0 0
Sides 0 0

ent 0 0
Top 6 6
Duct (Plenum)
w/ Coil Box 0 0
w/o Coil Box 1/4 1/4
(within 3 feet)

*Note: For 1” clearance, use a fully louvered door with at
least 400 square inches of free airflow area.

When installed in a residential garage, the fur­nace 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.

CIRCULATING AIR SUPPLY

!

WARNING:

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
hazardous conditions including carbon
monoxide poisoning that could result in
personal injury or death.

The floor or platform on which the
furnace is mounted must provide sound
physical support of the furnace with no
gaps, cracks, or sagging between the
furnace and the floor or platform.

The circulating air ductwork must not
be connected to any other heat
producing device such as a fireplace
insert, stove, etc.

GENERAL

Plenums and air ducts must be installed in
accordance with the Standard for the Installa­tion of Air Conditioning and Ventilating Systems
(NFPA No. 90A) or the Standard for the Instal­lation of Warm Air Heating and Air Conditioning
Systems (NFPA No. 90B).

Table 4. Minimum Clearances

7

RETURN AIR PROVISIONS

(mm)

U.S.A. home manufacturers shall comply with
all of the following conditions to have accept­able 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 clear­ance between 1” and 6” from furnace, re­quirements are a louvered door with mini­mum of 235 sq. in. free area, with the open­ings in closet door directly inline with the
louvered openings in the furnace door. For
1” clearance from furnace, use a fully lou­vered door with at least 400 sq. in. of free
airflow area.

d. The cross-sectional area of the return duct

system leading into the closet, when located

in the floor or ceiling shall not be less than 235
square inches.

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”

13 1/4"

10 1/4"

T op View

19"

Connector

of Duct

A Single trunk duct

Dual trunk duct

B

w/crossover connector

Transition duct
w/branches

C

Figure 2. Non-Platinum

Supply Duct System

If "X " (Fl o or Cavi ty) is: Model P ar t Num b er:

English Metric

10 1/4" 260 901992 904013
12 1/4" 311 901993 904014

FLOOR CAVITY
(depth equal to "X" in Figure 5 and Table 5)

x

SUPPLY AIR DUCT

Figure 4.

Use Duct Connecto r

Fin ger Tab Screw Down

7/8" 22 901987 904008

2" 51 901988 904009
4 1/4" 108 901989 904010
6 1/4" 150 901990 904011
8 1/4" 210 901991 904012

Table 5. Duct Connectors

Figure 3.

8

FELT-SEAL(

SPACERS

REDUCER

1

)

(1) FINGER TAB DUCT CONNECTOR ONLY
(2) SCREW DOWN DUCT CONNECTOR ONLY

C

Figure 5.

( )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".

SEE

X

TABLE 5

SIDE WALL

ALT. FUEL
LINE HOLES

C

L

FUEL LINE
HOLE

Figure 6. Closet or Alcove

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:

!

CAUTION:

HAZARD OF ASPHYXIATION: Do not
cover or restrict return air opening.

l. Air conditioning systems may require more

duct register and open louver area to ob-

REAR WALL

10"

C

FLOOR
OPENING

L

23 -1/4"

tain necessary airflow. Use NORDYNE’s
certiduct program to determine proper duct
size for A/C.

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
installed kit. Refer to Table 12 for the NORDYNE
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”.

M3 furnaces with model numbers ending in
BWT are factory configured for the return air to
enter the top of the furnace.

9

2-1/4

14-1/2

20

14-1/2

2-3/4

REAR WALL OF CLOSET OR ALCOVE

FLOOR CUT-OUT

FOR DUCT CONNECTIONS

FURNACE OUTLINE

17-29/32

23-1/4

21-3/4

˚

1-1/4

ALT FUEL LINE

ENTRY

24

Figure 7. Cut-Out Locations

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.

Three typical distribution systems are illus­trated 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.

21-7/16

10

12-7/8

14-3/4

15-1/2
FLOOR CUT-OUT

FOR OPTIONAL

COOLING COIL

FOR NON-PLATINUM

SERIES UNITS

3-19/32

1-3/4

VENT

COMBUSTION AIR INTAKE

FUEL LINE ENTRY

2

1-3/4

FURNACE

OUTER DOOR

cavity. To maximize air delivery, re­move reducer “C” (see Figure 5) to
obtain the largest open area that will fit
the duct/floor construction.

DUCT INSTALLATION

Required floor, ceiling, and roof cut-out open­ings must be carefully located to avoid mis­alignment of the furnace (see Figures 6 & 7).
Installation procedures are suggested for typi­cal furnace installations and need not be fol­lowed in the exact listed sequence.

DUCT CONNECTOR SELECTION

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

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 cut­out measuring approximately 14-1/2" by 14­1/2" (± 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

REAR W

ALL

SUPPLY AIR DUCT

FUEL
LINE
HOLES

MOUNTING
PLATE

FLOOR
OPENING

BEND CONNECTOR TABS
UNDER DUCT OPENING

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.

d. Cut out floor opening and one gas line hole.

INSTALLING PLATINUM SERIES 14”
ROUND DUCT CONNECTOR

a. Place duct connector through the floor open-

ing. (See Figure 9).

b. Secure duct connector to floor.

CUT DUCT OPENING (FINGER TABBED
ONLY)

a. Place duct connector through the floor open-

ing with bottom tabs resting on top of the
supply air duct.

b. Center duct connector and push back against

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.

INSTALL FURNACE MOUNTING PLATE

a. Place mounting plate (supplied within duct

connector) at rear of the floor opening (See
Figure 9).

MOUNTING
PLATE

FLOOR
OPENING

INSTALLING SCREW DOWN DUCT CON­NECTOR

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.

d. Screw plenum to duct making sure a seal is

made between the duct and the duct con-

REAR WALL

FUEL
LINE
HOLES

Finger Tabbed

Duct Connectors

SUPPLY AIR DUCT

Figure 8. Mounting Plate

SCREWS

MOUNTING
PLATE

FLOOR
OPENING

FUEL
LINE
HOLES

SUPPLY AIR DUCT

Screw Down

Duct Connectors

Figure 9. Duct Connector

PLENUM

MOUNTING
PLATE

SCREWS

Platinum Series

FUEL

LINE

HOLES

14” SUPPLY
CONNECTION

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.

INSTALLING FINGER TABBED DUCT CON­NECTORS

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. Bend bottom tabs under and up tightly against

the supply air duct (See Figure 10).
NOTE: The duct connector is designed for use

on ducts 12" in width. When using the connec­tor 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

TABS TABS

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.

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).

1. Score and cut the top of the metal duct as
indicated in Step 1 or Step 2. With Step 1
choice, also cut out the metal from the shaded
area “A”.

2. Fold the duct flap “B” up, (See Step 3).

1. INSERT DUCT PLENUM CONNECTOR
INTO DUCT CUT-OUT.

STEP 1.

Fold Back Flap "B"

Cut- Out

Area "A"

Bend Duct Connector Tabs Up

and Over- (along length of duct)

DUCT DUCT

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.

Fold Back Flap"B"

Cut

"B"

"A" "A"

"A" "A"

"B"

Fold Back Flap "B"

Cut- Out
Area"A"

Top of Duct

Lines Duct

Staple Folded Duct

Flap (typ) to side of Duct

Connector

"B"

"B"

Fold Back Flap"B"

12

STEP 3.

Duct

Duct
Flap "B"

Figure 12. Alternate Installation

STEP 4.

Duct

MTG. PLATE TABS

SECURE FURNACE

WITH 2 FASTENERS AT FRONT

CORNER HOLES

SLIDE FURNACE

ALL THE WAY BACK

ONTO MTG. PLATE

NOTE: Additional fasteners may be used at
rear, sides or through door frame, as desired,
to secure furnace to closet or alcove framing.

VENTING AND COMBUSTION AIR
REQUIREMENTS

Knockout Over Holes

S

UPPLY AIR

D

UC

T

Figure 13. “A”, “B”, & Platinum

Cabinet Furnaces

SLIDE FURNACE

ALL THE WAY BACK

ONTO MTG. PLATE

FUEL
LINE
HOLES

MTG. PLATE TABS

SECURE FURNACE

WITH 2 FASTENERS

AT FRONT CORNER HOLES

SUPPLY AIR DUCT

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).

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.

!

CAUTION:

Snow must not be allowed to restrict or
block the combustion air intake or vent
pipes.

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.

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.

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.

!

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.)

d. Secure front with one (1) fastener at each

corner (See Figure 13 or 14).

!

WARNING:

Furnace installation using methods
other than those described in the
following sections must comply with the
National Fuel Gas Code and all
applicable local codes to provide
sufficient combustion air for the furnace.

13

!

CAUTION:

Do not allow debris to fall into the fur­nace. This could cause unsafe opera­tion and voids the furnace warranty.

VENTING REQUIREMENTS

!

WARNING:

FURNACE MUST NOT BE COMMON
VENTED WITH OTHER APPLIANCES.

General

This section specifies installation requirements
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,

piping lengths must conform completely to the
requirements of Table 6.

The furnace must be vented to the outdoors.

!

WARNING:

CARBON MONOXIDE POISONING

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/CGA B149 Installation Codes
and these instructions. Determine

vent and combustion air

HAZARD

that there is no blockage or re­striction, leakage, corrosion and
other deficiencies which could
cause an unsafe condition.

3. So far as is practical, close all
building doors and windows and
all doors between the space in
which the appliance(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
operate continuously.

5. Turn on clothes dryers and any
other appliance not connected to
the venting system. Turn on any
exhaust fans, such as range hoods
and bathroom exhausts, so they
shall operate at maximum speed.
Do not operate a summer exhaust
fan.

6. Close fireplace dampers.

7. Test for spillage from draft hood
equipped appliance at the draft
hood relief opening after 5 minutes
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
venting system must be corrected
in accordance with the

National

Fuel Gas Code, ANSI Z223.1/NFPA

and/or

54

CSA B149.1, Natural Gas

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.

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

MAXIMUM

y

g

y

g

y

APPLICATION

PV C,CPVC or ABS

DIRECT VENT, DUAL

PIPE LENGTH (ft.)*

Inlet/Outlet

SCH. 40 P i p e S ize 3" 3"

Model M3RL 060
Model M3RL 080

50 50
50 50

*NOTES

1. 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% per
1000 ft. of altitude.

6. Only the above pipe materials are approved for use with these
condensing furnaces.

Table 6. Vent Table

VENT TERMINAL

Clearance above grade, veranda, porch,

A =

deck, or balcony
Clearance to window or door that may be

B =

opened

Clearance to perm anent l

C =

Verti c al clearance to ventilat ed soffi t

D =

locat ed above the termi nal wi t hin a
horizont al distance of 2 feet (61 cm) f rom
the cent er l i ne of t he t erm inal
Clearance to unventilat ed soffi t

E =

Clearance to outside corner

F =

Clearance to i ns i de corner

G =

Clearance to each side of center line

H =

extended above meter/re
Clearance to servic e regulator vent out let 3 feet (1. 83 m )

I =

Clearance to nonm ec hani cal air supply inlet

J =

to buildi ng or t he c om bus tion air inlet t o any
other appliance

Clearance to a m ec hani cal air suppl y inl et 6 f eet (1.83 m) 3 feet (91 c m ) abov e i f wi t hin 10 f eet (3 m)

K =

Clearance above paved sidewalk or pav ed

L =

driveway located on public propert y
Clearance under veranda, porc h dec k, or

M =

balcony

1

In accordance with the current CSA B149.1

2

In accordance with the current ANSI Z223.1 / NFPA 54

† 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 the

closed window

ulator as sembl

AIR SUPPLY INLET

Canadian I n stal lations

12 inches (30 c m ) 12 inches (30 c m )

6 inches (15 c m ) f or appli ances ≤ 10,000
Btuh (3 k W), 12 i nc hes (30 cm) for
applianc es > 10,000 Btuh (3 k W) and ≤
100,00 Bt uh (30 k W), 36 i nc hes (91 cm) for
applianc es > 100, 00 Btuh (30 kW)

3 feet (91 cm) withi n a height 15 feet
above the m eter/re

6 inches (15 c m ) f or appli ances ≤ 10,000
Btuh (3 k W), 12 i nc hes (30 cm) for
applianc es > 10,000 Btuh (3 k W) and ≤
100,00 Bt uh (30 k W), 36 i nc hes (91 cm) for
applianc es > 100, 00 Btuh (30 kW)

7 feet (2.13 m) †

12 inches (30 c m ) ‡

Natural Gas and Propane Installation Code

manufacturer’s installation instructions.”

National Fuel Gas Code

AREA WHERE TERMINAL IS NOT PERMITTED

1

**

**

**
**
**

ulator as sembl

US Installations

6 inc hes (15 cm) for appliances ≤ 10,000
Btuh (3 k W), 9 i nc hes (23 cm) for
applianc es > 10, 000 B tuh (3 kW) and ≤
50,000 Bt uh (15 k W), 12 i nc hes (30 cm) for
applianc es > 50, 000 B tuh (15 kW)

6 inc hes (15 cm) for appliances ≤ 10,000
Btuh (3 k W), 9 i nc hes (23 cm) for
applianc es > 10, 000 B tuh (3 kW) and ≤
50,000 Bt uh (15 k W), 12 i nc hes (30 cm) for
applianc es > 50, 000 B tuh (15 kW)

horizontally

2

*
*

*

*

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, the venting system may not be properly
sized. To test the vent system with the remaining
appliances, follow the test outlined below.

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

operation:

Vent Pipe Material

Vent and combustion air pipe and fittings must
be one of the following materials and must
conform to the indicated ANSI/ASTM standards:

Material Standard

Schedule 40 PVC D1785

PVC-DWV D2665

SDR-21 D2241
& SDR-26
ABS-DWV D2661

Schedule 40 ABS F628

Foam/Cellular Core PVC F891
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
per the piping manufacturer's recommendation
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.

Combustion air must not be drawn from
occupied spaces and a corrosive
atmosphere.

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.

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).

These condensing furnaces have been
certified for installation with zero clearance
between vent piping and combustible surfaces.
However, it is good practice to allow space for
convenience in installation and service.

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.

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 Cana­dian Fuel Gas Code takes precedence.

16

Downflow Furnace

Seal/Caulk

Around Pipe

at Building

90˚ Elbow

12"

Min.

Normal Snow Level

Combustion

See Vent T able 4

Straps or Other Suitable
Supports at Minimum of

Coupling

Upward Pitch - 1/4" Per Foot

Wall

First Support Should be as Close to

Outlet Exhaust Vent

Furnace Connection as Possible

Combustion Air

Intake Pipe

Air Intake Pipe

5 ft. Intervals

Furnace

Figure 16. Horizontal Venting

Vent

3 9/16"

Top View

1 7/8"

3 1/2"

6"

Offset with
Vent for Adequate
Dimensional Clearance

Exhaust
Vent
PVC or
ABS pipe

3" x 2"
Reducer

Support System

on Vertical Rise

Below Joints

Combustion Air
Intake Pipe

Vent

Figure 17. Vertical Venting

5. Avoid areas where condensate drainage
may cause problems by dropping on plant­ers or patios, etc. Also ensure that ex­haust gases will not impinge on windows
or building surfaces, which may be com­promised 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 termi­nate above any public walkways.

First support should be as
close to furnace as possible

5'

Vent

Upward Pitch

Combustion Air Intake

Pipe

1/4" per foot

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
through wall which experiences the least
exposure to winter winds.

17

Horizontal Venting

Vent and combustion air intake terminations
must be as shown in Figure 19 unless the
concentric vent termination kit is used.

!

WARNING:

Ensure that the combustion air vent and
the exhaust vent are configured as
shown in Fig. 19. Improper vent
termination can cause recirculation of
the flue gases. This may result in furnace
vibration. In severe cases, the furnace
will cycle, due to the intermittent contact
between the flame and the flame sensor.
If you note these oscillations occurring,
check the vent configuration. Make sure
that the exhaust vent does not have a 90
degree termination.

For horizontal venting, either the Horizontal
Exterior Vent Mounting Kit or the Concentric
Vent Termination Kit may be used (See Table

12).
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 con­sists of two face plates and an insulating gas­ket 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 cou­plings. 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.

When the above kits are not used the following
steps are required:

1. Check the hole size cut through the exte­rior wall. Insure that the hole diameter is
less than the diameter of the couplings to
be used.

2. Extend the vent pipe through the wall
approximately 1" and seal the area be­tween the wall and pipe.

3. Apply couplings to the vent pipe on the
interior and exterior sides of the wall to
insure the pipe can not be pushed or pulled
through the wall.

4. Insure the combustion air inlet pipe has a 90
degree termination elbow, and is pointing
downward as shown in Figures 19 & 20.

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 in­stalled with a shorter vent.

•The inlet for the combustion intake pipe must

be extended at least one foot above the roofline
or snow accumulation level.

•The outlet of the vent must be extended at least

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 re­quirements from the roof and from each other
must be per Figure 20.

Concentric Vent Termination

A concentric vent termination is approved for
use with these furnaces (See Table 12). For
proper installation of the concentric vent termi­nation, follow the installation instructions pro­vided with the kit.

18

Vent Configuration to
Provide 12" Minimum
height above
Snow Level.

Outside
Wall

12" Min.

19" Max.

Support

1/2"
Armaflex
Insulation or
Equivalent
(if required)

12" Above
Normally
Expected
Snow
Level

Exhaust Vent

Option B

Mounting Kit

Faceplate Secured

to Wall with Screws

Combustion

Air Inlet

Exhaust Vent

Option C

7" Min.

12" Min.
36" Max.

12" Min.
36" Max.

12" min.

36" max.

12" Min. to

Normal Snow Level

Exhaust Vent

8" Min.

Exhaust

Inlet

Option A

Grade
Level
or Normal
Snow

Figure 18. Alternate Horizontal

Vent Installation

DRAINAGE OF CONDENSATE
FROM FURNACE

!

WARNING:

The condensate produced by the furnace
must be drained. Do not connect a water
supply to the drainage hose of the
furnace.

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.

Figure 19. Exhaust and Combustion Air

Pipe Clearances

!

CAUTION:

Do not install additional traps in the
condensate drain.

The condensate drain may exit through the left
side panel, the right side panel, or through the
left or right hole on the bottom panel. (See Figure

21). Ensure that the flexible drain hose is not
kinked.

The condensate should drain from the plastic
collector box (location A in Figure 21) as drop­lets 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.

A= 12" Above Roof or

Snow Accumulation Level

Elbow

10" Min.

A

5" Min.

36" Max.

Exhaust

Vent

Note: If terminations meet-

ing these vertical require­ments exceed the maximum

Combustion

Air Intake

1"

height for safe transit, the
vent and combustion air in­takes may be shipped with
the home for assembly on
site. The furnace must be
labeled to notify the installer/
user not to use the furnace

Exhaust

Plumbing Vent
Roof Boot
(Typ. Both Pipes)

until the vent and combus­tion air intake terminations
are installed.

Figure 20. Vertical Vent Termination

19

A

Collector
Box

Burner
Box

A

Clamp

Step 1: Loosen
Step 2: Rotate to drain direction
Step 3: Retighten

“Hard”
J Drain T ube

Floor

Alt. Drain

Alt. Drain

Floor Cavity

Alt. Drain

Figure 21. Furnace with Condensate Drain Trap Assembly

1. Remove the collector box soft tube at
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
header spout is air tight. Air will be drawn into
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 tub­ing are required as NORDYNE cannot be held
responsible for water leakage which occurs
due to loose hose connections or improperly
sealed drain line pipes.

GAS SUPPLY AND PIPING

General

This furnace is equipped for bottom, left, or
right side gas entry. Typical gas service hook­ups 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.

Keep
Downward
Slope

Alt. Drain

readily accessible for service and/or emer­gency 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 instal­lation 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.

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 pres­sure 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 lique­fied petroleum gases.

!

CAUTION:

Do not use matches, lighters, candles,
or other sources of open flame to check
for gas leaks.

All gas piping must be installed in compliance
with local codes and utility regulations. Some
local regulations require the installation of a manual
main shut-off valve and ground joint union exter­nal to the furnace. The shut-off valve should be

20

NOTE: When pressure testing gas supply
lines at pressures greater than 1/2 psig (14 in.
water column), the furnace must be discon­nected from the gas supply piping system to
prevent damage to the gas control valve.

Main
Blower

Control
Board

CONVERSION

This furnace can be converted from the fac­tory-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 fur­nace.

!

WARNING:

Inducer

Burner
Box

Gas
Valve

Floor

Floor Cavity

Alt. Gas
To Gas
Supply

Line Entry

Figure 22. Typical Gas Piping

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.

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 solu­tion or other approved method.

High Altitude Derate

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.

NOTE: The density of air decreases with in­creasing elevation above sea level. This re­duces the quantity of combustion air drawn into
the furnace under normal operation and requires
the unit be derated by using smaller gas orifices
or lower manifold pressure.

DO NOT REMOVE OR DEFACE THE
ORIGINAL RATING PLATE.

!

CAUTION:

The gas supply shall be shut off prior to
disconnecting the electrical power,
before proceeding with the conversion.

To Turn Off Fuel Supply to the Appliance:

1. Set the room thermostat to “OFF” or its
lowest temperature setting.

2. Turn OFF the main gas supply to the appli­ance at the manual valve, outside of the
appliance casing.

3. Remove the control access panel / lou­vered door.

4. Move the appliance gas valve lever/knob to
the “OFF” position.

5. Turn OFF the electrical power to the appli­ance.

CAPACITY OF BL A CK IRON GAS P IPE ( CU. FT. P ER HOUR)

FOR NAT URAL G AS (SPECIFIC GRAVI TY - 0.6 0 )

NOMINAL LENGTH OF PIPE RUN

BLACK IRON (feet)

PIPE DIAMETER

(in.) 1020304050607080

1/2 130 90 75 65 55 50 45 40
3/4 280 190 150 130 115 105 95 90

1 520 350 285 245 215 195 180 170
1 1/4 1050 730 590 500 440 400 370 350
1 1/2 1600 1100 890 760 670 610 560 530

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.

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.)

Table 7. Capacity of Black Iron Gas Pipe

(cu. ft. per hour) for Natural Gas

=

(specific gravity = .60)

21

To Remove the Burner Assembly:

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.

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 fas­teners 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 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. Carefully remove the burner orifices from the
gas manifold, as shown in Figure 25.

!

CAUTION:

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
type 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 manifold
of the unit.

2. Install the appropriate gas burner orifices
into the gas manifold. Remember if in­stalling 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 in­stallation. After reinstalling the cap, you will
be able to read "NAT" for the conversion to
natural gas or "LP for the conversion to LP
gas.

Furnace

Model Number

M3RL -

060A-A/BW 60,000 4 50 57 50 57 51 58 51 58 52 59
080A-A/B W 80,000 5 49 1.15 mm 49 1.15 mm 50 57 50 57 51 58

Furnace Rating

Pl at e Input

(Btuh)

No. of

Burners

Elevation

0 - 2000

Nat LP Nat LP Nat LP Nat LP Nat LP

Elevation

2000-4000

Elevation

4000-6000

Elevation

6000-8000

Elevation

8000-10000

Table 8. Approximate Orifice Size for Natural and LP Gases

22

Reinstalling the Burner Assembly:

1. Reinstall the gas manifold assembly to the
burner box with the four (4) fasteners,
which were removed earlier.

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 burn­ers should be aligned with the center of the
tubes.

3. Reconnect the gas piping to the gas valve.

4. Reconnect the wires to the gas valve termi­nals.

5. Reconnect the rubber pressure tubes to the
gas valve and the burner box. Reinstall the
burner access cover plate.

6. Reconnect the ignitor at the 2 position
plug.

7. Reconnect the flame sensor wire to the
burner box.

Pressure Gauge Installation

Honeywell
V alve

PRESSURE
REGULATOR
CAP

T

A

N

T

N

A

A

N

T

OR

N

A

T

Figure 23. Convertible Pressure

Regulator Cap

P

L

P

OTHER SIDE
OF CAP

M11678

L

NOTE: For natural gas installations, the in­coming 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 pres­sure 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.

LIGHTING AND ADJUSTMENT OF
THE APPLIANCE

1. Turn ON the gas at the manual valve,
outside of the unit.

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.

3. Turn ON the electrical power to the appli­ance.

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.

Figure 24. Burner Inspection

Burner
Box

Burner
Orifices

Inlet
Pressure
Tap

Inlet

Gas
Manifold

On/Off
Lever

Gas
Valve

Flame

Observation

Port

Access

Cover

Plate

Figure 25. Typical Installation For Sealed

Burner Box With Access Cover Plate

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 instruc­tions provided with your unit for the normal
operating sequence.

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. In a properly adjusted burner assem­bly, 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.

NOTE: Until all of the air is bled out of the gas

line, the hot surface ignitor may not ignite the gas.
If the ignition control locks out, turn the thermostat
to its lowest setting and wait one minute then turn
the thermostat to a point above room temperature
and the ignitor will try again to ignite the main
burners. This process may have to be repeated
several times before the burners will ignite. 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.

Manifold Pressure

The gas valve for the M3 furnace series is
equipped with a special conversion pres­sure regulator cap. The pressure regulator
cap is factory set. If the gas valve is con­verted 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.

Type of Fuel Manifold Pressure

In. WC

ELECTRICAL WIRING

General

Electrical connections must be made in accor­dance with all applicable local codes and ordi­nances, and with the current revision of the
National Electric Code (ANSI/NFPA 70).

For Canadian installations electrical connec­tions and grounding must be done in accor­dance 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.

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.

Natural Gas: 3.5
Propane (LP) Gas: 10.0

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.

24

The furnace cabinet must have an uninter­rupted, 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 meth­ods for grounding are electrical wire or conduit
approved for electrical ground service. Do not
use gas piping as an electrical ground.

NOTE: Proper line voltage polarity must be
maintained in order for the control system to
operate correctly. Verify that the incoming neu-

g)

g)

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.

!

CAUTION:

Label all wires prior to disconnection
when servicing controls. Wiring errors
can cause improper and dangerous
operation.

Verify proper operation after servicing.

!

A TTENTION:

Lors des opérations d'entretien des
commandes, étiqueter tous les files
avant des les déconnecter. Toute erreur
de câblage peut être une source de
danger et de panne.

S'assurer du bon fonctionnement de
l'appareil après tout entretien.

Low Voltage Wiring

Install the thermostat per the manufacturer's
instructions. The low voltage (24 volt) connec­tions from the thermostat are made at the
terminal strip on the control board in the furnace.
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.

90

60

120

Status

COOL

EAC

Electronic Air Tap

(.5A@ 120 VAC)

TWIN

XFMR

180

L1

Common

Leads

Connect

Neutral

Lead of

Electronic

Air Cleaner

and/or Humidifier

Here.

R C Y G W

COM

24 V

3

6

9

2

5

8

1

4

7

EAC

Neutrals

HUM

63
52
41

Humidifier Tap

(.5A@ 120 VAC)

3 Amp Fuse

Unused Motor

Leads

M1M2M3

HUM

Blower Off

Timing

Flame Signal

Light (Yellow)

Light (Red)

HEAT

These motor speed taps are

not used for two-stage models

Figure 27. Blower Speed Tap Location

Furnace Cabinet Nominal Maximum Minimum Maximum Minimum Maximum

Input Width Electrical Operating Operating Furnace Wire Fuse or Circuit

(Btuh) (in.) Supply Voltage Voltage Amperes Gauge Breaker Amps*

60,000 19.75 115-60-1 127 103 9.7 14 15
80,000 19.75 115-60-1 127 103 9.7 14 15

Thermostat Wire Gauge

24
22
20
18

Recommended Thermostat Wire Length

2-wire (heatin

55 ft.

90 ft.
140 ft .
225 ft .

4 or 5-wire (coolin

25 ft.
45 ft.
70 ft.

110 ft .

* Time-delay fuses or HACR-type circuit breakers are required.

Table 10. Electrical Data

Field Supplied
Fused Service

White (Neutral)

Green or Bare

Panel

Black (Hot)

(Ground)

Ground

Field Supplied Disconnect
Within Sight of Furnace

Field Supplied

Panel Connector

Black
White

Ground

Black

White

Field Line Voltage

Black
White

Ground

Junction Box (may be internal
or external to the furnace). These
connections can be made in the
field supplied disconnect at the
furnace.

Wiring
Factory Line

Voltage Wiring

Figure 26. Line Voltage Field Wiring

25

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.

To check the heat anticipator setting either:

1. Add the current draw of the system com­ponents; or

2. Measure the current flow on the thermostat
R-W circuit after the circulating blower motor
has started.

Set the heat anticipator according to the ther­mostat manufacturer's instructions for heat
anticipator settings.

VENTILATION

A/C Condensing Unit

Condensing Unit

Control Box

R Y G W

Connect

R & W

For

Heating

Only

Room

Thermostat

NOTE: The "Y"
terminal on the
UTEC control board
must be connected
to the thermostat
for proper cooling
mode operation.

FIELD WIRING

Low Voltage
Connections

R C Y G W

COM

3 Amp

24 V

3

6

9

2

5

8

1

4

7

EAC

HUM

Neutrals

Unused Motor Leads

HUM

63
52
41

Blower Off

Fuse

Flame Signal Light

Status Light

COOL

M1M2M3

Timing

(Yellow)

(Red)

HEAT

EAC

6090120

TWIN

XFMR

L1

Figure 28. Low Voltage Field,

Four-wire Heating/Cooling Applications

180

Ventilation must be provided for homes built to
HUD Manufactured Homes Safety and Con­struction Standards. This ventilation can be sup­plied by the VentilAire III or VentilAire IV acces­sories. (See Table 12). Alternate means to pro­vide the ventilation air must meet the require­ments of all applicable local and federal codes.

For installation of the VentilAire III or IV, follow
the instructions provided with the VentilAire
kit.

START-UP AND ADJUSTMENTS

General

Prior to start-up, verify that:

1. The line voltage power leads are securely
connected, that the polarity of the con­nections is correct, and that the furnace
is properly grounded.

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. 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. 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 identify­ing and correcting the fault condition which
caused the switch to trip.

5. The blower door is in place, closing the
door switch in the line voltage circuit.

6. The gas line has been purged and all
connections are leak tight.

Start-Up Procedure

1. Set the thermostat to the lowest setting.

2. Close the disconnect(s) to provide line
voltage to the furnace.

3. Follow the procedures given on the oper­ating instructions label attached to the
furnace.

4. Set the thermostat above room tempera­ture 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.

Shut Down Procedure

In the event that the furnace must be shut down,
follow this procedure:

6. See the "High Altitude Derate" section for
additional information on firing rate at eleva­tions 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. The manifold pressure must be set at 10.0 in.
water column for use with LP gas.

1. Set the room thermostat to "OFF" or its
lowest temperature setting.

2. Turn OFF the main gas supply to the appli­ance at the manual valve outside of the
appliance casing.

3. Remove the control access panel / lou­vered door.

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 instal­lation 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.

Use the following procedure to determine the
firing rate:

1. Shut off all other gas fired appliances.

Verifying and Adjusting Temperature Rise

Verify that the temperature rise through the
furnace is within the range specified on the fur­nace rating plate. Temperature rises outside the
specified range could result in premature heat
exchanger failure.

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.

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 tem­perature rise and higher blower speeds will
decrease the temperature rise.

2. Start the furnace and allow it to run for at
least three minutes.

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.

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.

• Firing rate = 1000 x 60 = 60,000 Btuh.

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.

If it is desired that the blower operate at the same
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.

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

27

GAS F L O W RAT E (CUBIC FEET PER HOUR)

TIME FOR TIME FOR

ONE REVOLUTION ONE REVOLUTION

(SECONDS) 1 5 10 (SECONDS) 1 5 10

24 150 750 1500 80 45 225 450
26 138 692 1385 82 44 220 439
28 129 643 1286 84 43 214 429
30 120 600 1200 86 42 209 419
32 113 563 1125 88 41 205 409
34 106 529 1059 90 40 200 400
36 100 500 1000 92 39 196 391
38 95 474 947 94 38 191 383
40 90 450 900 96 38 188 375
42 86 429 857 98 37 184 367
44 82 409 818 100 36 180 360
46 78 391 783 102 35 176 353
48 75 375 750 104 35 173 346
50 72 360 720 106 34 170 340
52 69 346 692 108 33 167 333
54 67 333 667 110 33 164 327
56 64 321 643 112 32 161 321
58 62 310 621 114 32 158 316
60 60 300 600 116 31 155 310
62 58 290 581 118 31 153 305
64 56 281 563 120 30 150 300

CUBIC FEET PER REVOLUTIO N OF

METER

CUBIC FEET PER REVOLUTIO N OF

METER

Table 11. Gas Flow Rate

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).

Verifying Burner Operation

To verify operation of the burners, remove front
door and ensure that the door switch is in the “on”
position (see Figure 29). Set the thermostat above
room temperature and observe the ignition se­quence. The flame can be observed through the
small clear window on the burner box. The burner
flame should carry over between all burners. The
flames should be blue, without yellow tips. Flames
should extend from each burner without lifting,
curling, or floating. After verifying ignition, set the
thermostat below room temperature and verify
that the burner flame extinguishes completely.
Replace the front door.

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 install­ing a close-off plate in place of or upstream of
the filter(s). Set the thermostat above room

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
plate immediately after the supply air limit switch
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.

DESCRIPTION OF COMPONENTS

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 re­placement parts.

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 automati­cally.

28

FURNACE ACCESSORY KITS

(

g)

MAINTENANCE

Kit Order Nu mber

A/ C Coil B ox 911969A
Side Ret urn A i r Kit 904003
Top Return Air K i t 904015
Sloped Roof VentilAire II I Kit 914098
Sloped Roof VentilAire IV K i t 914229
Sof fit V entilAi re K i t 917201
Concentri c Vent T erm ination Kit

for horiz ont al and vertic al ventin
Horizont al E xterior V ent
Mounting Kit 3"PVC 902375
Neutralizer Kit - A l l M odel s 902377

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.

Pressure Switch – The pressure switch veri­fies that the inducer is drawing the combustion
gases through the heat exchanger. It also senses
a blocked condensate drain condition.

Deck Limit Switch (Auxiliary Limit) – The
deck limit protects the furnace filter tempera­ture from overheating when the motor has
malfunctioned. If the deck switch opens, the
power for the furnace will shut down (see
Figure 29).

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.

Flame Roll-Out Switch – This switch pro­vides flame roll-out protection to the furnace
and combustion air inlet pipe.

903578

It is recommended that the furnace be checked
yearly. At a minimum, this check should include
the following items:

!

W ARNING:

To avoid electric shock, personal injury,
or death, turn off the power at the
disconnect or the main service panel
before performing any maintenance.

!

WARNING:

Holes in the vent pipe or heat exchanger
can cause products of combustion to
enter the occupied space. Replace the
vent pipe or heat exchanger if leaks are
found. Failure to prevent products of
combustion from being circulated into
the occupied space can crate poten­tially hazardous conditions, including
carbon monoxide poisoning, that could
result in personal injury or death.

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 obstruc­tion or blockage must be removed prior to
operating the furnace.

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 con­struction dust has been removed.

29

!

WARNING:

Never operate the furnace without a
filter in place. Dust and lint in the return
air can build up on internal compo­nents, resulting in loss of efficiency,
equipment damage, and possible fire.

Lubrication

The bearings in the circulating air blower mo­tors are pre-lubricated and sealed at the fac­tory. No further oiling of the bearings is required
for the life of the motor.

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.

Blower Compartment

The blower compartment should be cleaned
monthly during the heating and cooling sea­sons 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 short­ened service life.

Heat Exchanger and Burner Maintenance

The furnace should operate for many years
without excessive soot buildup in the flue pas­sageways, however, the flue passageways,
the vent system, and the burners should be
inspected and cleaned (if required) by a quali­fied service technician annually to ensure con­tinued safe operation. Particular attention must
be given to identify deterioration from corrosion
or other sources.

SYSTEM OPERATION
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.

• Do not place combustible materials on or
against the furnace cabinet or the vent pipe.

30

• Do not store gasoline or any other
flammable vapors and liquids in the vicinity
of the furnace.

• 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.

• Avoid operating the furnace when windows
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.

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.

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 (over­temperature limit switch, flame rollout
switches and blocked vent switch in se­ries). If an open limit is detected the con­trol board will energize the inducer and
the conditioned air blower. All other sys­tem 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.

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:

Initial Power up: After 30 seconds of igniter
warm-up the gas valve (24 VAC) will then
open. The igniter circuit will stay ener­gized for 3 seconds after the gas valve
opens.
After Initial Power up: The control has a
programmed adaptive ignition feature
which varies the warm-up period as fol­lows: If ignition is successful the warm-up is
reduced by 3-seconds on each subsequent
call for heat until ignition failure occurs.
Upon ignition failure, the warm-up is in­creased by 3-seconds on the next try. If
successful, the timing remains fixed at this
level. In general, whenever ignition failure
occurs the warm-up interval is increased by
3-seconds on the next try. And if success­ful, it remains there. Minimum and maxi­mum warm-up time limits are set at 6 and
54-seconds, respectively.

7. The furnace control must prove flame via
the flame sensor 5 seconds after the gas
valve opens. If flame is sensed, all burn­ers 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
try for ignition, the furnace control is locked
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. Oth­erwise, the furnace will attempt another
ignition sequence in 1 hour.

8. The furnace control energizes the cir­culating 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.

10. The inducer is de-energized after a 30­second 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
air blower continues to operate for the speci­fied 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 terminals
on the furnace control. This closes the
compressor contactor.

2. The furnace control energizes the circu­lating 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 continu­ous 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).

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.)

9. Is the deck switch open?

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 but­ton on the vent safety switch. (See Figure 29.)
If the furnace operates after depressing the
reset button, contact a qualified service tech­nician 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 tech­nician to identify and repair the problem.

31

M3 Downflow Furnace

3

21

2

18

4

5
19

6

22

7

17

1

8

9

10

11

16

12

13

14

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

32

15

12 Ignitor Assembly
1 3 Burner View Port
14 Main Limit Switch
1 5 Coil Cabinet Assembly (Optional)
1 6 Flame Sensor (On Burner Box)
1 7 Gas Valve
18 Switch, On/Off
19 Blower, Inducer
20 Orifice (In Burner Box)
21 Aux. Limit
22 Burner Box

y

o

l

h

ace

be

be

g

g

a

g

of

atleas

C.

r

ductors

y.

SUPPLY AIR

ORPLUG

d

ace

h

0

0

e

r

ed

ue

SH

S

S

S

S

s

US

GHT

s

GHT

LIMIT SWITCH

(ALL MODELS)

WHITE (NEUTRAL)

BLACK 120V

GROUND

ROOM THERMOSTAT

R
Y
G

W

AIR CONDITIONER
CONDENSING UNIT

C
Y

BLUE

FLAME ROLL-OUT

SWITCH

(ALL MODELS)

BLUE

BLUE

BLUE

ORANGE

ORANGE

VENT
SAFETY
SWITCH

(ALL MODELS)

WHITE

GREEN

WHITE W/ BLK STRIPES

BLK W/ WHITE STRIPES

BLACK

TRANSFORMER

24 V

90

60

PRESSURE

SWITCH

ON/OFF SWITCH

WHITE

120 V

BLACK

180

120

BLACK

BLOWER DECK SWITCH

FLAME SENSOR

GAS

VALVE

RED

YELLOW
BROWN

IGNITOR

Legend

Field Wiring

Factory Wiring:

Low Voltage
High Voltage

FAULT CONDITION
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
Power Off or Deck Limit Open

FAULT CONDITION
Low Flame Sensor Signal

Flame Present

R

INDUCER

2 FLASHE

4 FLASHE

C

TAT

RED

LI

ON

1 FLA

FLASHE

FLASHE

ontinuou

OFF

YELLOW

LI

ontinuou

Flash

ON

BLACK

BLACK
BLACK

BLACK

an

thefurn
replaced, itmust
replaced wirin
materialhavin

t

se coppe

n

nl

ftheorigina

wit

must

ratin

RED
ORANGE
BLUE

BLACK

1
2
3
4

MOT

Factory Wire

Heating Speeds

Furn

Input, Btu

60,00

80,00

3 OR 4 SPEED MOTOR

C

L

WHITE

RED

Wir

R

Bl

MH

ML

ORANGE

olo

H

BLUE

BLACK

WD #710240B

Figure 30. Downflow Furnace Wiring Diagram

33

34

INSTALLATION/PERFORMANCE CHECK LIST

LOCATION ____________________ CITY __________________ STATE ____________
INSTALLER ___________________ CITY __________________ STATE ____________

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 for
combustion and ventilation? _____________

Furnace Input: _________________ (Btuh)
Supply Air Temperature: __________ (° F)
Return Air Temperature: _________ (° 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 reviewed
with the home-owner? _________________

Has the Literature Package been left near the
furnace? ____________________________

Temperature Rise: ______________ (° F)

35

O’Fallon, MO

¢7082197¤

708219E

708219E (Replaces 708219D)

Specifications and illustrations subject to change without

notice and without incurring obligations. Printed in

U.S.A. (08/06)