INTERTHERM M3RL High Efficiency Direct Vent Condensing Downflow Gas Furnace Owner’s Manual

: June 15, 2024
: Intertherm

Table of Contents

M3RL High Efficiency Direct Vent Condensing Downflow Gas Furnace
Product Information
Product Usage Instructions
Installation
Maintenance
Troubleshooting
- Specifications
- FAQ
Q: Can this furnace be used with LP (propane) gas?
Q: What is the warranty period for this furnace?
Q: Can I install this furnace myself?

M3RL High Efficiency Direct Vent Condensing Downflow Gas Furnace

Product Information

The high efficiency downflow gas furnace is specifically
designed for Modular Housing. It can be installed in a utility room
or enclosed in a closet. It is CSA design certified for use in the
United States and Canada. All units and components are tested on
the manufacturing line. The furnace features in-shot burners, an
inducer, and insulation, which result in a warm outlet air
temperature at furnace start-up. It has adjustable blower off
settings (60, 90, 120, and 180 seconds) to increase the life of the
heat exchanger. The furnace also utilizes an appliance type ignitor
with a 20-year history of reliability.

The heat exchanger is made of heavy gauge aluminized steel,
ensuring a long life. When matched with a NORDYNE coil, it
increases cooling performance. The furnace can be vertically or
horizontally vented using a two-pipe system for maximum flexibility
in installation. It is designed to provide a wide range of cooling
capacities and includes a 40VA transformer. The burner orifice and
gas valve regulator can be easily changed for convertibility and
troubleshooting.

The furnace is equipped with a transformer and control board
protection, as well as easy field wiring. The door is securely
fastened for transit but allows easy removal for access. It has a
baked enamel finish that protects against rust and corrosion and
allows for easy cleaning. The insulation ensures minimized heat
loss and quiet operation.

Product Usage Instructions

Installation

1. Choose a suitable location for the furnace, such as a utility
room or closet.

2. Ensure proper ventilation for vertical or horizontal
venting.

3. Connect the furnace to the gas supply using the appropriate
fuel line holes.

4. Install the furnace using the provided marks for drilling
location and knockout holes.

5. Secure the door firmly for transit, but leave it easily
removable for access.

6. Connect the furnace to the electrical supply using the
junction box.

Maintenance

1. Regularly clean the furnace’s baked enamel finish to prevent
rust and corrosion.

2. Inspect and replace the air filter as needed to ensure proper
airflow.

3. Check and clean the burner view port for any blockages or
debris.

4. Inspect and clean the blower assembly to maintain its
efficiency.

5. Test the pressure switch and flame rollout switch for proper
functioning.

Troubleshooting

If you encounter any issues with the furnace, refer to the
troubleshooting section in the user manual. It provides
step-by-step instructions for diagnosing and resolving common
problems.

Specifications

Input-Btuh (a): 60,000 or 80,000
Heating Capacity – Btuh: 54,000 or 72,000
AFUE: 90.0
Blower D x W: 10 x 10
Fuse or Breakage Size: 15 Amps
Heat Anticipator Setting: 0.5
Manifold Pressure:
- Natural Gas: 3.5 WC
- LP Gas: 10 WC
Motor H.P. -Speed -Type: 1/2 – 4 – PSC
Motor FLA: 7.9
Maximum Ext. SP – In. W.C.: 0.5

FAQ

Q: Can this furnace be used with LP (propane) gas?

A: Yes, all models can be converted to use LP (propane) gas.

Q: What is the warranty period for this furnace?

A: Please refer to the warranty information provided by the
manufacturer for details on the warranty period.

Q: Can I install this furnace myself?

A: It is recommended to hire a professional HVAC technician for
the installation of the furnace to ensure proper and safe
installation.

The high efficiency downflow gas furnace is especially designed for Modular Housing. It may be installed in a utility room, or enclosed in a closet. CSA design certified for use in the United States and Canada.

All units and each component

(both mechanical and electrical) are tested on the

manufacturing line.

Due to the unique design of

in-shot burners, location of inducer and use of insulation.

At burner start-up

assures a warm outlet air temperature at furnace start-up.

Adjustable blower off settings (60, 90, 120 and 180

seconds).

Increases life of heat

exchanger.

Innovative application

of an appliance type ignitor with a 20-year history of

reliability.

Heavy gauge

aluminized steel heat exchanger assures a long life.

Assures a

long life.

Increases

cooling performance when matched with a NORDYNE

coil.

May be vertically or

horizontally vented using a two-pipe system for maximum

flexibility in installation.

Designed to give a wide

range of cooling capacities. 40VA transformer included.

Simple burner orifice and gas valve

regulator change for ease of convertibility.

for easy troubleshooting.

Protects transformer and control board.

For easy field wiring.

Secures the door firmly for transit,

yet allows easy removal for access.

Protects against rust and other

corrosion. Baked enamel finish allows for easy cleaning.

Insures minimized heat loss

and quiet operation.

BW Models

BWT Models

Note: The M3RL will fit in the same footprint and uses the same duct connector as the M1 funaces. The design of the M3RL allows for direct substitution in place of the M1 series furnaces.

1.000

12.000

MARKS FOR DRILLING LOCATION (2)

21.000 KNOCKOUTS (4)

12.000

5.550

4.466

ALT. FUEL LINE HOLES

SIDE WALL

CL
FUEL LINE HOLE

REAR WALL
10″ FLOOR CL OPENING 23 -1/4″

18-1/2

18-1/2 12.00

4.466

24 x 16 FILTER

9.830

SIDE FILTER BRACKET

MARKS FOR DRILLING LOCATION (2)

TOP FILTER BRACKET

1.000

12.000

21.000

1.000

2

1 Door Assembly – Louvered (AW & BW Models)

Door Assembly – Non Louvered (BWT Models)

2 Filter Inside Door (AW & BW Models)

3 Blower Assembly

2

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

12 Ignitor Assembly

13 Burner View Port

14 Main Limit Switch

15 Coil Cabinet Assembly

(BW & BWT Models)

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

3 21 18 4 5 19 6 22 7
17
1

8
9 10 11 16
12 13
14
15

Input-Btuh (a)

60,000

80,000

Heating Capacity – Btuh

54,000

72,000

AFUE

90.0

Blower D x W

10 x 10

Fuse or Breakage Size

15 Amps 15 Amps

Heat Anticipator Setting

0.5

Manifold Pressure

Nat. Gas

3.5″ WC 3.5″ WC

LP Gas

10″ WC 10″ WC

Motor H.P. -Speed -Type

1/2 – 4 -PSC 1/2 – 4 -PSC

Motor FLA

7.9

Maximum Ext. SP – In. W.C.

0.5

Temperature Rise Range – °F 35 – 65

35 – 65

Direct vent; draft inducer; pressure switch; redundant main gas control; hot- surface ignition; timed ON/OFF blower controls (TDR); 40VA transformer for air conditioner application; limit controls; direct drive motor; all models can be converted to use LP (propane) gas.

M3RL 060A AW M3RL 060A BW M3RL 080A AW M3RL 080A BW
*May include suffix – T

150 170 155 175

Note: All models are 115V, 60 Hz. Gas Connections are 1/2″ N.P.T. AFUE = Annual Fuel Utilization Efficiency (a) Ratings to 4,000 ft. Over 4,000 ft. reduce 4% for each 1,000 ft. above sea level.

21-11/32 COMBUSTION AIR INTAKE
17-13/16 EXHAUST VENT
SIDE RETURN KNOCKOUTS

19-7/8

1-1/2 3-17/32 COMBUSTION AIR INTAKE 1-11/16
EXHAUST VENT
18-1/2

24-5/8
SIDE RETURN KNOCKOUTS

21-17/32 21-29/32
20-9/32 1-19/32

7/8 Diameter
28-15/32 23-7/16 3-17/32 4-11/16

56-1/16 (W/O Coil Box)
3-17/32 4-11/16

18-1/2

(W/ Coil Box) 75-1/4

2211-1-155/1/166 11-1-199/3/322

Cooling Coil Box

19-3/16

20-1/16

24-3/4

ALL MODELS
Front Back Sides Vent Top Duct (Plenum) w/ Coil Box w/o Coil Box (within 3 feet)

CLOSET
Inches
1* 0 0 0 6
0 1/4

ALCOVE
Inches
1* 0 0 0 6
0 1/4

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

M3RL-060 60,000 54,000 35 – 65

M3RL-080 80,000 72,000
Note: Data is for Operation with Filter. * Factory Wired Cooling Tap ** Factory Wired Heating Tap

35 – 65

High* Med-High Med-Low 1/2 Low* High Med-High Med-Low** 1/2 Low

1660 1512 1340 1176 1660 1512 1340 1176

1599 1467 1304 1142 1599 1467 1304 1142

1544 1416 1261 1108 1544 1416 1261 1108

4

1474 1363 1217 1025 1474 1363 1217 1025

1410 1304 1158 966 1410 1304 1158 966

4 3 2.-1/2 2 4 3 2.-1/2 2

Automatic Cavity Damper

“VEE” Box Adapters (10″) – 5 / carton Duct Connector 10″ x 6″ – 6 / carton

“VEE” Box Adapters (12″) – 5 / carton

Single Wide Fitting Kit (12″)

Double Wide Fitting Kit (12″) Single Wide Fitting Kit (14″)

Double Wide Fitting Kit (14″)

Y-Fitting (12″)

Y-Fitting (14″)

A/C Coil Box Side Return Air Kit

Top Return Air Kit

Sloped Roof VentilAire III Kit

Sloped Roof VentilAire IV Kit Soffit VentilAire Kit

Concentric Vent Termination Kit (for horizontal and vertical venting)

Horizontal Exterior Vent

Mounting Kit

3″PVC

Neutralizer Kit – All Models

901083 901985 902926 902149 911468A 911469A 914957 914956 911470 917195 911969A 904003 904015 914098 914229 917201
904176
902375 902377

Soffit Air Inlet (for VentilAire III only) Air Tube Kit M (high capacity M Series gas/oil furnaces) VentilAire III – Sloped 3/12 VentilAire IV – Sloped 3/12

917201 914118 914098 914229

11.25 x 13.50 x 0.88 11.25 x 13.50 x 2.00 11.25 x 13.50 x 4.25 11.25 x 13.50 x 6.25 11.25 x 13.50 x 8.25 11.25 x 13.50 x 10.25 11.25 x 13.50 x 12.25 11.25 x 13.50 x 6.25

12 / carton 12 / carton
6 / carton 6 / carton 4 / carton 3 / carton 3 / carton 24 / carton

901987A 901988A 901989A 901990A 901991A 901992A 901993A 902681A

M-Modular Home

RL – Condensing Downflow

Input, BTUH (000′)

Blank – Front T – Top W – White
A – 56″ x 19-3/4″ x 23-3/4″ B – w/Coil Cavity,
76″ x 19-3/4″ x 23-3/4″
A – 1PH, 60 Hz, 120 VAC

All models are approved for both vertical and horizontal direct (2 pipe) venting applications. See Vent Table below for specified sizes and allowable lengths.

Model M3RL 060 Model M3RC 080

50

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 4,000 ft.

For higher elevations decreasevent pipe lengths by 8% per 1000 ft. of altitude.

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

7

NORDYNE will furnish a replacement for any part of this product which fails in normal use and service within the first year of installation, in accordance with the terms of the warranty.

For complete details of the Limited Warranty, including applicable terms and conditions, see your local installer or contact the NORDYNE warranty department for a copy.

8000 Phoenix Parkway | O’Fallon, MO 63368-3827

Specifications and illustrations subject to change without notice and without incurring obligations. Printed in U.S.A (11/2009)

(Replaces 307B-1008)

www.intertherm.net

Powered by TCPDF (www.tcpdf.org)