Thermo Products CMA1-50N, CMA2-75N User Manual

GAS FIRED HIGH EFFICIENCY FURNACE

DOWN FLOW & DIRECT VENT (SEALED COMBUSTION)

MODEL: CMA1-50N & CMA2-75N
INSTALLATION AND SERVICE MANUAL

For installation in:

1. Manufactured Homes

2. Modular Homes/Buildings

3. Site Constructed—Residential (Single Story Dwellings)

FOR YOUR SAFETY

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.

• 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.

: If the information in these instructions is not followed exactly, a fire or explosion may

result causing property damage, personal injury, or loss of life.

: 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 fuel supplier.

: Do not use this appliance if any part has been underwater. Immediately call a
qualified service technician to inspect the appliance and to replace any part of the electrical or
control system that has been underwater.

PLEASE READ THESE INSTRUCTIONS PRIOR TO INSTALLATION, INITIAL FIRING, AND BEFORE
PERFORMING ANY SERVICE OR MAINTENANCE. THESE INSTRUCTIONS MUST BE LEFT WITH THE USER
AND SHOULD BE RETAINED FOR FUTURE REFERENCE BY QUALIFIED SERVICE PERSONNEL.

THERMO PRODUCTS, LLC.
NORTH JUDSON, IN 46366

PHONE: [phone]
MG-508

ECN 5135-MA 100615

POST OFFICE BOX 217

MADE IN USA

TABLE OF CONTENTS

SECTION BEGINNING PAGE

I. SAFETY INFORMATION 1
II. FURNACE SPECIFICATIONS 6
III. GENERAL INSTRUCTIONS AND CLEARANCES 7
IV. GENERAL INSTALLATION 9

A. FURNACE LOCATION 9
B. BASE INSTALLATION 12
C. ALCOVE INSTALLATION 13
D. CLOSET INSTALLATION 14
E. FUEL PIPING 15
F. GENERAL VENTING REQUIREMENTS 16
G. CONNECTING THE EXHAUST VENT, AND COMBUSTION 18
AIR INTAKE
H. DIRECT VENTING THROUGH A SIDEWALL 19
I. INSTALLATION OF OUTSIDE EXHAUST/INTAKE TERMINATIONS 23
J. CONNECTING THE FURNACE TO ROOF VENT/ INTAKE TERMINATIONS 24
K. CONDENSATE DRAIN LINE AND TRAP ASSEMBLY 26

L. ELECTRICAL WIRING 27

V. STARTING THE UNIT 32

A. SEQUENCE OF OPERATION 32
B. INITIAL START-UP 34
C. ADJUSTMENT OF BTU INPUT RATE 35
D. BURNER ADJUSTMENT 36
E. SETTING TEMPERATURE RISE 37

F. FURNACE CHECK-OUT PROCEDURE 38
VI. INSTALLER'S INSTRUCTIONS TO USER 39
VII. DEALER MAINTENANCE 39

A. ELECTRICAL 40

B. GENERAL INSPECTION 40

C. HEAT EXCHANGER 41

D. HOUSE AIR BLOWER 41

E. RETURN AIR FILTER 41
VIII. TROUBLE SHOOTING 42
APPENDIX-A REPLACEMENT PARTS 49

APPENDIX-B WIRING DIAGRAM 51
WARRANTY 52

REFERENCED PUBLICATIONS: FOR COPIES CONTACT:
NATIONAL FUEL GAS CODE NATIONAL FIRE PROTECTION ASSOCIATION
NFPA 54/ANSI-Z233.1 1 BATTERYMARCH PARK
(LATEST EDITION) P.O. BOX 9101
QUINCY, MA 02269-9101

All installations and services must be performed by qualified service personnel.

I. SAFETY INFORMATION

This and the following page contain reproductions of the various warning and instruction
labels placed on the Thermo Pride Condensing Gas Furnaces. Please read and comply
with the contents of these labels.

1

All installations and services must be performed by qualified service personnel.

This and the previous page contain reproductions of the various safety and instruction
labels placed on the Thermo Pride Condensing Gas Furnaces. Please read and comply
with the contents of these labels.

2

All installations and services must be performed by qualified service personnel.

The following safety information should be read, understood, and followed by the
installer.

1. Use only with type of gas approved for this furnace. Refer to furnace rating plate.

2. Do not install this furnace where it could be exposed to drafts or other wind or
moisture conditions. Refer to Section IV of this manual.

3. Provide adequate ventilation air to the furnace space. Refer to Section IV, C and D,
of this manual.

4. Connect this furnace to an approved vent system only. Combustion products must
be carried outdoors. Refer to Section IV, F thru J, of this manual.

5. Never test for gas leaks with an open flame. Leak test methods must comply with
State, Local and National codes including the National Fuel Gas Code NFPA 54/ANSI­Z233.1 (Latest Edition).

6. Always install furnace with a duct system that has an external static pressure within
the allowable range referenced in specifications.

7. Make sure supply air ducts are completely sealed to the furnace casing. Refer to
Section IV.

The following pages contain various warnings and cautions found throughout the
Thermo Pride Gas Fired High Efficiency Furnace Manual. Please read and comply
with the statements below.

: This furnace is not to be used for temporary heating of buildings or

structures under construction.

: These high efficiency condensing furnaces are not certified for and

shall not be vented into a standard or any type of chimney.

: Negative pressure inside the closet with closet door closed and the

furnace blower operating on high speed shall be no more negative than minus

0.05 inch water column.

: Do not obstruct any return air openings, including the return grille on
the furnace. To do so may cause the furnace to activate the high limit and shut
down.

3

All installations and services must be performed by qualified service personnel.

: The vent and air intake elbows must be kept away from bushes,

shrubs or any vegetation that may restrict the flow of flue products. It must also
be kept clear of any leaves, weeds or other combustible materials. Keep the vent
hood clear of snow. Avoid locating the terminals in areas where standing water or
condensate drippage may be a problem.

: This CMA furnace has been designed to be installed as a direct vent
system and must have its combustion air brought in from outside the conditioned
space. The failure to install the vent/air intake system as specified in these
instructions will void the heat exchanger warranty and may result in property
damage, personal injury or loss of life.

: Outside combustion air must not come from an area that is directly

adjacent to a pool, hot tub or spa. Measures should be taken to prevent the entry
of corrosive chemicals or vapors to the combustion and ventilation air supply.
Such chemicals include but are not limited to chlorinated and/or fluorinated
hydrocarbons such as found in refrigerants, aerosol propellants, dry cleaning
fluids, degreasers and removers. Other harmful compounds may come from
bleaches, air fresheners or mastics. Vapors from such products can form acid
compounds when burned in a gas flame. Should acid compounds form in your
furnace, it may reduce the life of the furnace.

: Because of the potential of odorant fade, a gas leak may not be
detected by smell. If this furnace is installed below grade, contact your gas
supplier for a gas detector.

: All gas piping must be leak tested methods approved by State, Local
and National Codes including the National Fuel Gas Code NFPA 54/ANSI-Z233.1
(Latest Edition). A final test for gas leakage must be made after purging the gas
line. This test must be conducted with the unit operating and should include the
furnace piping and gas valve. Never use an open flame to check for a gas leak.

: Care must be taken not to wet electronic components during leak test.

Wetting the primary ignition module may damage its circuitry and cause a
hazardous situation. Dry moisture from all leads and terminals if wetting occurs.
Wait at least 24 hours for the circuit to fully dry before energizing the burner
circuit.

: The furnace and its individual gas shutoff valve must be disconnected
from the gas supply during pressure testing of the gas supply system at
pressures in excess of 1/2 PSIG or 14.0" w.c. The furnace must be isolated from
the gas supply by closing its manual shut off valve at test pressures equal to or
greater than 1/2 PSIG or 14.0" w.c.

4

All installations and services must be performed by qualified service personnel.

: Copper and brass tubing and fittings (except tin lined) shall not be
used if the gas contains more than a trace (0.3 grains per 100 cubic ft.) of
hydrogen sulfide gas. Check with your gas supplier.

: TURN OFF THE ELECTRICAL POWER to the furnace before attempting
to change blower speed wiring.

: Turn off power to furnace before it is placed into service. The gas
piping system must have been leak tested by a qualified heating contractor in
accordance with State, Local and National Codes including the National Fuel Gas
Code NFPA 54/ANSI-Z233.1 (Latest Edition).

: It may be necessary to purge the air out of the gas line for initial start­up of the furnace after installation. This should be done by a qualified heating
contractor. If excessive gas escapes when purging the gas supply at the union,
allow the area to ventilate for at least 15 minutes before attempting to start the
furnace. LP gas is especially dangerous because the specific gravity of LP gas
allows it to accumulate at floor level at a dangerous concentration.

: Heat exchanger oil will burn off on initial firing creating an unpleasant
odor. To prevent this odor from occurring more than once, it is suggested that:

1. A window(s) be opened.

2. The thermostat set at highest setting.

3. The furnace remain running at conditions 1&2 above for 15 minutes or until
odor has dissipated.

: The CMA furnace models are of direct vent design and do not require

an air shutter adjustment (air shutters are not used) for proper flame
characteristics. Burner box access cover must always be secured with all screws
in place and tightened before operating furnace.

: Personal injury or property damage could result from repair or service
of this furnace by anyone other than a qualified heating contractor.

: Label wires prior to disconnection when servicing controls. Wiring

errors can cause improper and dangerous operation.

: The inducer motor mounting plate gasket and the collector box gasket

must be replaced if they show any sign of having been damaged.

: Power must be disconnected before servicing.

5

All installations and services must be performed by qualified service personnel.

II. FURNACE SPECIFICATIONS - CMA SERIES

MODEL CMA1-50 CMA2-75

INPUT IN BTUH 50,000 75,000
OUTPUT IN BTUH 48,000 72,000
MAIN ORIFICE-NAT.
MAIN ORIFICE-LP

GAS SUPPLY PRESSURE

L.P. MINIMUM
NAT. MINIMUM
L.P. MAXIMUM
NAT. MAXIMUM

GAS MANIFOLD PRESSURE

L.P.
NAT.
INTAKE SIZE IN INCHES
VENT SIZE IN INCHES
NOMINAL TEMPERATURE RISE
SEASONAL EFFICIENCY (AFUE*)

*ANNUAL FUEL UTILIZATION EFFICIENCY

10.0” +

3.5” +

#42

1.5 mm

11” IN.W.C.

4.5”IN.W.C.
14” IN.W.C.
14” IN.W.C.

.03 IN.W.C.

.03 IN. W.C.

2”

2”
55°F
95%

DIMENSIONS

CABINET SIZE
SUPPLY AIR OUTLET

ELECTRICAL SU PP LY
FUSE OR HACR BREAKER
TOTAL CURRENT AMPS
NOMINAL ANTICIPATOR SETTING

FILTER SIZE
APPROXIMATE SHIPPING W EI G HT

BLOWER DATA

BLOWER MODEL
MOTOR HORSEPOWER
MOTOR RPM

CFM @ .2 & .5 IN. W.C. SPEED .2”

LOW 805 695 | 797 668

MD-LOW 1010 860 | 995 869

MD-HIGH 1196 1038 | 1210 1076

HIGH 1338 1162 | 1420 1259

WIDTH 18” DEPTH 25-3/4" HEIGHT 57"

WI DT H 12 ” DEPT H 12"

115 VOLTS-- 60HZ --1/PH

15 AMPS

7.15 AMPS

0.8 MILLIAMPS

(1) 18” X 24” X 1”

175 LBS.

12-9T DIRECT DRIVE

1/2

1065 (HIGH SPEED)

.5” |.2” .5”

FOR BURNER COMBUSTION INFO RMATION REFER TO INITIAL STARTUP.

6

All installations and services must be performed by qualified service personnel.

INSTALLATION PARTS PACKAGE

PARTS PKG#
DESCRIPTION

J-box cover 350020 1 350020 1
wire nut 300132 2 300132 2
3" stainless steel hose clamp 300276 4 300276 4
2-3/8" radiator hose 410017 2 410017 2
CPVC adapter 320833 1 320833 1
LP conversion kit AOPS7677 1 AOPS7678 1

CMA*-50 CMA*-75
S00S4179 S00S4114
PART # QTY PART # QTY

III. GENERAL INSTRUCTIONS AND CLEARANCES – READ BEFORE START OF INSTALLATION

1. The BTU output capacity of the furnace proposed for installation should be based
on a heat loss calculation made according to the manuals provided by the Air
Conditioning Contractors of America (ACCA) or the American Society of Heating,
Refrigeration and Air Conditioning Engineers, Inc. (ASHRAE).

2. This furnace is equipped with orifices sized for operation with natural gas. For
conversion to Propane Gas see instruction MG-799 in Gas Conversion Kit
AOPS7678.

3. These Category Type IV furnaces are shipped completely assembled and wired
(internally). See the Dealer Receiving and Freight Claim Procedure Section of the
price guide for parts shortage or damage. The furnace and duct system must be
adjusted to obtain a temperature rise of 40°F to 70°F through the furnace after
installation. (See rating label located on separator panel inside the furnace
vestibule). The installation must conform with local codes, or in the absence of local
codes, with the National Fuel Gas Codes (ANSI Z223.1 or latest edition) and with
these instructions.

: This furnace is not to be used for temporary heating of buildings or

structures under construction.

Many of the chemicals used during construction, when burned, form acid bearing
condensate that can substantially reduce the life of the heat exchanger.

4. It is recommended that a commercially available CO alarm be installed in
conjunction with any fossil fuel burning appliance. The CO alarm shall be installed
according to the alarm manufacturer’s installation instructions and be listed in

7

All installations and services must be performed by qualified service personnel.

accordance with the latest edition of the UL Standard for Single and Multiple Station
Carbon Monoxide Alarms, UL 2034, or the CSA International Standard, Residential
Carbon Monoxide Alarming Devises, CSA 6.19.

5. The 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. Total

24, Part 280.)

b. American National Standard (ANSI-119.2/NFPA-501C) for all recreational

vehicle installations.

c. American National Standard (ANSI-Z223.1/NFPA-54) for all gas-fired

furnaces.

d. American National Standard (ANSI-C1/NFPA-70 Electric Code for all

electrical field wiring.

e. These gas-fired units have been investigated under standards ANSI Z 21.47

CAN/CGA Z223-2001 Central Furnace test standards.

f. These gas-fired units have been listed by ETL “For installation as central

furnace special type for single story dwelling.”

: The area around the furnace must be kept free and clear of

combustible materials, especially papers and rags.

: This furnace is not to be used as a construction heater.

Listed below are definitions of “ COMBUSTIBLE MATERIAL” and “NON­COMBUSTIBLE MATERIAL.”

COMBUSTIBLE MATERIAL:

Material made of or surfaced with wood, compressed paper, plant fibers, plastics or
other material that will ignite.

NON-COMBUSTIBLE MATERIAL:

Material that will not ignite and burn. Such materials consist entirely of steel, iron, brick,
tile, concrete, slate, glass or a plaster combination thereof.

8

All installations and services must be performed by qualified service personnel.

MODELS CMA
FRONT
BACK
SIDES
VENT CONNECTOR(PVC)
TOP
PLENUM SIDES
TOP AND SIDES OF DUCT
BOTTOM OF DUCT

CLOSET ALCOVE

6”
0”
0”
0”
0”
1”
1”
1”

0”

18”

0”
0”

0”
1”
1”
1”

Table 1

This heating appliance must be installed with clearances not less than the minimums
shown above as well as ample clearance for easy access to the air filter, blower
assembly, burner assembly, controls, and vent connections.

IV. GENERAL INSTALLATION A. FURNACE LOCATION

1. For best performance, locate the furnace so that it is centralized with respect
to the duct system.

2. The furnace installation is only intended for free air return through the furnace
door louvers. DO NOT connect a ducted return air system directly to the furnace.
An improper return air installation may create a hazard and damage equipment,
as well as void all warranties.

3. This furnace may be installed on a combustible floor when utilizing either the
No. 70 counterflow floor base or CE111S / CE211T coil cabinet for below the
floor duct systems, or the cottage base for floor level air distribution. See Figure
1A for description of Combustible Floor Base and Figure 1C for Cottage Base.

This furnace is ETL listed for closet, alcove or free standing applications. All
applications must comply with the requirements of this manual.

9

All installations and services must be performed by qualified service personnel.

Combustible Floor Base
Model: 70-BASE

Figure 1A.

Coil Cabinet
Model: CE113S Note: This cabinet cannot be utilized as a cottage base.

Figure 1B.

10

All installations and services must be performed by qualified service personnel.

Cottage Base
Model: 01COT-BASE

Figure 1C.

NOTE: Serves as a plenum for single story applications with exposed supply air

systems.

11

All installations and services must be performed by qualified service personnel.

B. BASE INSTALLATION

1. Combustible Floor Base Model: 70 BASE

Use the base bottom panel as a template to mark floor opening locations (see
Figure 2). Cut a square opening in the floor for the supply air connector duct. Cut
the opening 1-inch larger than the square template opening. (duct requires 1-inch
clearance to combustible floor).

Figure 2.

Figure 3.

After cutting openings in the floor, place the bottom panel in position. Mark the
square opening location on the distribution duct at the connection point of the

12

All installations and services must be performed by qualified service personnel.

connector duct. Remove the bottom panel. Cut an opening in the distribution duct
slightly larger than the connector duct. (refer to Figure 2 for location of this cut.)
Cut the connector duct to length. Install the connector duct. Bend over each tab.
Insure an airtight seal by using high temperature sealant or tape on the joint.
Reinstall the bottom panel over the connector duct. Put the base top assembly in
place (see Figure-3).

Slit the corners of connector duct down to the top of the base assembly. If metal
projects more than 1-inch above the top of the base assembly, trim the flanges
down to 1-inch. While the top of distribution duct is being pulled up with one
hand, bend down each side of the connector duct tightly to the base assembly
with the other hand. This assures a tight connection between the base assembly
and the connector duct and that the distribution duct will be full size. Use high
temperature tape and/or high temperature silicone caulking on all joints and
seams to minimize air leakage. Secure the base assembly to the floor with two
screws in the front flange.

2. Cottage Base Model: 01COT BASE

The 01COT BASE cottage base (Figure 1C) is required for a freestanding
cottage base installation. The cottage base allows the two sides and rear to have
an 8” x 12” register installed. IMPORTANT: All joints and seams of supply

ducts must be sealed with a sealing method suitable to the application
conditions and temperatures (I.E. High temperature silicone and/or
aluminum tape). Refer to assembly and installation instructions included with
cottage base for additional information.

C. ALCOVE INSTALLATION

In this application, a minimum of 18 inches of clearance
must

be provided to the front of the unit. See Figure 4.

Note – access to diagnostic view port.

Figure 4.

13

All installations and services must be performed by qualified service personnel.

D. CLOSET INSTALLATION

1. The return air opening into the closet
is to have a minimum free area of 250
sq. in. (see Figure 5).

2. The return air opening may be
located in the top, center or (ideally) bottom
of the closet door or side wall.

Figure 5.

: Do not obstruct any return air openings, including the return

grille on the furnace. To do so may cause the furnace to activate the high
limit and shut down.

3. The cross-sectional area of the return system leading into the closet (when
located in the floor or ceiling) shall not be less than 250 square inches.

4. The total free area of openings in the floor or ceiling registers serving the
return duct system must be at least 350 square inches. At least one register must
be located where it is not likely to be covered by carpeting, boxes, furniture or
other objects.

5. Materials located in the return duct system must have a flame spread
classification of 200 or less.

6. Non-combustible pans having one inch upturned flanges are to be located
beneath openings in a floor return duct system.

7. Wiring materials located in the return duct system must conform to articles
300-22 of the National Electrical Code NFPA70 (Latest Edition).

8. Gas piping is not to be located in or through the return duct system .

14

All installations and services must be performed by qualified service personnel.

E. FUEL PIPING

Sizing and installation of fuel lines must be in accordance with Federal, State &
Local regulations. Including the National Fuel Gas Code NFPA 54/ANSI-Z233.1
(Latest Edition).

NOTE: These furnaces are designed to be gas piped through the left side or the
bottom. For service purposes, it is recommended that the gas union be located
inside the furnace when possible.

: Because of the potential of odorant fade, a gas leak may not be

detected by smell. If this furnace is installed below grade, contact your gas
supplier for a gas detector.

A qualified installer or service person must perform all gas piping and testing.
Piping from the natural gas meter to the furnace shall be in accordance with
requirements of the local gas utility. Piping from the LP tank to the furnace must
follow the recommendations of the gas supplier.

A readily accessible manual shut off valve (certified for the applicable gas) with a
non-displaceable rotor member shall be installed within six feet of the gas
equipment it serves.

A union or flanged connection shall be provided directly up stream of the burner
to allow burner removal. Unions must be of a ground joint type or flange-jointed
type using a gasket resistant to the applicable gas. Pipe dope or sealant certified
to be resistant to the action of the applicable gases should be used on all
threaded joints.

A drip leg must be used on both LP and Natural gas installations prior to the
furnace in order to trap oil, condensate and other impurities which might
otherwise lodge in the gas valve or plug the burner orifice.
A drip leg shall be provided at the outlet of the gas meter when there is excessive
condensation between the gas meter and the furnace. Failure to install a drip leg
may void the limited warranty on the furnace.

: All gas pipe connections must be leak tested using methods

approved by State, Local and National Fuel Gas Code NFPA 54/ANSI-Z233.1
(Latest Edition). Any leaks must be repaired immediately after turning off
the gas supply. A final test for gas leakage must be made after purging the
gas line.

: DO NOT wet electronic components during the leak test.

Wetting electronic components may damage circuitry and cause a
hazardous situation. Dry moisture from all leads and terminals if wetting
occurs. Wait at least 24 hours for the circuit to fully dry before energizing
the system.

15