Thermo Pride CMA3-50D36N Manual

THERMO PRODUCTS, LLC.
POST OFFICE BOX 217
NORTH JUDSON, IN 46366
PHONE: [phone]
MG-517
ECN 5396-MA 141211 MADE IN USA
GAS FIRED HIGH EFFICIENCY FURNACE
DOWNFLOW & DIRECT VENT (SEALED COMBUSTION)
MODELS:
CMA3-50D36N, CMA3-75D36N,
CMC1-50D36N, CMC1-75D36N,
CMC1-50DV3N, CMC1-75DV3N
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.

TABLE OF CONTENTS
SECTION BEGINNING PAGE
I. SAFETY INFORMATION 1
II. FURNACE SPECIFICATIONS 7
III. GENERAL INSTRUCTIONS AND CLEARANCES 11
IV. GENERAL INSTALLATION 13
A. FURNACE LOCATION 13
B. BASE INSTALLATION 15
C. ALCOVE INSTALLATION 16
D. CLOSET INSTALLATION 14
E. FUEL PIPING 19
F. GENERAL VENTING REQUIREMENTS 20
G. CONNECTING THE EXHAUST VENT, AND COMBUSTION 22
AIR INTAKE
H. DIRECT VENTING THROUGH A SIDEWALL 24
I. INSTALLATION OF OUTSIDE EXHAUST/INTAKE TERMINATIONS 27
J. CONNECTING THE FURNACE TO ROOF VENT/ INTAKE TERMINATIONS 28
K. CONDENSATE DRAIN LINE AND TRAP ASSEMBLY 30
L. ELECTRICAL WIRING 31
V. STARTING THE UNIT 41
A. SEQUENCE OF OPERATION 41
B. INITIAL START-UP 43
C. ADJUSTMENT OF BTU INPUT RATE 44
D. BURNER ADJUSTMENT 45
E. SETTING TEMPERATURE RISE 46
F. FURNACE CHECK-OUT PROCEDURE 47
VI. INSTALLER'S INSTRUCTIONS TO USER 48
VII. DEALER MAINTENANCE 48
A. ELECTRICAL 49
B. GENERAL INSPECTION 49
C. HEAT EXCHANGER 50
D. HOUSE AIR BLOWER 50
E. RETURN AIR FILTER 50
VIII. TROUBLE SHOOTING 51
APPENDIX-A REPLACEMENT PARTS 58
APPENDIX-B WIRING DIAGRAM 62
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.
1
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.

All installations and services must be performed by qualified service personnel.
2
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.

All installations and services must be performed by qualified service personnel.
3
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.

All installations and services must be performed by qualified service personnel.
4
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/ANSI-
Z233.1 (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.

All installations and services must be performed by qualified service personnel.
5
: 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/CMC 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.

All installations and services must be performed by qualified service personnel.
6
: 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 start-
up 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/CMC 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.

All installations and services must be performed by qualified service personnel.
7
II. FURNACE SPECIFICATIONS
MODEL CMA3-50D36 CMA3-75D36
INPUT IN BTUH 50,000 75,000
OUTPUT IN BTUH 48,000 72,000
MAIN ORIFICE-NAT. #42
MAIN ORIFICE-LP #54
GAS SUPPLY PRESSURE
L.P. MINIMUM 11” IN.W.C.
NAT. MINIMUM 4.5”IN.W.C.
L.P. MAXIMUM 14” IN.W.C.
NAT. MAXIMUM 14” IN.W.C.
GAS MANIFOLD PRESSURE
L.P. 10.0” + .03 IN.W.C.
NAT. 3.5” + .03 IN. W.C.
INTAKE SIZE IN INCHES 2”
VENT SIZE IN INCHES 2”
NOMINAL TEMPERATURE RISE 55°F 65°F
SEASONAL EFFICIENCY (AFUE*) 95%
*ANNUAL FUEL UTILIZATION
EFFICIENCY
DIMENSIONS
CABINET SIZE WIDTH 18” DEPTH 25-3/4" HEIGHT 57"
SUPPLY AIR OUTLET WIDTH 12” DEPTH 12"
ELECTRICAL SUPPLY 115 VOLTS-- 60HZ --1/PH
FUSE OR HACR BREAKER 15 AMPS
TOTAL CURRENT AMPS 7.15 AMPS
NOMINAL ANTICIPATOR SETTING 0.8 MILLIAMPS
FILTER SIZE (1) 18” X 24” X 1”
APPROXIMATE SHIPPING WEIGHT 175 LBS. 185 LBS.
BLOWER DATA
BLOWER MODEL 12-9T DIRECT DRIVE
MOTOR HORSEPOWER 1/2 PSC
MOTOR RPM 1065 (HIGH SPEED)
CFM @ .2 & .5 IN. W.C. SPEED .2” .5” | .2” .5”
LOW 805 695 | 797 668
MD-LOW 1010 860 | 995 869
MD-HIGH 1196 1038 | 1210 1076
HIGH 1338 1162 | 1420 1259
FOR BURNER COMBUSTION INFORMATION REFER TO INITIAL STARTUP.

All installations and services must be performed by qualified service personnel.
8
MODEL CMC1-50D36 CMC1-75D36
INPUT IN BTUH 50,000 75,000
OUTPUT IN BTUH 48,000 72,000
MAIN ORIFICE-NAT. #42
MAIN ORIFICE-LP #54
GAS SUPPLY PRESSURE
L.P. MINIMUM
11” IN.W.C.
NAT. MINIMUM
4.5”IN.W.C.
L.P. MAXIMUM 14” IN.W.C.
NAT. MAXIMUM 14” IN.W.C.
GAS MANIFOLD PRESSURE
L.P. 10.0” + .03 IN.W.C.
NAT. 3.5” + .03 IN. W.C.
INTAKE SIZE IN INCHES
2”
VENT SIZE IN INCHES 2”
NOMINAL TEMPERATURE RISE 55°F 65°F
SEASONAL EFFICIENCY (AFUE*) 95%
*ANNUAL FUEL UTILIZATION
EFFICIENCY
DIMENSIONS
CABINET SIZE WIDTH 18-3/4” DEPTH 25-3/4" HEIGHT 76-1/8"
SUPPLY AIR OUTLET WIDTH 12” DEPTH 12"
ELECTRICAL SUPPLY 115 VOLTS-- 60HZ --1/PH
FUSE OR HACR BREAKER 15 AMPS
TOTAL CURRENT AMPS 7.15 AMPS
NOMINAL ANTICIPATOR SETTING 0.8 MILLIAMPS
FILTER SIZE (1) 18” X 24” X 1”
APPROXIMATE SHIPPING WEIGHT 195 LBS. 205 LBS.
BLOWER DATA
BLOWER MODEL 12-9T DIRECT DRIVE
MOTOR HORSEPOWER 1/2 PSC
MOTOR RPM 1065 (HIGH SPEED)
CFM @ .2 & .5 IN. W.C. SPEED .2” .5” | .2” .5”
LOW 805 695 | 797 668
MD-LOW 1010 860 | 995 869
MD-HIGH 1196 1038 | 1210 1076
HIGH 1338 1162 | 1420 1259
FOR BURNER COMBUSTION INFORMATION REFER TO INITIAL STARTUP.

All installations and services must be performed by qualified service personnel.
9
MODEL CMC1-50DV3 CMC1-75DV3
INPUT IN BTUH 50,000 75,000
OUTPUT IN BTUH 48,000 72,000
MAIN ORIFICE-NAT. #42
MAIN ORIFICE-LP #54
GAS SUPPLY PRESSURE
L.P. MINIMUM
11” IN.W.C.
NAT. MI
NIMUM
4.5”IN.W.C.
L.P. MAXIMUM 14” IN.W.C.
NAT. MAXIMUM 14” IN.W.C.
GAS MANIFOLD PRESSURE
L.P. 10.0” + .03 IN.W.C.
NAT. 3.5” + .03 IN. W.C.
INTAKE SIZE IN INCHES
2”
VENT SIZE IN INCHES 2”
NOMINAL TEMPERATURE RISE 55°F 65°F
SEASONAL EFFICIENCY (AFUE*) 95%
*ANNUAL FUEL UTILIZATION
EFFICIENCY
DIMENSIONS
CABINET SIZE WIDTH 18-3/4” DEPTH 25-3/4" HEIGHT 76-1/8"
SUPPLY AIR OUTLET WIDTH 12” DEPTH 12"
ELECTRICAL SUPPLY 115 VOLTS-- 60HZ --1/PH
FUSE OR HACR BREAKER 15 AMPS
TOTAL CURRENT AMPS 7.15 AMPS
NOMINAL ANTICIPATOR SETTING 0.8 MILLIAMPS
FILTER SIZE (1) 18” X 24” X 1”
APPROXIMATE SHIPPING WEIGHT 195 LBS. 205 LBS.
BLOWER DATA
BLOWER MODEL 12-9T DIRECT DRIVE
MOTOR HORSEPOWER 1/2 ECM
MOTOR RPM 1075 (HIGH SPEED)
CFM @ .2 & .5 IN. W.C. SPEED .2” .5” | .2” .5”
LOW 639 437 | 935 802
MD-LOW 834 653 | 998 880
MED 948 811 1113 1007
MD-HIGH 1145 1026 | 1177 1083
HIGH 1365 1265 | 1272 1177
FOR BURNER COMBUSTION INFORMATION REFER TO INITIAL STARTUP.

All installations and services must be performed by qualified service personnel.
10
INSTALLATION PARTS PACKAGES
PARTS PKG#
DESCRIPTION
CMA3-50D36N CMA3-75D36N
S00S4248 S00S4249
PART # QTY PART # QTY
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 AOPS7741 1 AOPS7742 1
PARTS PKG#
DESCRIPTION
CMC1-50D36N CMC1-75D36N
S00S4190 S00S4191
PART # QTY PART # QTY
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 AOPS7741 1 AOPS7742 1
Gasket, drain knock-out 330355 1 330355 1
Grommet, vinyl 3/8" 350040 1 350040 1
Grommet, vinyl 7/8" 350009 1 350009 1
Screw, #8 x 1/2 Tek 300208 6 300208 6
Coil trim panel 619113 1 619113 1
Bushing, UB-875 350750 1 350750 1
Bushing, SR-34-2 350016 1 350016 1
PARTS PKG#
DESCRIPTION
CMC1-50DV3N CMC1-75DV3N
S00S4244 S00S4245
PART # QTY PART # QTY
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 AOPS7741 1 AOPS7742 1
Gasket, drain knock-out 330355 1 330355 1
Grommet, vinyl 3/8" 350040 1 350040 1
Grommet, vinyl 7/8" 350009 1 350009 1
Screw, #8 x 1/2 Tek 300208 6 300208 6
Coil trim panel 619113 1 619113 1
Tape, aluminum 2" 390111 42" 390111 42"
Bushing, UB-875 350750 1 350750 1
Bushing, SR-34-2 350016 1 350016 1

All installations and services must be performed by qualified service personnel.
11
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-815 in Gas Conversion Kit
AOPS7743.
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. For the Energy Star Eco Tech models the temperature rises are 40°F to
70°F for the 50 series and 50°F to 80°F for the 75 series. (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
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.

All installations and services must be performed by qualified service personnel.
12
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 “NON-
COMBUSTIBLE 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.
MODELS CMA
3/CMC1
CLOSET ALCOVE
FRONT
BACK
SIDES
VENT CONNECTOR(PVC)
TOP
PLENUM SIDES
TOP AND SIDES OF DUCT
BOTTOM OF DUCT
6”
0”
0”
0”
0”
1”
1”
1”
18”
0”
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.

All installations and services must be performed by qualified service personnel.
13
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. Model CMA3 furnace may be installed on a combustible floor when utilizing
either the No. 70 counterflow floor base or CE113S / CE213T 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.
4. Model CMC1 furnace is designed to be installed directly on a combustible
floor and is not required to be installed on a base.
This furnace is ETL listed for closet, alcove or free standing applications. All
applications must comply with the requirements of this manual.
Combustible Floor Base Model: 70-BASE
For CMA3 models only.
Figure 1A.

All installations and services must be performed by qualified service personnel.
14
Coil Cabinet Model: CE113S / CE213T
Note: Coil cabinet cannot be utilized as a cottage base.
CE113S CE213T
Figure 1B.
Cottage Base Model: 01COT-BASE
For CMA3 models only.
NOTE: Serves as a plenum for single story applications with exposed supply air
systems.
Figure 1C.

All installations and services must be performed by qualified service personnel.
15
B. BASE INSTALLATION – CMA3 models only
1. Combustible Floor Base Model: 70 BASE (for CMA3 models only)
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.

All installations and services must be performed by qualified service personnel.
16
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
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 (for CMA3 models only)
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.
The model CMC does not require a base for installation. The integrated coil
cabinet serves as a base. The duct connection will be made to the bottom of the
furnace. A sheet metal cover plate may be installed to protect any exposed
combustible flooring.

All installations and services must be performed by qualified service personnel.
17
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.
CMA3 SERIES CMC1 SERIES
Figure 4.
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.

All installations and services must be performed by qualified service personnel.
18
CMA3 SERIES CMC1 SERIES
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).