Thermo Products CMA2-75N, CMA1-50N service manual Electrical Wire Diameter AWG 24 22 20 18

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Electrical Wire Diameter

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

NOTE: Class 1 thermostat wire must be used inside the furnace burner compartment.

a.Insert 24 VAC wires through the plastic grommet on the left side of the furnace casing.

b.Connect the thermostat wires to the W/R 50A65-143 control (refer to the wiring diagram).

c.Connect the thermostat wires to the room thermostat.

IMPORTANT: The room thermostat should be installed 4 to 5 feet above the floor on an interior wall which is relatively free from direct sources of heat (sunlight or supply airflow) or exposure to cold (drafts from open windows and doors). The nominal anticipator setting is 0.8 amperes, for the CMA (refer to the thermostat literature for additional information).

Four-conductor thermostat wire is recommended for 24 VAC, low-voltage, control circuit wiring. How ever only 2 wires are required for the furnace (a heating application only).

Electrical Wire Diameter

(AWG)

24

22

20

18

Maximum Recommended

Thermostat Wire Length

(Feet)

55

90

140

225

Once the furnace is installed, check the thermostat anticipator for proper nominal setting.

1.Connect a multimeter, capable of reading milliamps (mA), in series with the low voltage wires to the thermostat.

2.Increase the thermostat setting, or create a “call for heat”.

3.Read the value of the thermostat current, in milliamps.

4.Adjust the heat anticipator of the thermostat to the value read by the multimeter.

If the heat anticipator is set too high, the furnace may delay activation of a heating cycle for too long. If the heat anticipator is set too low, the furnace may cycle too frequently. Either condition may not provide optimal comfort to the homeowner.

NOTICE: The hot surface igniter and operation of this furnace depends on correct polarity. The hot leg of the supply circuit must be connected to the black line lead (L1) and the common leg (L2) to the white line lead in the field

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Contents GAS FIRED HIGH EFFICIENCY FURNACE INSTALLATION AND SERVICE MANUALFOR YOUR SAFETY DOWN FLOW & DIRECT VENT SEALED COMBUSTIONTABLE OF CONTENTS SECTIONI. SAFETY INFORMATION Page Page 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 1.A windows be opened MODEL II. FURNACE SPECIFICATIONS - CMA SERIESDIMENSIONS GAS SUPPLY PRESSUREINSTALLATION PARTS PACKAGE COMBUSTIBLE MATERIAL.” COMBUSTIBLE MATERIAL NON-COMBUSTIBLEMATERIALIV. GENERAL INSTALLATION A.FURNACE LOCATION MODELS CMATable Combustible Floor Base Model: 70-BASE Figure 1A Coil CabinetFigure 1B Cottage Base Model: 01COT-BASE Figure 1C B. BASE INSTALLATION 1. Combustible Floor Base Model: 70 BASEFigure Figure C. ALCOVE INSTALLATION 2. Cottage Base Model: 01COT BASEFigure D. CLOSET INSTALLATION FigureE. FUEL PIPING F.GENERAL VENTING REQUIREMENTS MAXIMUM VENT LENGTH TableFigure 6. CMA*-75SHOWN H. Direct Venting Through a Sidewall 1. Vent And Combustion Air Pipes2. Exhaust Vent Termination Elbow Sidewall Venting Page 4. Vent Terminal Location Guidelines Terminations 5.Secure plate to roof Figure FigureFigure K.CONDENSATE DRAIN LINE AND TRAP ASSEMBLY 3.Connection Of Room Thermostat Wires Figure L.ELECTRICAL WIRING2.Connection Of Power Supply Wires 1. Electrical Branch Supply CircuitElectrical Wire Diameter AWG 24 22 20 18 4. BLOWER MOTOR SPEED WIRING Figure Static CMA1-50Speed Tap \ PressureStatic CMA2-75Speed Tap \ Pressure5. FIELD WIRING AND REPLACING WIRING V.STARTING THE UNIT A. SEQUENCE OF OPERATIONS MAIN BURNER OPERATION CALL FOR HEAT SATISFIED B.INITIAL START UP OPERATING INSTRUCTIONSC.ADJUSTMENT OF BTU INPUT RATE GAS PRESSURE CHART FOR CMA* MODEL FURNACES D.BURNER ADJUSTMENTE.SETTING TEMPERATURE RISE FigureF.FURNACE CHECKOUT PROCEDURE VI. INSTALLERS INSTRUCTIONS TO USER VII. DEALER MAINTENANCEA.ELECTRICAL 2.CONDENSATE LINE/TRAP ASSEMBLY4. INDUCER BLOWER ASSEMBLY B.GENERAL INSPECTIONC.HEAT EXCHANGER 1.CLEANING THE COIL AIR SIDE5. GASKETS/SEALING MATERIALS D.HOUSE AIR BLOWERVIII. TROUBLESHOOTING FILTER MAINTENANCE PROCEDUREFILTER REPLACEMENT DIAGNOSTIC FEATURESThe LED will also flash once at power-up TROUBLESHOOTING GUIDE AT THE INTEGRATED CONTROL? Yes AFTER GAS VALVE OPENS, DO THE BURNERS IGNITE? DOES SYSTEM RUN UNTIL THERMOSTAT IS SATISFIED? IF LED LIGHT FLASHES APPENDIX – A REPLACEMENT PARTS Page APPENDIX – B WIRING DIAGRAM