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

FILTER MAINTENANCE PROCEDURE 

 
The filter is located inside front door of the CMA. Remove filter retaining rod and 
remove dirty filter. Clean the filter by vacuuming, rinsing with tap water, hosing or 
dipping in an ordinary detergent solution. After cleaning, replace the completely 
dry filter and retain with retaining rod. If the filter has a mesh, the mesh side of 
the filter must be towards the furnace. 

 
FILTER REPLACEMENT 

 

Should the filter require replacement, replace with like size and type filter as 
originally supplied with furnace. 

 
IMPORTANT:  

Remind homeowner of importance of monthly filter inspections 

during the heating season to ensure efficient and trouble-free operation of their 
furnace. 

 
VIII.  TROUBLESHOOTING 
 

NOTICE:  BEFORE TROUBLESHOOTING, FAMILIARIZE YOURSELF WITH THE 
START UP AND CHECKOUT PROCEDURE. 

 

ALL INSTALLATION AND SERVICES MUST BE PERFORMED BY QUALIFIED 
HEATING CONTRACTORS.

 

 
To assist you in troubleshooting this furnace, it is equipped with an integrated 
ignition control with diagnostics. These diagnostics evaluate what control system has 
experienced a failure and will activate a flashing light on the control in different 
sequences to help pinpoint the failure which has occurred. 
 
Note – check diagnostic code through view port prior to removing access door. 

 
DIAGNOSTIC FEATURES 
 

The 50A65 control used on this furnace continuously monitors its operation and the 
operation of the system. If a failure occurs, the LED light on the control will flash a 
code. 

If the failure is internal to the control, the light will stay on continuously. 

In this case, the entire control should be replaced, as the control is not field-
repairable. 

 
If the sensed failure is in the system (external to the control), the LED will flash in the 
following flash-pause sequences to indicate failure status (each flash will last 
approximately 0.25 seconds, and each pause will last approximately 2 seconds). 
 
1 flash, then pause 

 

 

system locked 

2 flashes, then pause   

pressure switch stuck closed 

 

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Summary of Contents for CMA1-50N

Page 1: ...ons 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 o...

Page 2: ...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...

Page 3: ...ualified 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 Pleas...

Page 4: ...formed 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 c...

Page 5: ...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 co...

Page 6: ...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 furn...

Page 7: ...ce 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...

Page 8: ...NSIONS CABINET SIZE SUPPLY AIR OUTLET ELECTRICAL SUPPLY FUSE OR HACR BREAKER TOTAL CURRENT AMPS NOMINAL ANTICIPATOR SETTING FILTER SIZE APPROXIMATE SHIPPING WEIGHT BLOWER DATA BLOWER MODEL MOTOR HORSE...

Page 9: ...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 f...

Page 10: ...an 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 investi...

Page 11: ...zed 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 A...

Page 12: ...lations 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 Fi...

Page 13: ...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 system...

Page 14: ...pening 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 combu...

Page 15: ...he 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 silico...

Page 16: ...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...

Page 17: ...nnection 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 dop...

Page 18: ...must be installed with outside combustion air 3 The flue vent pipe and combustion air pipe must be at least as large as the exhaust vent air intake pipe specified by Thermo Products No reduction in s...

Page 19: ...e PVC sleeve or coupling to the metal air intake collar on the burner box The screw securing the sleeve or coupling to the collar is sufficient 7 Use the two radiator hose clamps to connect both the e...

Page 20: ...vent pipe must be supported every 4 feet After making sure the length of the piping is correct glue all connections in place This CMA furnace has been designed to be installed as a direct vent system...

Page 21: ...tion or its equivalent 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 vapo...

Page 22: ...t vent termination elbow shall be installed in accordance with these instructions and any applicable local codes Refer to Figures 7 and 8 for typical examples of proper terminations a The exhaust vent...

Page 23: ...rom or 12 inches above any door window or gravity air inlet into a building The bottom of the vent terminal shall be located at least 12 inches above grade c The vent terminal shall not be located ove...

Page 24: ...All installations and services must be performed by qualified service personnel Figure 9 NFGC Minimum Clearances Between the Vent Terminal and Various Building Features 22...

Page 25: ...ombustion air terminations shall be checked periodically at least at the start of each heating season for restriction or blockage from foreign material in the exhaust vent or in the air intake piping...

Page 26: ...eel screen is available from Thermo Products under part no 320219 J CONNECTING THE FURNACE TO ROOF VENT AIR TERMINATIONS The CMA is designed to be vented with either a concentric vent assembly or twin...

Page 27: ...the roof The outlet inlet of the vent and air intake terminations shall be a minimum of 12 inches above highest anticipated snow level The vent outlet must be installed a minimum of 12 in above the a...

Page 28: ...the fire stop far enough to engage a PVC coupling that will rest on the fire stop and act as a support Seal between the pipe coupling and fire stop with high temperature RTV silicone sealant see Figu...

Page 29: ...TION 1 Electrical Branch Supply Circuit Route all electrical wiring to the left side of the furnace The power supply circuit to the furnace must be installed and grounded in accordance with the provis...

Page 30: ...only 2 wires are required for the furnace a heating application only Electrical Wire Diameter Maximum Recommended Thermostat Wire Length AWG Feet 24 55 22 90 20 140 18 225 Once the furnace is installe...

Page 31: ...grounded in accordance with local codes and with the National Electrical Code ANSI NFPA NO 70 Latest Edition when an external electrical source is utilized 4 BLOWER MOTOR SPEED WIRING Figure 15 BLOWER...

Page 32: ...e Rise vs External Static Pressure in WC Speed Tap Static Pressure 0 1 0 2 0 3 0 4 0 5 0 6 0 7 Low 53 55 57 59 63 71 78 ML 42 44 45 48 51 53 59 MH 35 37 38 40 42 45 49 High 31 33 34 36 38 41 44 Blower...

Page 33: ...rature Rise vs External Static Pressure in WC Speed Tap Static Pressure 0 1 0 2 0 3 0 4 0 5 0 6 0 7 Low 81 83 85 90 90 106 119 ML 65 66 69 72 76 80 87 MH 52 55 56 59 61 64 69 High 45 46 48 50 52 55 59...

Page 34: ...odule to obtain the desired CFM The unused speeds should then be reconnected to the module in the park positions Refer to figure 15 Refer to section II for blower speed and air flow performance for A...

Page 35: ...INTERRUPTION SYSTEM SHUTS OFF RESTARTS WHEN POWER IS RESTORED PRESSURE SWITCH SENSES ADEQUATE DIFFERENTIAL PRESSURE CONTACTS CLOSE CONTROL BOARD ENERGIZED INDUCER ENERGIZED POWER IS APPLIED TO THE SI...

Page 36: ...THE GAS VALVE IS DE ENERGIZED AFTER PROOF OF FLAME LOSS INDUCER STARTS 5 SECOND POST SURGE AND OPTIONAL HUMIDIFIER ARE DE ENERGIZED THE DELAY TO FAN OFF PERIOD BEGINS 120 SECONDS IF SYSTEM IS IN LOCK...

Page 37: ...to the drain system OPERATING INSTRUCTIONS 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...

Page 38: ...rate for 10 to 15 minutes and proceed as follows 1 Call your gas supplier and ask for the BTU content heating value of one cubic foot of the gas supplied to the installation area An alternate approach...

Page 39: ...NOT EXCEED 0 3 WC A 0 3 WC adjustment will increase or decrease the input approximately 4 0 Replace screw cap when adjustment is complete The correct input can be assumed if the furnace manifold press...

Page 40: ...ch installation A lower temperature rise will result in a higher efficiency Temperature rise supply air temperature return air temperature After 10 to 15 minutes of continuous operation the temperatur...

Page 41: ...as follows a Shut off incoming power b Block return air opening or disconnect blower motor leads c Restore power to furnace d Set thermostat above room temperature calling for heat e When temperature...

Page 42: ...nd may void the limited warranty on the furnace 6 Review with and encourage the user to read the label reproductions and all warnings and instructions in this manual 7 Recommend that the user have a q...

Page 43: ...cted 2 CONDENSATE LINE TRAP ASSEMBLY The condensate line must be inspected to make sure it is not blocked All of the lines should be flushed with water to remove any build up of sediment 3 BURNERS If...

Page 44: ...ning being careful not to bend or damage any of the fins c Once all components are cleaned they must be re installed to their factory produced state Any seals or joints in the flue system which have b...

Page 45: ...PERFORMED BY QUALIFIED HEATING CONTRACTORS To assist you in troubleshooting this furnace it is equipped with an integrated ignition control with diagnostics These diagnostics evaluate what control sy...

Page 46: ...high limit switch 6 flashes then pause 115 volt AC power reversed 7 flashes then pause low flame sense signal 8 flashes then pause check ignitor or improper grounding Continuous flashing Flame has bee...

Page 47: ...K SERVICE SWITCH AND FUSES No CHECK FOR CONTINUITY PROPER CONNECTIONS No Yes Yes REPLACE TRANSFORMER No Yes Yes No No Yes ARE WIRES CONNECTED PROPERLY No CORRECT WIRE CONNECTIONS No Yes Yes No Yes IS...

Page 48: ...TERMINALS IND IND N AT THE INTEGRATED CONTROL CHECK THE INTEGRATED CONTROL DIAGNOSTIC LED LAMP RESET BY INTERRUPTING POWER TO CONTROL FOR MORE THAN ONE SECOND IF LED STAYS ON CONTINUOUSLY REPLACE INTE...

Page 49: ...FLAME CHECK Yes CHECK ACROSS THE CIRCULATING AIR BLOWER TERMINALS CIR N HEAT FOR PROPER VOLTAGE REPLACE THE INTEGRATED CONTROL No No Yes DOES THE CIRCULATING AIR FAN COME ON WHEN ENERGIZED No DOES BLO...

Page 50: ...ISFIED CHECK ALL WIRING FOR LOOSE CONNECTIONS CHECK FOR SHORT IN WIRE TO THERMOSTAT AND CORRECT IF NECESSARY DOES BURNER SHUT OFF WHEN THERMOSTAT IS SATISFIED No DOES THE CIRCULATING AIR BLOWER TURN O...

Page 51: ...K OPEN 4 FLASHES THEN PAUSE OPEN LIMIT SWITCH OR ROLLOUT SWITCH 6 FLASHES THEN PAUSE 115 VOLT AC POWER REVERSED 7 FLASHES THEN PAUSE LOW FLAME SENSE SIGNAL 8 FLASHES THEN PAUSE CHECK IGNITOR OR IMPROP...

Page 52: ...All installations and services must be performed by qualified service personnel APPENDIX A REPLACEMENT PARTS 50...

Page 53: ...All installations and services must be performed by qualified service personnel All installations and services must be performed by qualified service personnel 51 51...

Page 54: ...All installations and services must be performed by qualified service personnel APPENDIX B WIRING DIAGRAM 52...

Page 55: ...All installations and services must be performed by qualified service personnel 53...

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