Carrier JK034-074, 50FK, 48FK specifications Ð Diagnostic Codes

Diagnostic Codes Ð Diagnostic codes are warnings of abnormal or fault conditions, and may cause either one circuit or the whole unit to shut down. They are assigned code numbers as described below.

Table 22 contains a description of each diagnostic code error and possible cause. Manual reset is accomplished by moving the ON/OFF Switch to the OFF position, then back to ON.

The 2-digit LED display is used to display the diagnostic codes and the alarm light (located next to display) is ener- gized whenever a diagnostic code is tripped. When a prob- lem is suspected, always check the display ®rst for diagnos- tic information.

NOTE: Codes 53, 54, 57, 58, 61, 62, 65-69, 73, 74, and 77-80 are not used on these units.

IMPORTANT: The microprocessor memory and the display will be cleared if the power to the microproces- sor is shut off. DO NOT attempt to bypass, short, or modify the control circuit or electronic boards in any way to correct a problem. This could result in a haz- ardous operating condition.

CODES 51, 52, 55, 56: COMPRESSOR FAILURE Ð If con- trol relay (CR) opens while compressor should be operating, compressor will stop and microprocessor will energize alarm

light and display a code of 51 , 52 , 55 or 56 (de-

pending on compressor) when display button is pushed. The compressor will be locked off; to reset, the ON-OFF switch must be turned to OFF and then to ON position.

If lead compressor in a refrigerant circuit is shut down, the other compressor in that circuit will also be shut down and locked off. Only the error code for the lead compressor will be displayed.

Code 51 is for compressor 1, and Code 55 is for com- pressor 2. Codes 52 and 56 are used for compressors 3 and 4, respectively, on size 104 units.

The microprocessor has also been programmed to indi- cate a compressor failure if CR switch is closed when com- pressor is not supposed to be on.

If a failure occurs, the following are possible causes:

High-Pressure Switch Open Ð The high-pressure switch for each compressor is wired in series with 24-v power that en- ergizes CR. If high-pressure switch opens during operation, CR will stop compressor and this will be detected by micro- processor through the feedback contacts.

Internal Thermostat Ð The internal thermostat in each 06D compressor is also wired in series with 24-v power that en- ergizes CR. If thermostat fails or switch opens during op- eration of compressor, compressor will shut down and fail- ure is detected through feedback contacts (size 034 and 038 only).

CR Failure Ð If CR fails with large relay either open or closed, microprocessor will detect this, lock compressor off, and in- dicate an error.

Relay Board Failure Ð If small 24-v relay on the relay board fails, microprocessor will detect this through feedback con- tacts and indicate an error.

Processor Board Failure Ð If hardware that monitors feed- back switch fails and processor board fails to energize the relay board relay to ON position, an error may be indicated.

The control does not detect compressor circuit breaker failures.

Wiring Problem Ð A wiring error or a loose wire may cause the feedback circuit to be broken.

Table 22 Ð Diagnostic Codes

DISPLAY	DESCRIPTION OF FAILURE	ACTION TAKEN	RESET	PROBABLE CAUSE
		BY CONTROL	METHOD
51	Compressor 1 failure	Circuit 1 shut off	Manual	High-pressure switch or high dis-
55	Compressor 2 failure	Circuit 2 shut off	Manual	charge gas thermostat switch
52	Compressor 3 failure	Compressor 3 shut off	Manual	trip, compressor ground current
56	Compressor 4 failure	Compressor 4 shut off	Manual	. 2.5 amp or compressor board
				relay on when it is not supposed
				to be on. Wiring error between
				electronic control and compres-
				sor protection module.
59	Loss-of-charge circuit 1	Circuit 1 shut off	Manual	This indicates either a low refrig-
60	Loss-of-charge circuit 2	Circuit 2 shut off	Manual	erant charge, or a loss-of-charge
				switch failure.
63	Low oil pressure circuit 1	Circuit 1 shut off	Manual	Not used; Check jumper on pro-
64	Low oil pressure circuit 2	Circuit 2 shut off	Manual	cessor board.
70	Illegal unit con®guration	Unit will not start	Manual	Con®guration error (see Note 1).
71	Supply-air thermistor failure	Unit shut off	Auto.	Thermistor or resistor failure, wir-
72	Return-air thermistor failure	Use default value	Auto.	ing error, or thermistor or resistor
75	Circuit 1 saturated condensing thermistor	Unit shut off	Auto.	not connected to the processor
76	Circuit 2 saturated condensing thermistor	Unit shut off	Auto.	board.
81	Reset temperature thermistor failure	Stop reset	Auto.
82	Leaving-air set point potentiometer failure	Use default value	Auto.	Potentiometer improperly con-
83	Economizer potentiometer failure	Close economizer	Auto.	nected, potentiometer setting out
84	Reset limit set point potentiometer failure	Stop reset	Auto.	of range, potentiometer failure or
85	Demand limit potentiometer failure	Stop demand limit	Auto.	wiring error.
86	Minimum economizer potentiometer failure	Close economizer	Auto.
87	Warm-up set point potentiometer failure	Use default value	Auto.

NOTES:

1.Illegal unit con®guration caused by missing programmable header or both unloader DIP switches on.

2.All auto. reset failures that cause the unit to stop will restart when the error has been corrected.

3.All manual reset errors must be reset by turning the control switch off and then back on.

4.Valid resistance range for the thermistors is 363,000 to 585 ohms.

5.Codes 53, 54, 57, 58, 61, 62, 65-69, 73, 74, and 77-80 are not used on these units.

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