Carrier 48FK, JK034-074, 50FK Ð Operation Status Codes, Ð Controls Troubleshooting

TROUBLESHOOTING

By using the display module, actual operating conditions of the unit are displayed while it is running. The Quick Test function allows proper operation of compressors, compres- sor unloaders, fans, and other components to be checked while unit is stopped. If an operating fault is detected, an alarm is generated and an alarm code(s) is displayed. For checking speci®c items, see Table 20.

Checking Display Codes Ð To view the digital dis- play codes, press the button located to the right of the LED display/set point board in the control box. See Table 21 for Operational Status Codes. See Table 22 for Diagnostic Codes.

Complete Unit Stoppage Ð If the unit is off, there are several conditions that can cause this situation to occur:

·Remote ON/OFF circuit in Unoccupied mode.

·Unit ON/OFF switch moved to OFF position.

·Programmed schedule at the timeclock.

·General power failure.

·Blown fuse in the control power feed.

·Open control circuit fuse.

·Operation of the unit blocked by the demand limit function.

·Unit supply-air temperature (T1) thermistor failure.

·Supply-air fan is not operating.

·High duct static pressure.

Single Circuit Stoppage Ð If a single circuit stops, there are several potential causes:

·Open contacts in the compressor high-pressure switch.

·Low refrigerant pressure.

·Thermistor failure.

·Unit supply-air temperature thermistor (T1) failure.

·Compressor circuit breaker trip.

·Operation of the circuit blocked by the demand limit function.

Table 21 Ð Operation Status Codes

CODE	MEANING
0	0 cooling stages active
1	1 cooling stage active
2	2 cooling stages active
3	3 cooling stages active
4	4 cooling stages active
5	5 cooling stages active
6	6 cooling stages active
7	7 cooling stages active
8	8 cooling stages active
	Initialization mode (Allow 2 minutes
20	for initialization. To initiate Quick Test,
	press the Display button while 20 is displayed.)
21	Temperature Reset in effect
22	Demand Limit in effect
26	Morning Warm-Up in effect
30	Internal failure detected
88	Self-diagnostic mode in effect

Restart Procedure Ð Before attempting to restart the machine, check the display for alarm codes to determine the cause of the shutdown. If the unit, circuit, or compressor stops more than once as a result of a safety device, determine and correct the cause before attempting to start the unit again.

After the cause of the shutdown has been corrected, unit restart may be automatic or manual depending upon the fault.

Table 20 Ð Controls Troubleshooting

SYMPTOM(S)		PROBABLE CAUSE(S)		SOLUTION(S)
Controls do not seem	Remote on-off function may be		Check status.
to be operating.	keeping controls off.
Evaporator fan does not run.	1.	Circuit breaker open.	1.	Find cause and reset circuit breaker.
	2.	Inverter overload (if equipped).	2.	Find cause and reset.
Compressor does not run.	1.	Circuit breaker is open.	1.	Find cause and reset circuit breaker.
	2.	There is no demand for cooling.	2.	Correct operation.
	3.	The control is locking out cooling operation.	3.	Check rotating display for alarm codes. Resolve
				alarm cause and reset control by changing to
				standby and back to run mode.
	4.	Demand Limit in effect.	4.	Check Demand Limit Settings.
Condenser fans do not	Circuit breaker is open.		Find cause and reset circuit breaker
turn on.
Cooling demand exists and	Compression cannot be initiated		Correct operation.
economizer modulates, but	until economizer damper is 90% open.
compression is not operating.

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