Carrier 50CR installation instructions Troubleshooting Chart

50CR

Table 7—Troubleshooting Chart

SYMPTOM	CAUSE	REMEDY
	Power failure	Call power company
	Fuse blown or circuit breaker tripped	Replace fuse or reset circuit breaker
	Defective contactor, transformer, control relay, defrost	Replace component
	board, or high--pressure, loss--
	of--charge or low--pressure switch
Compressor and outdoor fan	Insufficient line voltage	Determine cause and correct
will not start	Incorrect or faulty wiring	Check wiring diagram and rewire correctly
	User Interface setting too low/too high	Reset UI setting
		DO NOT bypass this compressor time
	Units have a 5--minute time delay	delay–wait for 5 minutes until time--delay
		relay is de--energized
	Faulty wiring or circuit	Check wiring and repair or replace
	Loose connections in compressor
	Compressor motor burned out, seized, or	Determine cause
Compressor will not start but condenser fan	internal overload open	Replace compressor
	Defective run capacitor, overload, or PTC (positive
runs		Determine cause and replace
	temperature coefficient) thermistor
	One leg of 3--phase power dead	Replace fuse or reset circuit breaker
		Determine cause
	Low input voltage (20 percent low)	Determine cause and correct
Three-phase scroll compressor (size 030-	Scroll compressor is rotating in the wrong direction	Correct the direction of rotation by reversing the
060 unit) has a low pressure differential		3--phase power leads to the unit
	Refrigerant overcharge or undercharge	Recover refrigerant, evacuate system, and re-
		charge to capacities shown on rating plate
	Defective compressor	Replace and determine cause
Compressor cycles (other than normally satis-	Insufficient line voltage	Determine cause and correct
	Blocked outdoor coil	Determine cause and correct
fying) cooling/heating calls
	Defective run/start capacitor, overload or start relay	Determine cause and replace
	Faulty outdoor fan motor or capacitor	Replace
	Damaged reversing valve	Determine cause and correct
	Restriction in refrigerant system	Locate restriction and remove
	Dirty air filter	Replace filter
	Unit undersized for load	Decrease load or increase unit size
	UI temperature set too low/too high	Reset UI setting
	Low refrigerant charge	Locate leak, repair, and recharge
Compressor operates continuously		Check defrost time settings
	Frosted coil with incorrect defrost operation	Reset as necessary
		Check defrost temperature switch
		Replace as necessary
	Air in system	Recover refrigerant, evacuate system, and re-
		charge
	Outdoor coil dirty or restricted	Clean coil or remove restriction
	Dirty air filter	Replace filter
	Dirty indoor or outdoor coil	Clean coil
	Refrigerant overcharged	Recover excess refrigerant
Excessive head pressure
	Air in system	Recover refrigerant, evacuate system, and re-
		charge
	(Heat) Indoor air restricted or recirculating	Determine cause and correct
	Indoor or outdoor air restricted or air short--cycling	Determine cause and correct

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