Carrier 50VL---A installation instructions Troubleshooting Chart, 50VL--A

50VL-- A

Table 10 – 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, or high--	Replace component
Compressor and outdoor fan will not start	pressure, loss--of--charge or low--pressure switch
	Insufficient line voltage	Determine cause and correct
	Incorrect or faulty wiring	Check wiring diagram and rewire correctly
	Thermostat setting too low/too high	Reset thermostat setting
	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	Determine cause and correct
Three-phase scroll compressor (size 30-	Scroll compressor is rotating in the wrong direction	Correct the direction of rotation by reversing the
60 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	Insufficient line voltage	Determine cause and correct
satisfying) cooling/heating calls	Blocked outdoor coil	Determine cause and correct
	Defective run/start capacitor, overload or start relay	Determine cause and replace
	Faulty outdoor fan motor or capacitor	Replace
	Restriction in refrigerant system	Locate restriction and remove
	Dirty air filter	Replace filter
	Unit undersized for load	Decrease load or increase unit size
	Thermostat temperature set too low	Reset thermostat setting
Compressor operates continuously	Low refrigerant charge	Locate leak, repair, and recharge
	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
Excessive head pressure	Refrigerant overcharged	Recover excess refrigerant
	Air in system	Recover refrigerant, evacuate system, and re-
		charge
	Indoor or outdoor air restricted or air short--cycling	Determine cause and correct
Head pressure too low	Low refrigerant charge	Check for leaks, repair and recharge
	Restriction in liquid tube	Remove restriction
Excessive suction pressure	Refrigerant overcharged	Recover excess refrigerant
	Dirty air filter	Replace filter
	Low refrigerant charge	Check for leaks, repair and recharge
	Metering device or low side restricted	Remove source of restriction
Suction pressure too low	Insufficient coil airflow	Check filter–replace if necessary
	Temperature too low in conditioned area	Reset thermostat setting
	Outdoor ambient below 55°F (13°C)	Install low--ambient kit
	Filter drier restricted	Replace

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