Carrier 50VT-A installation instructions Troubleshooting Chart, Symptom Cause Remedy

50VT-- 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, or high--pressure,	Replace component
Compressor and condenser fan will not start.	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 high	Lower thermostat setting below room tempera-
		ture
	Faulty wiring or loose connections in compressor cir-	Check wiring and repair or replace
	cuit
Compressor will not start but condenser fan	Compressor motor burned out, seized, or	Determine cause
	internal overload open	Replace compressor
runs
	Defective run/start capacitor, overload, start relay	Determine cause and replace
	One leg of 3--phase power dead	Replace fuse or reset circuit breaker
		Determine cause
Three-phase scroll compressor		Correct the direction of rotation by reversing the
makes excessive noise, and there may be a	Scroll compressor is rotating in the wrong direction
		3--phase power leads to the unit.
low pressure differential.
	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 sat-	Insufficient line voltage	Determine cause and correct
	Blocked condenser	Determine cause and correct
isfying thermostat).
	Defective run/start capacitor, overload or start relay	Determine cause and replace
	Defective thermostat	Replace thermostat
	Faulty condenser--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 set too low	Reset thermostat
Compressor operates continuously	Low refrigerant charge	Locate leak, repair, and recharge
	Mechanical damage in compressor	Replace compressor
	Air in system	Recover refrigerant, evacuate system, and re-
		charge
	Condenser coil dirty or restricted	Clean coil or remove restriction
	Dirty air filter	Replace filter
	Dirty condenser coil	Clean coil
Excessive head pressure	Refrigerant overcharged	Recover excess refrigerant
	Air in system	Recover refrigerant, evacuate system, and re-
		charge
	Condenser air restricted or air short--cycling	Determine cause and correct
	Low refrigerant charge	Check for leaks, repair, and recharge.
Head pressure too low	Compressor IPR leaking	Replace compressor
	Restriction in liquid tube	Remove restriction
	High heat load	Check for source and eliminate
Excessive suction pressure	Compressor IPR leaking	Replace compressor
	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 evaporator airflow	Increase air quantity
		Check filter–replace if necessary
	Temperature too low in conditioned area	Reset thermostat
	Outdoor ambient below 55°F (12.7°C)	Install low--ambient kit
	Filter drier restricted	Replace filter

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