Carrier 48TC*D08 appendix Cooling Service Analysis, Problem Cause Remedy

48TC

Table 1 – Cooling Service Analysis

PROBLEM	CAUSE	REMEDY
	Power failure.	Call power company.
	Fuse blown or circuit breaker tripped.	Replace fuse or reset circuit breaker.
Compressor and Condenser	Defective thermostat, contactor, transformer,	Replace component.
	or control relay.
Fan Will Not Start.
	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 temperature.
	Faulty wiring or loose connections in	Check wiring and repair or replace.
	compressor circuit.
	Compressor motor burned out, seized, or	Determine cause. Replace compressor.
Compressor Will Not Start But	internal overload open.
Condenser Fan Runs.
	Defective run/start capacitor, overload, start	Determine cause and replace.
	relay.
	One leg of three---phase power dead.	Replace fuse or reset circuit breaker. Determine
		cause.
	Refrigerant overcharge or undercharge.	Recover refrigerant, evacuate system, and recharge
		to nameplate.
	Defective compressor.	Replace and determine cause.
Compressor Cycles (other	Insufficient line voltage.	Determine cause and correct.
	Blocked condenser.	Determine cause and correct.
than normally satisfying
	Defective run/start capacitor, overload, or start
thermostat).		Determine cause and replace.
	relay.
	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.
Compressor Operates	Thermostat set too low.	Reset thermostat.
	Low refrigerant charge.	Locate leak; repair and recharge.
Continuously.
	Leaking valves in compressor.	Replace compressor.
	Air in system.	Recover refrigerant, evacuate system, and recharge.
	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 recharge.
	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 valves leaking.	Replace compressor.
	Restriction in liquid tube.	Remove restriction.
	High head load.	Check for source and eliminate.
Excessive Suction Pressure.
	Compressor valves 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 and replace if
		necessary.
	Temperature too low in conditioned area.	Reset thermostat.
	Outdoor ambient below 25° F.	Install low--- ambient kit.
Evaporator Fan Will Not Shut	Time off delay not finished.	Wait for 30--- second off delay.
Off.
Compressor Makes Excessive	Compressor rotating in wrong direction.	Reverse the 3--- phase power leads.
Noise.

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