Carrier 040-420 specifications Troubleshooting

			Table 17		- Troubleshooting
SYMPTOMS	CAUSE					REMEDY
COMPRESSOR DOES	Power	line open				Reset circuit breaker
NOT RUN	Control fuse open					Check control circuit for ground or short.
						Replace		fuse
	High Pressure Switch (HPS)					Move LOCAL/ENABLE-STOP-CCN switch to STOP
	tripped					position then back to RUN or CCN position.
	Tripped power breaker					Check the controls. Find cause of trip
						and reset breaker
	Loose	terminal		connection		Check connections
	Improperly wired controls					Check wiring and rewire.
	Low line		voltage			Check line voltage. Determine location
						of voltage drop and remedy deficiency
	Compressor motor defective					Check motor winding for open or shot-t.
						Replace compressor if necessary.
	Seized compressor					Replace compressor.
COMPRESSOR CYCLES OFF	Loss of charge					Repair leak and recharge
ON LOW PRESSURE	Bad transducer					Replace transducer.
	Low refrigerant charge					Add	refrigerant.
COMPRESSOR SHUTS DOWN	High-pressure control erratic in action					Replace		control
~N&-l;l;PFlESSURE	Compressor discharge valve partially closed					Open valve			or replace if defective.
	Condenser fan(s) not operating					Check wiring. Repair or replace motor(s)
						if defective.
	Condenser coil oluaaed				or dirtv	Clean	coil.
UNIT OPERATES LONG OR	Low refrigerant charge					Add	refrigerant,
CONTINUOUSLY	Control contacts fused					Replace		control
	Partially		plugged	or plugged expansion		Clean	or replace
	valve or filter driver
	Defective		insulation			Replace		or	repair.
	Service		load			Keep doors and windows closed.
						Check valves. Replace if necessary.
SYSTEM NOISES	Piping	vibration				Support		piping as required
	Expansion valve hissing					Add	refrigerant.
						Check for plugged liquid line filter drier.
	Compressor noisy					Check valve plates for valve noise.
						Replace compressor (worn bearings).
						Check for loose compressor holddown bolts.
COMPRESSOR LOSES OIL	Leak in system					Repair		leak.
	Mechanical damage (blown piston or					Repair damage or replace compressor.
	broken discharge valve)
	Crankcase heaters not energized					Replace heaters, check wiring and
	durina	shutdown				crankcase heater relay contacts.
FROSTED SUCTION LINE	Expansion valve admitting excess					Check cooler and compressor thermistors.
	refrigerant					Test	EXV.
HOT LIQUID LINE	Shortaae of refriaerant due to leak					Repair leak and recharge
FROSTED LIQUID LINE	Shutoff valve partially closed or restricted					Open valve or remove restriction.
COMPRESSOR DOES NOT	Burned	out coil				Replace		coil
UNLOAD	Defective		capacity control valve			Replace		valve
	Miswired		solenoid			Rewire correctly.
	Weak, broken, or wrong valve body spring					Replace		spring
fgF;RESSOR DOES NOT	Miswired		solenoid			Rewire correctly
	Defective		capacity control valve			Replace		valve.
	Plugged strainer (high side)					Clean or replace strainer.
	Stuck or damaged unloader piston or					Clean or replace the necessary parts.
	piston ring(s)

67