Carrier 30HK - Manual (Page 14)

TROUBLESHOOTING GUIDE
SYMPTOMS 1
PROBABLE CAUSE REMEDY
Compressor does not run ! Power line open Reset circuit breaker.
!
Control circuit breaker tripped Check control circuit for ground or
short.
s
Reset breaker.
j Safety tripped Reset.
1
Tripped power breaker Check the controls. Find cause of
trip and reset breaker.
Condenser circulating pump not Power off — restart.
running
Pump binding — free pump.
1
j
Incorrect wiring — rewire.
Pump motor burned out — replace.
Loose terminal connection Check connections.
Improperly wired controls Check wiring and rewire.
1
Low line voltage Check line voltage — determine
location of voltage drop and
remedy deficiency.
j
Compressor motor defective Check motor winding for open or
short. Replace compressor, if
necessary.
;
i
Seized compressor Replace compressor.
Compressor cycles on low-
i
Low-pressure control erratic in Raise differential setting.
pressure control action
Check capillary for pinches.
1 Replace control.
Compressor suction valve leaking Replace valve plate.
Compressor suction shutoff valve
partially closed Open valve.
Low refrigerant charge Add refrigerant.
Plugged compressor suction
strainer
Clean strainer or replace.
Compressor loses oil Leak in system Repair leak.
Mechanical damage (blown piston
or broken discharge valve)
Repair damage or replace
compressor.
Oil trapped in line Check piping for oil traps.
Crankcase heaters not energized
during shutdown Check wiring and crankcase
heater relay. Replace heater if
necessary.
Frosted suction line Expansion valve admitting excess
refrigerant Adjust expansion valve. Replace
valve if defective.
Compressor cycles on high- High-pressure control erratic in Check capillary tube for pinches.
pressure control action
Set control as required.
Compressor discharge valve
partially closed Open valve, or replace if defective.
Air in system Purge.
Condenser scaled Clean condenser.
Condenser water pump or fans not
operating Start pump — repair or replace if
defective.
Unit operates long or Low refrigerant charge Add refrigerant.
continuously
Control contacts fused Replace control.
Air in system Purge.
Partially plugged or plugged
expansion valve or strainer
Clean or replace.
Defective insulation Replace or repair.
Service load too high Keep doors and windows closed.
Inefficient compressor Check valves, replace if necessary.
!4