Carrier 30H - Manual (Page 14)

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