Carrier 30HH - Manual (Page 47)

MAINTENANCE
30HH,HJ
/’■'i
SYMPTOMS CAUSE REMEDY
C . Compressor cycles on
high pressure control
(continued)
Condenser scaled Clean condenser
Receiver not properly vented
- refrigerant backs up into
evap, condenser
Repipe as required
Condenser water pump not
operating
Start pump
D. Unit operates long
or continuously
Low refrigerant charge Add refrigerant
Control contacts fused Replace control
Air in system Purge
Partially plugged or plugged ex­
pansion valve or strainer
Clean or replace
Defective insulation Replace or repair
Service load Keep doors and windows closed
Inefficient compressor Check valves
E . System Noises Piping V ibration Support piping as required
Check for loose pipe connectors
Expansion valve hissing Add refrigerant
Check for plugged liquid line
strainer
Compressor noisy Check valve plates for valve
noise
Replace compressor
(worn bearings)
Check for loose compressor
hold down bolts
F. Compressor loses
oil
Leak in system Repair leak
Plugged or stuck compressor
snifter valve
Repair or replace
Oil trapping in line Check piping for oil traps
Crankcase heaters not
energized during shutdown
Replace heaters
G, Frosted or sweating
suction line
Expansion valve admitting
excess refrigerant
Adjust expansion valve
H . Hot liquid line Shortage of refrigerant Repair leak and recharge
Expansion valve opens too
wide
Adjust expansion valve
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