Carrier 30HK - Manual (Page 15)

TROUBLESHOOTING GUIDE (cont)
SYMPTOM 1 PROBABLE CAUSE REMEDY
System noises | Piping vibration 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
holddown bolts.
Freeze-up improper charging Make sure that a full quantity of
water is flowing thru the cooler
while charging and that suction
pressure in cooler is equal to or
greater than that corresponding to
32 F (58 psig for Refrigerant 22).
Improperly set safety thermostat Check safety thermostat for proper
setting at beginning of each
season.
Operating with safety thermostat
bypassed If thermostat was bypassed
for checking, be sure it is back in
the circuit before starting the unit.
Improper circulation of chilled
water
Use ample size cleanable strainer
in the chilled water circuit. Make
sure strainer is clean. It may some­
times be necessary to chemically
treat the water to prevent forma­
tion of deposits.
System not drained for winter
shutdown
Remove drain plugs at end of
cooling season. Blow out any
residual water. Instead of drain­
ing, a suitable antifreeze may be
added to the water. Damage to the
chiller due to freezing is considered
abuse and may affect the warranty.
Hot liquid line Shortage of refrigerant due to leak Repair leak and recharge.
Frosted liquid line Restricted filter drier Remove restriction or replace
filter drier core.
Compressor will not unload Burned-out coil Replace coil.
Defective capacity control valve Replace valve.
Miswired solenoid Rewire correctly.
Weak, broken or wrong valve body
spring Replace spring.
Compressor will not load Miswired solenoid Rewire correctly.
Defective capacity control valve Replace valve.
Plugged strainer (high side) Clean or replace strainer.
Stuck or damaged unloader piston
or piston rings.
Clean or replace necessary parts.
15