Cincinnati Sub-Zero ZP Series - Page 81

MAINTENANCE WITH Q & A
69
GENERAL TROUBLESHOOTING PROCEDURES
PROBLEM
PROBABLE CAUSE
CORRECTIVE ACTION
Compressor will
not run
Conditioning system OFF
Turn ON conditioning system
No electrical power
Check facility circuit breaker
Wrong voltage applied to unit
Check voltage and correct
Compressor internal overload
tripped
Will automatically reset when cooled
High/Low Limit tripped
Correct cause of limit condition, repair and reset
Control alarm energized
Motor failure
Check winding resistance and lead to ground resistance
Motor shorted
Replace compressor
Circuit breaker may be tripped
Refer to section on Resetting a Circuit Breaker
Unit short cycles
continuously
Gain setting too high
Decrease gain setting
Proportional band setting to low
Increase proportional band setting
Compressor low on refrigerant
Check refrigerant and charge if necessary
Compressor
difficult to start
Wrong voltage applied to unit
Connect correct voltage
Defective run/start capacitor(s)
Replace capacitor(s)
Defective start relay
Replace start relay
Refrigeration overcharge
Recover and recharge
High load amps
Low voltage
Check supply circuit
Electrical malfunctions
Check for proper wiring and correct compressor capacitor
Check for grounds and measur
e winding resistance
Defective start relay
Check and replace
Low Amps
Low refrigerant
Check for leaks; charge system
Insufficient
cooling effect
Refrigerant shortage
Repair leak and recharge
Frosted coil
Defrost and dry coil
Low air circulation
Check fan blade and shaft. Blade may have come off
Exceeding rated live load capacity
(See data sheets)
Reduce live load
Cooling coils obstructed
Remove obstruction or defrost
TXV defective
Replace valve
Solenoid coil burned out
Replace coil
Solenoid valve bad
Replace valve
Dirty condenser
Clean condenser
R-404A compressor frosting
Possible leak in R-508B/R-23. Check ambient pressures
R-508B/R-23
Head Pressure
too high
Refrigerant overcharge
Recover excess refrigerant
Exceeding rated live load capacity
(See data sheets)
Reduce live load
Air in system
Recover, evacuate and recharge.
R-404A system short of gas
Repair leak and recharge
Table 5-4: General Troubleshooting Procedures