CSZ ZP 16, Installation, Operation & Maintenance Manual, Page: 68 / 88

MAINTENANCE WITH Q&A
Page 5-6
GENERAL TROUBLESHOOTING PROCEDURES
Table 4. 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
dif
fi cult 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 measure winding resistance
Defective start relay Check and replace
Low Amps Low refrigerant Check for leaks; charge system
Insuf fi cient
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