Liebert CRV+ Series User Manual

50 Chapter 7 Troubleshooting
Liebert CRV+ Series Air Conditioner User Manual
Table 7-3 Troubleshooting of compressor and cooling system
Symptom Possible causes Items to be checked or handling method
Compressor does
not start
Not power on (shutdown)
Check the main power against undervoltage,
overvoltage and phase loss
MCB and contactor faulty
Check the compressor MCB, contactor and connecting
cables
Alarm lock
View the unit alarm records, replace the damaged
component and power on it again
Compressor coils shorted and burnt Check the motor and replace it if defects are found
Contactor does not
closed, and
compressor does
not start
Low discharging overheat degree alarm Check the state of the micro-processing controller
High pressure MCB action
Check the high pressure MCB against high pressure
alarm
Discharging temperature alarm Check if a discharging low/high temperature alarm exists
Low pressure alarm View if a low pressure alarm exists in the history alarm
Contactor faulty Check the contactor
Compressor driver faulty Check the compressor driver
Compressor internal protector is open
Check if the compressor coil is open circuit. If so, wait till
the coil is cooled and it will be restored automatically
Compressor stops
after running for
3min. Contactor
open
Refrigerant leaked, the low pressure check is
too low or abnormal
1. Check the suction pressure;
2. Check the circuit of the low pressure sensor;
3. Calibrate that the low pressure sensor reader is within
±0.3bar range of the actual pressure
High pressure
protection
Condenser clogged Clean the condenser
Condenser system does not start Check the condensing fan for air-cooled system
Too much refrigerant has been charged Check whether the subcooling degree is too high
Low exhaust
pressure
Refrigerant leaked Locate the leakage point, repair it and add refrigerant
Fan speed controller of outdoor unit is faulty,
while the output voltage remains 100%,
regardless of the change of condensing
pressure
If the fan speed controller is found faulty, replace it
The suction and
exhaust pressures
do not change after
startup
Compressor reversed or compressor internal
air tightness failed
If compressor is reversed, exchange any two L lines of
the compressor. If the compressor internal air tightness
is failed and cannot be restored, replace the compressor
Low suction
pressure or liquid
returned
Insufficient refrigerant in the system
Check for leaks. Seal the leaking point and add
refrigerant
Air filter too dirty Replace the air filter
Filter drier clogged Replace the filter drier
Improper superheating degree Check the control board of electronic expansion valve
Sensing element of the electronic expansion
valve faulty
Replace the sensing element
Improper air flow distribution Check the air supply and return system
Low condensing pressure Check whether the condenser is faulty
Compressor too
noisy
Liquid returned
Refer to the handling methods of ‘Low suction pressure
or liquid returned’
Bearing worn out due to lubricant loss Add lubricant
Compressor
over-temperature
Too high compression ratio
Check the settings of the HP switch and LP switch, and
make sure whether the condenser is clogged.
Check that the fans of the evaporator and condenser are
normal
Too high suction overheat degree
Regulate the electronic expansion valve or add proper
amount of refrigerant
Note:
Judging the above symptoms is based on refrigerating command

Liebert CRV+ Series Specifications

General

Refrigerant	R410A
Frequency	50/60 Hz
Operating Ambient Temperature	64° to 113°F (18° to 45°C)
Sound Pressure Level	Varies by model (typically 45 dB(A) to 65 dB(A))
Dimensions	Varies by model (consult specific model documentation)
Weight	Varies by model (consult specific model documentation)