Emerson Liebert.CRV+ Series User Manual

54 Chapter 8 Troubleshooting
Liebert.CRV+ Series Air Cooled Precision Air Conditioner User Manual
Table 8-3 Troubleshooting of compressor and cooling system
Symptom Possible causes Items to be checked or handling method
Compressor can’t be 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 if there is a HP alarm. Refer to Chapter 5.
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 if contactor is able to energize.
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

Emerson Liebert.CRV+ Series Specifications

General

Brand	Emerson
Model	Liebert.CRV+ Series
Category	Air Conditioner
Language	English