Vertiv Liebert CR012 - Page 61

Liebert CR012 Precision Air Conditioning User Manual
56 Chapter 4 Maintenance & Troubleshooting
Symptom
Possible Causes
Items to be checked or handling method
started
voltage, 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 it on again
Compressor coils shorted and burnt
Check the motor and replace it in case of any defects or
malfunction
The Contactor does not
get closed, and the
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 an HP alarm.
Discharging temperature alarm
Check whether 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 the contactor is able to energize.
Compressor driver faulty
Check the compressor driver
The Contactor does not
get closed, and the
compressor does not
start
The Compressor internal protector is
open
Check whether the compressor coil is an open circuit. In
such a scenario, wait till the coil is cooled following
which it will be restored automatically
The Compressor stops
after running for 3
minutes. Contactor open
Refrigerant leaked, the low-pressure
check is too low or abnormal
Check the suction pressure
Check the circuit of the low-pressure sensor
Calibrate accordingly so that the low-pressure sensor
reader is within ±0.3 bar range of the actual pressure
High pressure protection
Condenser clogged
Clean the condenser
Condenser system does not start
Check the condenser fan for the air-cooled system
Too much refrigerant has been charged
Check whether the sub-cooling degree is too high
Low exhaust pressure
Refrigerant leaked
Locate the leakage point, repair it and add the refrigerant
The Fan speed controller of the outdoor
unit is faulty, while the output voltage
remains 100%, irrespective of the
change in the condensing pressure
If the fan speed controller is found faulty, then it has to
be replaced
The suction and exhaust
pressures do not change
after startup
Either the Compressor is reversed or the
internal air tightness of the compressor
has failed
If the compressor is reversed, exchange any two L lines
of the compressor. If the internal air tightness of the
compressor has 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 the
refrigerant
Air filter too dirty
Replace the air filter
Filter drier clogged
Replace the filter drier
Improper superheating degree
Check the control board of the electronic expansion
valve (EEV)
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
inspect if the condenser is clogged.
Check that the fans of the evaporator and condenser are
normal
Too high suction overheat degree
Regulate the EEV or add proper amount of refrigerant