Vertiv Liebert PEX4 Series User Manual

Vertiv | Liebert PEX4 | User Manual 82
Troubleshooting
Symptom Potential Causes Items to be Checked or Handling Process
High- pressure
protection
Low exhaust
pressure
Ball valves do not open
Check, if all ball valves in the refrigeration system are opening properly.
Condenser coils gets
dirty or clogged (air
cooled)
Clean the condenser or plate heat exchanger.
Inlet water temperature
is too high or water
ow is too small (water
cooled)
Check the water quality (Water-cooled system).
Condensing system
does not operate
• Check the condenser fan (air-cooled system).
• Check the water quality (water-cooled system).
Excessive amount of
refrigerant charge
Check whether supercooling is too high.
High pressure switch
fault
• Check if the two terminals of high pressure switch is shorted.
• Check the resistance between J18-3 and terminal G for HP switch
#1 and J20-1 and G for HP switch #2.
Compressor contactor
fault or compressor
delay fault
• Manually open compressor through service tool, if there is 24 Vdc
between contactor A1 & A2, while the contactor does not actuate,
then replace the contactor.
• If there is no 24 Vdc between A1 and A2, then check whether there
is 24 Vdc between J18-3 (system #1) or J20-1 (system #2) and
terminal G. If there is, then replace the compressor delay.
Electric valve
improperly adjusted
(water-cooled)
• Check if the dierentiation between high pressure sensor
readings and actual values are within ± 0.6 bar (high and low pres-
sure sensors values can be read in service tool, shown as gauge
pressure).
• Check whether the electric ball valve of the plate heat exchanger
functions well.
Low discharge
pressure
Excessive ow or low
water temperature
(water cooled)
Check water supply system.
Refrigerant leakage
Check if there is any leakage, if identied repair immediately the
leakage area and add refrigerant.
Outdoor fan speed
controller failure,
leading to running at
full speed and do not
change along with high
pressure
• Check if the high pressure sensor of condenser fails.
• If condenser controller fault is conrmed, replace the speed
controller immediately.
After starting,
suction and
discharge
pressure
unchanged
The compressor
running reversely
or
Suction and discharge
connected
• If it runs reversely, replace any two compressor L line
(inverter output).
• If another reason, then replace the compressor.

Vertiv Liebert PEX4 Series Specifications

General

Brand	Vertiv
Model	Liebert PEX4 Series
Category	Air Conditioner
Language	English