Page 69
Operation and Maintenance
Envistar Top 04-21
DSET.220501.07.en
Continuous product development may give rise to specification changes without notice.
Troubleshooting via symptoms
Symptom
Possible cause
Corrective action
Low cooling power - too
high temperature in the
cooled object
The power supply has been interrupted
Check the control/safety switches and
fuses.
Separate supply not connected
Connect supply
None or too low air flow across evapora-
tor
Check that nothing inhibits the air flow
The control equipment is incorrectly pre-
set/defective
Adjust the settings or replace the
equipment
Compressor is not ope-
rating
The power supply has been interrupted.
Check the control/safety switches and
fuses
Incorrect phase sequence (compressor 2) Switch two of the incoming phases
Compressor has opened a safety circuit
Check and reset, if needed
Defective compressor
Check/replace
Frost on the evaporator
(heating application)
Expansion valve is defective
Check/replace
Insufficient refrigerant volume
Look for leakage, seal the leak and top
up with refrigerant
Low return air flow
Adjust the flow
Alarm reset
In the event of an alarm initiated by the frequency inverter or the safety circuit,
the compressor stops and the sum alarm relay is energised. The alarm is
displayed in the control unit menus “Operating information, compressors” and
“Status: Alarm”.
In the event of an alarm, take corrective action to correct the fault, and then
press the “Alarm reset” button on the control unit for at least 3 seconds. If the
safety circuit alarm trips repeatedly, an authorised refrigeration service company
must be contacted.