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Operation and Maintenance Instructions
Envistar Top 04-21
DSET.181201.00.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/medium
The power supply has been interrupted
Check the control/safety switches and
fuses
No or too low air flow across evaporator. Check that nothing is blocking the air-
flow.
The thermostat/control equipment is
incorrectly set/defective.
Adjust the settings or replace the
equipment
Compressor is not operating
See symptom “Compressor is not op-
erating”
Compressor is not op-
erating
The power supply has been interrupted
Check the control/safety switches and
fuses
Compressor has opened a safety circuit
Check and reset, if needed
The control unit is switched off
Start the control unit
Compressor defect
Check/replace
Frost on the evaporator
The expansion valve is incorrectly preset/
defective
Check/replace
Insufficient refrigerant volume
Look for leakage, seal the leak and top
up with refrigerant
Low supply 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 the fault must be rectified, after which the control unit’s
“Alarm reset” button must be pressed for at least 2 seconds. If the safety circuit
alarm trips repeatedly, an authorised refrigeration service company must be
engaged.