Fault Finding and Troubleshooting Multi-DENCO
126 FläktGroup DC-2013-0101-GB • Subject to modifications • R5-08/2020
11.2 When the Pressure Relief Valve (PRV) Has Discharged
The pressure relief valve is a safety device to prevent the pressure inside of the direct
expansion circuit from exceeding safety limits. If the device has discharged the refrig-
erant from the system, the following actions MUST be followed:
• The PRV must be replaced
• A fault-finding investigation must be undertaken to find the cause behind the
discharge and all corrective actions undertaken
• Any local legislation or requirements for reporting of refrigerant discharge must be
fulfilled
• F-Gas logbook must be maintained appropriately, as per your local regulations
Unit not cooling/heating/
humidifying/dehumidifying
Airflow failure alarm Check fan operation and suitable clearances in and around
the fan. Check output of the controller to the fan and each
fan relay is energised.
Heater over-temperature alarm
(heating only)
Check the heater thermostat for functionality, replace if nec-
essary and check function of heaters.
Water detection alarm Standard configuration disables the humidifier only. Settings
available in the controller allow for whole unit operation to be
stopped. Inspect underneath the unit for presence of water
and check coil condensate tray.
Sensor failure Certain temperature and pressure sensors, upon failure, will
disable functions of the unit. Refer to the controls manual to
see what function is affected by each sensor.
Low oil level (functions disabled
by compressor alarms)
Check for possible leaks and the recent operations of the
unit (to ensure suitable functionality). Add oil as necessary
and re-commission the unit.
Fault Possible Reason Possible Remedy
Tab. 11-1
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