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RTC 13e - www.regulus.eu
6.4. Diagnostics and possible causes of fault conditions
Fault condition
Possible cause / diagnostics
Insufficient flow rate of hea
-
ting water
Possible causes:
• air in system / low pressure
• dirty filter
• closed valve
• impurities settled in plate heat exchanger
• other obstacles in water flow
• defect circulation pump
• too small pipe diameter
Compressor overcurrent
Check:
• power supply cable and tightening of terminals
• device power consumption
• technical condition of the fan
• clogging of the finned and plate heat exchangers
• heating water temperature and flow and return temperarture
difference
Protection of IPM module
This is a compressor speed control error. Check:
• compressor inverter board
• whether cables aren’t interrupted or loose
• technical condition of the compressor
Compressor lubrication
If the unit is operated at low compressor speed for a long time, the
unit will increase the speed to get more oil into the compressor.
This is a normal condition that does not require any intervention.
High/low refrigerant pres-
sure
Check:
• technical condition of the fan and circulation pump
• filter
• cleanliness of the finned and plate heat exchangers
• heating water temperature and flow and return temp. difference
• refrigerant quantity
Reduction of compressor
speed at high refrigerant
condensation pressure
Check:
• technical condition of the fan and circulation pump
• filter
• cleanliness of the finned and plate heat exchangers
• heating water temperature and flow and return temp. difference
Compressor warm-up
If the compressor has not been running for a long time or if the
outdoor temperature is too low, the compressor heater will switch
on. This is a normal condition that does not require any intervention.
Compressor high outlet
temperature protection
Check:
• whether the water outlet temperature isn’t set too high
(especially at low outdoor temperatures)
• whether the heating water flow isn’t too low
• whether there isn’t too little oil in the compressor
• whether there is sufficient refrigerant in the unit
Finned heat exchanger
temperature sensor protec-
tion
Check:
• that sufficient airflow through the finned heat exchanger is ensured
Undervoltage / overvoltage
of the power supply
Check:
• the value of the power supply voltage
Speed limitation or compre-
ssor shutdown due to high /
low outdoor temperature
This is a normal condition that does not require any intervention.
Reduction of compressor
speed at low refrigerant
condensation pressure
Check:
• whether there is sufficient refrigerant in the unit
• that no refrigerant circuit leaks are present
• technical condition of the fan and circulation pump
• whether the expansion valve is working properly
• whether the heating water temperature isn’t too low
• whether the flow and return temperature difference isn’t too big
