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RTC 13e - www.regulus.eu
Fault condition
Possible cause / diagnostics
Temperature sensor error
Check:
• sensor resistance
• sensor connection and cable
High pressure / low pres-
sure switch error
The error message occurs either if the pressure switch is not closed
in standby mode, or 2 minutes after the compressor is switched off.
Check:
• the connection and the correct function of the pressure switch
Fan error
The fan has not reached the required speed or is not sending
a feedback signal.
Check:
• fan PCB
• fan motor
• cables
Refrigerant evaporation
pressure too low
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
Refrigerant condensation
pressure too high
Check:
• whether there isn’t too much refrigerant in the unit
• whether the water flow is sufficient
• filter
• technical condition of the fan and circulation pump
• whether the expansion valve is working properly
• whether the heating water temperature isn’t too high
• whether the flow and return temperature difference isn’t too large
• whether the heat exchangers heat transfer surfaces are not clogged
Communication error
Check:
• cables
• settings of switches on the PCB (see chap. 4.7. Addressing HPs
in cascade)
Compressor phase error
(current or overload)
Check:
• compressor power cable
• the inverter board and its connections
Undervoltage / overvoltage
of the VDC module
Input voltage is too high or low.
EEPROM error
Turn off the power and use a jumper to connect the JP404 termi
-
nals on the outdoor unit PCB. Turn on the power. Turn off the power
and remove the jumper on the JP404 terminals. If the error persists,
replace the PCB.
The outgoing water tempe-
rature is too low
If the outgoing water temperature in cooling mode is lower than
5 °C, the compressor will switch off.
Check:
• temperature sensor
• water temperature
• water flow rate
The outgoing water tempe-
rature is too high
If the outgoing water temperature in heating mode is higher than
58 °C, the compressor will switch off.
Check:
• temperature sensor
• water temperature
• water flow rate
Defrost error
Check:
• water temperature
Water temperature too low
in heating or DHW mode
If the water temperature is lower than 15 °C, the compressor will switch
off. The compressor switches on when the flow temperature exceeds
17 °C. This is a protection that prevents damage to the compressor.
