Alarms

The alarm indicates that the system has detected an issue that requires attention. Begin by following the recommended actions displayed on the screen.

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#

Friendly name

Trigger

Possible cause

Product action

Service action

1

Outdoor Sensor Error (BT1)

Temperature outside allowed range (outdoor temperature sensor, BT1).

The temperature sensor does not work or has a bad connection.

  • Manual reset required.

  • Check connections.

  • If needed, replace the sensor.

2

Indoor Sensor Error (BT2)

Temperature outside allowed range (indoor temperature sensor, BT2).

The temperature sensor does not work or has a bad connection.

  • Manual reset required.

  • Block indoor curve compensation.

  • Check connections.

  • If needed, replace the sensor.

3

Pool Sensor Error (BT4)

Temperature outside allowed range (pool temperature sensor, BT4).

The temperature sensor does not work or has a bad connection.

  • Manual reset required.

  • Check connections.

  • If needed, replace the sensor.

4

Flow Line Sensor Error (BT11)

Temperature outside allowed range (supply temperature sensor, BT11).

The temperature sensor does not work or has a bad connection.

  • Manual reset required.

  • Switch to manual mode.

  • Block distribution system heating.

  • Check connections.

  • If needed, replace the sensor.

5

External Flow Line Sensor Error (BT12)

Temperature outside allowed range (external supply temperature sensor, BT12).

The temperature sensor does not work, is missing, or has a bad connection.

  • Manual reset required.

  • Check connections.

  • If needed, replace the sensor.

6

Tank Temperature Sensor Error (BT30)

Temperature outside allowed range (DHW tank temperature sensor, BT30).

The temperature sensor does not work or has a bad connection.

  • Manual reset required.

  • Block DHW circulation pump (GP2).

  • Block DHW production.

  • Block mixing valve (QN8).

  • Switch to manual mode.

  • Check connections.

  • If needed, replace the sensor.

7

Heating Medium PHEX Inlet Sensor Error (BT31)

Temperature outside allowed range (heating medium PHEX inlet sensor, BT31).

The temperature sensor does not work or has a bad connection.

  • Manual reset required.

  • Block DHW circulation pump (GP2).

  • Check connections.

  • If needed, replace the sensor.

9

Hot Water PHEX Outlet Sensor Error (BT34)

Temperature outside allowed range (hot water PHEX outlet temperature sensor, BT34).

The temperature sensor does not work or has a bad connection.

  • Auto-reset.

  • Block DHW circulation pump (GP2).

  • Check connections.

  • If needed, replace the sensor.

10

Auxiliary Input Error (BTX)

Invalid input on auxiliary input (BTX).

The auxiliary temperature input is faulty or has a bad connection.

  • Auto-reset.

  • Block pool heating.

  • Check input signal.

  • If needed, replace the sensor.

11

Condenser Outlet Sensor Error (BT10)

Temperature outside allowed range (condenser outlet temperature sensor, BT10).

The temperature sensor does not work, is missing, or has a bad connection.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check connections.

  • If needed, replace the sensor.

13

Source Flow Sensor Error (BT14)

Temperature outside allowed range (source inlet temperature sensor, BT14).

The temperature sensor does not work or has a bad connection.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check connections.

  • If needed, replace the sensor.

14

Source Return Flow Sensor Error (BT15)

Temperature outside allowed range (source outlet temperature sensor, BT15).

The temperature sensor does not work or has a bad connection.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check connections.

  • If needed, replace the sensor.

15

Sink Flow Sensor Error (BT20)

Temperature outside allowed range (discharge line temperature sensor, BT20).

The temperature sensor does not work or has a bad connection.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check connections.

  • If needed, replace the sensor.

19

Suction Line Sensor Error (BT23)

Temperature outside allowed range (suction line temperature sensor, BT23).

The temperature sensor does not work or has a bad connection.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check connections.

  • If needed, replace the sensor.

21

Low Pressure Transmitter Error (BP1)

Pressure outside allowed range (low‑pressure transmitter, BP1).

The low‑pressure transmitter (BP1) does not work or has a bad connection.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check connections.

  • If needed, replace the sensor.

22

High Pressure Transmitter Error (BP2)

Pressure outside allowed range (high‑pressure transmitter, BP2).

The high‑pressure transmitter (BP2) does not work or has a bad connection.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check connections.

  • If needed, replace the sensor.

27

Com EA2W Module Error

Communication lost with compressor module.
  • Software issue.
  • Failed update.
  • Faulty communication wiring.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Block DHW circulation pump (GP2).

Check the communication cable and connections between the main board and the fan control board.

29

Inverter Error 5× in 3 hours

Inverter fault occurred five times within three hours.

  • Insufficient flow.

  • Wiring fault on inverter.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check flow.

  • Check power supply.

30

Filter Change Alarm

Filter change interval elapsed.

The exhaust air filters are dirty or worn out.

  • Manual reset required.

Replace the filters.

31

Hot Gas Alarm

Discharge temperature envelope exceeded (discharge temperature sensor, BT20).

  • Compressor malfunction.

  • Refrigerant leakage.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

Replace the compressor unit.

33

High Pressure Alarm

Pressure envelope exceeded (high‑pressure transmitter, BP2).

Insufficient flow.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check function of circulation pump.

  • Ensure sufficient flow in heating system.

35

Low Pressure Alarm

Pressure envelope exceeded (low‑pressure transmitter, BP1).

  • Refrigerant leakage.

  • Insufficient exhaust-air flow.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.
  • Check fan and filters for correct flow.

  • Replace the compressor unit.

37

Source Temperature Alarm

Compressor stopped due to low source temperature (BT15) repeatedly.
  • Too low source medium temperature.

  • Insufficient source medium flow.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Close damper for outdoor air mix.

  • Increase fan speed.

39

EEV Actuator Malfunction

Superheat out of range (electronic expansion valve, QN1) occurred repeatedly.

  • Refrigerant leakage.

  • EEV actuator fault.

  • Faulty suction line temperature sensor (BT23).

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check for refrigerant leakage.

  • Replace the EEV actuator.

  • Replace the BT23 temperature sensor.

42

BT23 Low Temperature Alarm

Low suction line temperature (BT23).

  • Refrigerant leakage.

  • EEV actuator fault.

  • Faulty suction line temperature sensor (BT23).

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check for refrigerant leakage.

  • Replace the EEV actuator.

  • Replace the BT23 temperature sensor.

43

No Communication With Outdoor Module

Communication lost with heat pump.
  • No power supply to heat pump.
  • Faulty communication.
  • Start-up sequence error.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

Check the communication cable and connections.

44

Low Defrost Flow

Defrost attempt failed occurred repeatedly.

  • Insufficient flow over the condenser.

  • Faulty flow switch.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check function of circulation pump.

  • Check function of flow switch.

  • Ensure sufficient flow in heating system.

45

Fan Error (No RPM Feedback)

Fan speed signal fault occurred repeatedly.

  • Fan hardware fault.

  • Faulty wiring between fan and control board.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

  • Check wiring from fan.

  • Check connection on fan board.

47

Incompatible Software in the Outdoor Module

Obsolete or incompatible software detected in outdoor module.

Heat pump software version not compatible with controller.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

Update software on heat pump.

53

Cooling blocked – Low ambient temperature

Outdoor air temperature too low for cooling operation.

Cooling is requested at a too low outdoor-air temperature.

Auto-reset.

 –

60

Anti-freeze protection

Anti-freeze protection triggered.

Low temperature in system circuit.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

Force immersion heater operation until the temperature increases.

61

Low water flow protection

Low water flow protection triggered.

Insufficient water flow in the distribution system.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Clean filters.

  • Increase pump speed.

  • Open the thermostats.

64

Exhaust temperature overprotection

High exhaust temperature (BT20).

  • Compressor malfunction.

  • Refrigerant leakage.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check for refrigerant leakage.

  • Check function of compressor.

69

High flow temperature difference protection

High deltaT over condenser.

Insufficient flow over the condenser.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Clean filters.

  • Increase pump speed.

  • Open the thermostats.

70

Outlet water over heat

High outlet water temperature (BT10).

Insufficient flow over the condenser.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Clean filters.

  • Increase pump speed.

  • Open the thermostats.

84

High pressure protection 3 times

Pressure above maximum operating limit occurred three times within thirty minutes.

Insufficient flow over the condenser.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Clean filters.

  • Increase pump speed.

  • Open the thermostats.

86

Low pressure protection 3 times

Pressure below minimum operating limit occurred three times within thirty minutes.
  • Faulty defrosting.

  • Refrigerant leakage.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check for refrigerant leakage.

  • Check function of compressor.

90

Low water flow protection 3+

Low water flow protection occurred three times within one hour.

Insufficient water flow in the distribution system.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Clean filters.

  • Increase pump speed.

  • Open the thermostats.

92

Anti-freeze protection 3 times

Anti-freeze protection occurred three times.

Low temperature in system circuit.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

Force immersion heater operation until the temperature increases.

96

Discharge over heat protection 3 times

High exhaust temperature (BT20) occurred three times within thirty minutes.

  • Compressor malfunction.

  • Refrigerant leakage.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check for refrigerant leakage.

  • Check function of compressor.

98

High flow temperature difference protection 3 times

High deltaT over condenser occurred three times within thirty minutes.

Insufficient water flow.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Clean filters.

    Increase pump speed.

  • Open the thermostats.

99

Low outlet water temp 3 times

Low outlet water temperature (BT10) occurred three times within thirty minutes.

  • Insufficient water flow.

  • Incorrect configuration.

  • Thermostats not open.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Clean filters.

  • Check function of circulation pump.

  • Open the thermostats.

100

Outlet water overtemperature protection 3 times

High outlet water temperature (BT10) occurred three times within thirty minutes.

Insufficient flow over the condenser.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Clean filters.

  • Increase pump speed.

  • Open the thermostats.

112

Inlet water temperature failure

Temperature outside allowed range (heating return temperature sensor, BT13).

The temperature sensor does not work or has a bad connection.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

  • DHW control without condenser inlet sensor (BT13).

  • Check connections.

  • If needed, replace the sensor.

113

Outlet water temperature failure

Temperature outside allowed range (outlet water temperature sensor, BT10).

The temperature sensor does not work or has a bad connection.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

  • Check connections.

  • If needed, replace the sensor.

114

Coil temperature failure

Temperature outside allowed range (evaporator outlet temperature sensor, BT25).

The temperature sensor does not work or has a bad connection.

Auto-reset.

  • Check connections.

  • If needed, replace the sensor.

115

Ambient temperature failure

Temperature outside allowed range (ambient temperature sensor, BT14).

The temperature sensor does not work or has a bad connection.

Auto-reset.

  • Check connections.

  • If needed, replace the sensor.

116

Suction temperature failure

Temperature outside allowed range (suction line temperature sensor, BT23).

The temperature sensor does not work or has a bad connection.

Auto-reset.

  • Check connections.

  • If needed, replace the sensor.

123

Discharge temperature failure

Temperature outside allowed range (exhaust temperature sensor, BT20).

The temperature sensor does not work or has a bad connection.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

  • Check connections.

  • If needed, replace the sensor.

126

Low ambient temperature failure

Low ambient temperature.
  • The ambient temperature is too low.
  • The ambient temperature sensor has excessive deviation.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

Protect heat pump and pipework from freezing.

127

Low outlet water temperature

Low outlet water temperature (BT10).

  • Insufficient water flow.

  • Incorrect configuration.

  • Thermostats not open.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

  • Clean filters.

  • Check function of circulation pump.

  • Open the thermostats.

139

Fan 1 failure

Fan failure on heat pump.
  • Faulty parameter settings.
  • Faulty connection.
  • Fan communication fault.
  • Malfunctioning fan module.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

  • Check fan wiring and connections.

  • Replace the fan.

140

Fan 2 failure

Fan failure (secondary fan) on heat pump.

Communication failure between main board and fan motor module board.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

  • Check fan wiring and connections.

  • Replace the fan.

141

Communication failure (mainboard with fan motor module board)

Communication fault between main board and fan motor module.

  • Faulty connection or poor contact.

  • Damaged communication wiring or port.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

  • Check fan wiring and connections.

  • If needed, replace the fan control board.

143

Communication failure (mainboard with fan motor 2 module board)

Communication fault between main board and secondary fan motor module

  • Faulty connection or poor contact.

  • Damaged communication wiring or port.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

Check fan wiring and connections.

144

IPM overheat

High inverter temperature.
  • Fan not rotating and high current.
  • Insufficient thermal coupling.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

Check fan function.

145

Compressor start failure

Drive fault on the compressor.

  • Incorrect compressor model code.

  • Faulty wiring or damaged inverter board.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

  • Check compressor wiring.

  • Replace the inverter board.

146

Compressor over current

Compressor current too high.

Damaged current detection circuit.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

Measure current to compressor.

147

Input voltage phase loss

Input voltage phase loss detected.
  • Incorrect power supply connection.
  • Damaged fuse or inverter drive.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

Check incoming power supply.

148

IPM current sampling fault

Incorrect AC current measurement.
  • Excessive phase imbalance in the inverter.

  • Damaged inverter board.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

  • Check power supply.

  • Replace the inverter.

149

Overheat protection of drive board devices

Overheat protection for drive board devices.
  • Fan not running.
  • Poor thermal coupling.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

Check fan function.

150

Pre‑charge failure

Pre‑charge failure.
  • Input phase loss.
  • Power cycling without full discharge.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

Measure incoming power supply.

151

DC bus overvoltage

DC bus voltage above permitted limit.
  • Input voltage too high.

  • Damaged sampling circuit.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

Measure incoming power supply.

152

DC bus undervoltage

DC bus voltage below permitted limit.
  • Input voltage too low.

  • Damaged sampling circuit.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

Measure incoming power supply.

153

AC input voltage undervoltage

Input voltage too low.

Grid voltage below permitted operating range.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

Measure incoming power supply.

154

AC input overcurrent shutdown

High input current.

Damaged current sampling circuit.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

Measure incoming power supply.

155

Input voltage sampling fault

Incoming power supply outside expected range.

  • Abnormal input voltage.

  • Damaged voltage sampling circuit.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

Measure incoming power supply.

156

DSP and PFC communication failure

Communication fault between DSP and PFC.

Damaged driver board or control electronics.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

Replace the driver board.

157

Drive plate temperature fault

Temperature outside allowed range (driver board).

Damaged sensor or inverter board.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

Replace the inverter board.

158

DSP and communication board communication failure

Communication fault between DSP and communication board.

Damaged driver board.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

Replace the driver board.

159

Mainboard communication failure

Mainboard communication failure detected.
  • Damaged communication wiring.
  • Damaged controller board.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

  • Check wiring.

  • Replace the controller board.

161

Compressor default phase

Compressor phase loss.
  • Incorrect wiring.
  • Damaged compressor.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

Measure incoming power supply.

163

Faulty input current sampling

Incorrect input current measurement.
  • Damaged switched‑mode power supply.

  • Damaged inverter board.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

  • Measure incoming power supply.

  • Replace the inverter board.

166

EEPROM fault

Invalid EEPROM data.
  • Corrupted EEPROM data.

  • Damaged inverter board.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

Replace the inverter board.

167

Input voltage overlimiting protection

AC input voltage above maximum operating limit.
  • Grid overvoltage.

  • Damaged voltage sampling circuit.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

Measure incoming power supply.

175

Compressor overspeed protection

Compressor speed too high.

  • Incorrect compressor model code.

  • Damaged inverter board.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

Replace the inverter board.

247

Return water temperature sensor fault

Temperature outside allowed range (condenser inlet temperature sensor, BT13).

The temperature sensor does not work or has a bad connection.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

  • Check connections.

    If needed, replace the sensor.

248

Outlet water temperature sensor fault

Temperature outside allowed range (condenser outlet temperature sensor, BT10).

The temperature sensor does not work or has a bad connection.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

  • Check connections.

    If needed, replace the sensor.

253

Fault of water inlet sensor at water source side

Temperature outside allowed range (source inlet temperature sensor, BT14).

The temperature sensor does not work or has a bad connection.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

  • Check connections.

    If needed, replace the sensor.

254

Fault of water outlet temperature sensor at water source side

Temperature outside allowed range (source outlet temperature sensor, BT15).

The temperature sensor does not work or has a bad connection.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

  • Check connections.

    If needed, replace the sensor.

256

Exhaust temperature sensor fault

Temperature outside allowed range (discharge line temperature sensor, BT20).

The temperature sensor does not work or has a bad connection.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

  • Check connections.

  • If needed, replace the sensor.

257

Suction air temperature sensor fault

Temperature outside allowed range (suction line temperature sensor, BT23).

The temperature sensor does not work or has a bad connection.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

  • Check connections.

  • If needed, replace the sensor.

269

Main Control-Press Driver Communication Failure

Communication lost between inverter driver chip and controller chip.
  • No software.
  • Damaged inverter driver chip.
  • Damaged hardware circuit between the inverter driver chip and controller chip.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

  • Check power supply.

  • Replace the compressor unit.

274

Driver DC bus over-voltage and under-voltage protection

DC bus voltage is outside compressor voltage envelope.

 Internal inverter fault (hardware).

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

  • Check power supply.

  • Replace the compressor unit.

275

Low pressure sensor failure

Pressure outside allowed range (low pressure sensor, BP1).

The pressure sensor (BP1) does not work or has a bad connection.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

Replace the compressor unit.

276

High pressure sensor fault

Pressure outside allowed range (high pressure sensor, BP2).

The pressure sensor (BP2) does not work or has a bad connection.

  • Auto-reset.

  • Block compressor.

  • Force immersion heater operation.

Replace the compressor unit.

279

Fault of water flow switch on the ground source side.

QG: Low flow at the GP4 source medium pump.

QG-C: Low flow at the BF2 flow sensor.

Insufficient source medium flow.

Auto-reset.

Check source medium flow.

306

Driver module protection (FO)

Inverter driver module protection triggered occurred three times within one hour.

  • Compressor malfunction.

  • Internal inverter fault.

  • Faulty compressor wiring.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check power supply.

  • Replace the compressor unit.

307

Compressor out of step/or start failure/phase loss

Compressor unable to start occurred three times within one hour.

The compressor is out of step or has a phase loss despite restart attempts.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check power supply.

  • Replace the compressor unit.

308

Driver input overcurrent protection/phase current overcurrent protection/current detection circuit fault

High input current occurred three times within one hour.

The current exceeds the maximum allowed current despite restart attempts.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check power supply.

  • Replace the compressor unit.

309

Driver module hardware protection/IPM module temperature sensor fault

Inverter temperature signal unavailable occurred three times within one hour.

The IPM sensor does not work or has a bad connection.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check power supply.

  • Replace the compressor unit.

310

Low pressure switch off protection (Low low pressure protection)

Low pressure at the low‑pressure sensor (BP1) occured three compressor within one hour.

  • Insufficient source medium flow.

  • Fault on expansion valve.

  • Refrigerant leakage.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check source medium flow.

  • Replace the compressor unit.

311

High pressure switch off protection

High pressure switch open occurred three times within one hour.

  • Insufficient water flow.

  • Compressor malfunction.

  • High pressure switch is faulty or has a poor connection.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check system flow.

  • Replace the compressor unit.

312

Excessive exhaust temperature protection

High discharge line temperature (BT20) occurred three times within one hour.

Compressor malfunction.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check power supply.

  • Replace the compressor unit.

313

Driver IPM overtemperature protection

High inverter board temperature occurred six times within one hour.

  • Compressor malfunction.

  • Internal inverter fault.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check power supply.

  • Replace the compressor unit.

315

Over-pressure protection of high pressure

High pressure at the high‑pressure sensor (BP2) occured three times within one hour.

  • Insufficient water flow.

  • Compressor malfunction.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check system flow.

  • Replace the compressor unit.

325

Low-pressure protection for high-pressure

Low pressure at the high‑pressure sensor (BP2) occured three times within one hour.

Compressor envelope constraints.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check system flow.

  • Check system temperature.

  • Check source medium flow.

  • Check source medium temperature.

326

High-pressure protection for low-pressure

High pressure at the low‑pressure sensor (BP1) occured three times within one hour.

Compressor envelope constraints.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Check system flow.

  • Check system temperature.

  • Check source medium flow.

  • Check source medium temperature.

327

Fault of water flow switch on the ground source side

QG: Low flow at the GP4 source medium pump occurred three times within one hour.

QG-C: Low flow at the BF2 flow sensor occurred three times within one hour.

Insufficient source medium flow.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

Check source medium flow.

333

Com W2W Module 1 Error

Communication lost with compressor module EP10.

  • Wiring issue.

  • Inverter PCB fault.

  • Broken fuse on main board.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Block DHW circulation pump (GP2).

  • Check power supply.

  • Check communication cable and connections between compressor unit and main board.

334

Com W2W Module 2 Error

Communication lost with compressor module EP11.

  • Wiring issue.

  • Inverter PCB fault.

  • Broken fuse on main board.

  • Manual reset required.

  • Block compressor.

  • Force immersion heater operation.

  • Block DHW circulation pump (GP2).

  • Check power supply.

  • Check communication cable and connections between compressor unit and main board.