A reference for the protection (P) and error (E) codes shown on the AXEN controller. Tap a code to see what it means, likely causes, and how to diagnose and fix it.
Reset the protection by turning the unit OFF and back ON. If this is not successful, contact your local dealer.
P-codes — Protection & Operational Faults14
P01Water Flow Failure
Manual restart needed
The water flow switch on port TS1 of the hydraulic module PCB opened due to insufficient water flow rate. After 3 occurrences within 30 minutes, a manual power-off restart is required.
Possible causes
- Water flow switch wiring is loose or open
- Water flow rate is too low (check valves, filters, air in system)
- Water flow switch is damaged
- Water pump is damaged
- Hydraulic module PCB is damaged
How to diagnose
- Check whether the valve of water replenishing is off
- Check whether the water flow switch is damaged
- Check whether the Y-shape filter is blocked
Solution
- Open the valve
- Replace the water flow switch
- Clean or replace the filter net
P02High Refrigerant Pressure
Auto-reset
The high-pressure switch HP1 on the discharge pipe opened because discharge pressure rose above 4.5 MPa. Resets automatically when pressure drops below 3.5 MPa.
Possible causes
- Pressure switch HP not connected properly or malfunctioned
- Too much refrigerant charged in the system
- Non-condensable gas (air or nitrogen) in the refrigerant system
- Blockage on the high-pressure side of the refrigerant circuit
- Poor heat transfer on the high-pressure side heat exchanger
- Refrigerant system PCB is damaged
How to diagnose
- Check whether there is water shortage or insufficient pump flow
- Check whether the high pressure switch is damaged
- Check whether the refrigerant system is blocked
- Check whether there is EXV reset sound when the unit is on standby or powered on/off
Solution
- Refill water or add an additional water pump
- Replace the high pressure switch
- Clean the filter of the refrigerant system
- Replace the EXV
P03Low Refrigerant Pressure
Manual restart needed
The suction pressure sensor LPS detected pressure below 0.14 MPa for 10 seconds. Resets when pressure rises above 0.30 MPa. After 3 occurrences within 1 hour, manual restart required.
Possible causes
- Refrigerant leak — system is undercharged
- Blockage on the low-pressure side
- Poor heat transfer on the low-pressure side heat exchanger
- Insufficient water flow rate (cooling mode)
- Low pressure sensor LPS is faulty
- Refrigerant system PCB is damaged
How to diagnose
- Check whether the refrigerant system is leaking
- Check whether the filter in the refrigerant system is blocked
- Check whether the outdoor ambient and inlet water temperature is normal
Solution
- Repair the leakage point
- Replace the filter of the refrigerant system
- If the ambient or water temperature is too high or low the unit will stop — this is normal
P04Coil Overheating (Cooling Mode Only)
Auto-reset
Sensor T3 on the air-side heat exchanger refrigerant outlet detected >65 °C for over 1 minute. Cooling mode only. Resets when T3 drops below 52 °C.
Possible causes
- Temperature sensor T3 connection is loose
- Temperature sensor T3 is short-circuited or faulty
- Poor heat transfer on the air-side heat exchanger (dirty fins or blocked airflow)
- Fan blade or fan motor blocked or damaged
- Refrigerant system PCB is damaged
How to diagnose
- Check whether there is any obstacle preventing the airflow
- Check whether the condenser is too dirty
- Check whether the condenser pipe temperature sensor T3 is normal
Solution
- Clean the vents
- Clean the condenser
- Replace the temperature sensor
P05High Discharge Temperature
Auto-reset
Discharge temperature sensor TP detected overtemperature (>115 °C when ambient <−15 °C; >110 °C otherwise) for more than 30 seconds. Restarts after 10 minutes when TP drops below 90 °C.
Possible causes
- Sensors TP, TA, or TW are loose, short-circuited, or faulty
- High-pressure switch HP1 connection is loose or faulty
- Poor heat transfer on air- or water-side heat exchangers
- High-pressure side blockage (crushed pipe, stuck EEV)
- Insufficient water flow in cooling mode
- Hydraulic module PCB is damaged
How to diagnose
- Check whether the refrigerant system is leaking
- Check whether the discharge temperature sensor is normal
Solution
- Repair the leakage point
- Replace the temperature sensor
P06Outlet Water Temperature Too Low (Cooling Mode Only)
Auto-reset
Sensor TB measured below 4 °C for 120 seconds. Cooling mode only. Resets when TB rises above 8 °C for 1 minute.
Possible causes
- Temperature sensor TB is not connected properly
- Temperature sensor TB is short-circuited or malfunctioned
- Hydraulic module PCB is damaged
How to diagnose
- Check whether there is air in the water circuit system
- Check whether the heat exchanger is blocked
- Check whether the Y-shape filter is blocked
- Check whether the water circuit system is reasonable
Solution
- If there is a problem with the drain valve, replace it
- Blow the plate heat exchanger with water or high-pressure gas in the opposite direction for cleaning
- Clean the filter
- The water circulation system must have a shunt
P07Refrigerant Liquid Temp Too Low (Cooling Mode Only)
Auto-reset
Sensor T5 on the EEV outlet pipe detected <2 °C for 120 seconds. Cooling mode only. Resets when T5 rises above 8 °C for 10 minutes.
Possible causes
- Temperature sensor T5 is not connected properly
- Temperature sensor T5 is short-circuited or malfunctioned
- Refrigerant system PCB is damaged
How to diagnose
- Check for leaks in the system
- Check whether the Y-shape filter is blocked
- Check whether the filter in the refrigerant system is blocked
Solution
- Repair the leakage point
- Clean the filter
- Replace the filter
P08High System Pressure (Mid-Pressure Switch)
Auto-reset
Middle-pressure switch MP opened (pressure above 3.0 MPa) while the unit was stopped. Unit remains off until MP closes again (below 2.3 MPa).
Possible causes
- Middle-pressure switch MP on port TS4 is not connected properly or malfunctioned
- Refrigerant system PCB is damaged
How to diagnose
- Check whether the middle pressure switch is open circuit when you turn off the unit
Solution
- Replace the middle pressure switch
P10Low Refrigerant Pressure (Cooling Mode Only)
Manual restart needed
After 1 minute in cooling mode, LPS pressure stayed below 0.7 MPa for 2 minutes. May restart after 10 minutes. After 3 occurrences within 1 hour, manual restart required.
Possible causes
- Refrigerant leak — system is undercharged
- Blockage on the low-pressure side
- Electronic expansion valve (EEV) is stuck
- Poor heat transfer on heat exchangers
- Insufficient water flow rate
- Low pressure sensor LPS is faulty
- Refrigerant system PCB is damaged
How to diagnose
- Check whether the system is leaking
- Check if the filter net is blocked
- Check whether the ambient and water temperature exceeds the limit
Solution
- Repair the leak and refill the refrigerant
- Replace the filter
- Exceeding the system working limit — unit cannot run
P11DC Fan 1 Failure
Manual restart needed
DC fan error. After 10 occurrences within 2 hours the unit shuts down permanently until manual restart. Address promptly to avoid further damage.
Possible causes
- Strong wind causing wrong rotation direction
- Fan power or communication wires not connected properly
- Fan motor blocked or malfunctioned
- Abnormal power supply voltage
- Drive PCB is damaged
How to diagnose
- Check whether the fan is stuck or replace with a new fan
- Replace the main control board
Solution
- Check if the fan is stuck, or replace with a new fan
- Replace the main control board
P134-Way Valve Shifting Failure
Manual restart needed
In heating/DHW mode, inlet temp TA detected higher than outlet TB for 60 seconds — 4-way valve did not switch. After 3 consecutive stop-restart cycles, unit locks out.
Possible causes
- Refrigerant leak — system is undercharged
- 4-way valve body is stuck (dirt, mechanical fault)
- 4-way valve coil has a short or open circuit
- 4-way valve not being energised correctly
- Refrigerant system PCB is damaged
How to diagnose
- Check whether the entering/leaving temperature sensors are reversely inserted
- Check whether the action of the 4-way valve is normal
- Check whether the sample temperature of the motherboard is accurate
Solution
- Correct the wrong sensor placement
- Try to switch repeatedly — if it works, monitor; if not, replace the valve
- If the valve is faulty, replace it
P14Refrigerant Leakage Fault
Manual restart needed
A refrigerant leakage sensor has triggered. Unit shuts down immediately. Manual restart required before the unit can be turned on again.
Possible causes
- Actual refrigerant leak in the system
- Refrigerant leakage sensor is faulty or not connected properly
- Refrigerant system PCB is damaged
How to diagnose
- Check whether there is leakage in the refrigeration system
- Check whether the refrigerant leakage sensor is normal
- Check whether the PCB is faulty
Solution
- Fix leakage in refrigeration system
- Replace the refrigerant leakage sensor
- Replace the PCB
P21Built-in DC Water Pump Abnormal
Auto-reset
The internal DC circulation pump reported an abnormal operating state.
Possible causes
- Pump power supply wires are loose
- PWM input or output wires are loose
- Supply voltage outside the 198–253 V range
- DC water pump is damaged
- Hydraulic module PCB is damaged
How to diagnose
- Check whether the water pump is blocked, or replace with a new pump
- Check whether the system is short of water, whether the valve is closed
- Replace the main control board
Solution
- Check if the water pump is blocked, or replace with a new pump
- Refill water or clean/replace the filter net and open the valve
- Replace the main control board
P25Outlet Water Pressure Sensor Error
Auto-reset
Error in the outlet water pressure sensor. If no other faults are present, the heat pump continues to operate.
Possible causes
- Pressure sensor connection on the hydraulic module PCB is loose
- Sensor is plugged into the wrong port
- Water pressure sensor is short-circuited or malfunctioned
- Hydraulic module PCB is damaged
How to diagnose
- Use a multimeter to check whether the sensor and connection are abnormal
- Replace the faulty sensor with a normal sensor to confirm whether it is normal
- Replace the main control board and confirm whether it is normal
Solution
- Repair the connecting wire and plug or replace the sensor
- Replace the motherboard
E-codes — Sensor & Component Errors39
E01Communication Error — Hydraulic Module ↔ User Interface
Manual restart needed
Communication between the hydraulic module PCB and the user interface has failed. The unit shuts down.
Possible causes
- Communication wires A/B are loose, disconnected, or incorrectly connected
- Wires not in daisy-chain topology
- High-voltage (220 V+) wires too close to communication wires
- Electromagnetic interference from nearby transformer or strong fluorescent lamp
- User interface is damaged
- Hydraulic module PCB is damaged
How to diagnose
- Check whether the communication cable is open or the plug is in poor contact
- Confirm the wire controller is normal on a normal machine
- Use a normal wire controller to confirm whether it is normal on the faulty machine
Solution
- Replace the communication cable or repair it
- Replace the line controller
- Replace the main control board
E02Discharge Temperature Sensor (TP) Error
Manual restart needed
The discharge temperature sensor TP has reported an error or is not connected.
Possible causes
- Sensor connector on the refrigerant system PCB is loose
- Sensor cable short-circuited or resistance out of range
- Temperature sensor TP is faulty — replace sensor
- Refrigerant system PCB is damaged
How to diagnose
- Use a multimeter to check whether the sensor and connection are abnormal
- Replace the faulty sensor with a normal sensor to confirm
- Replace the main control board and confirm whether it is normal
Solution
- Repair the connecting wire and plug or replace the sensor
- Replace the motherboard
E03Coil Temperature Sensor (T3) Error
Manual restart needed
The coil temperature sensor T3 has reported an error.
Possible causes
- Sensor connector on the refrigerant system PCB is loose
- Sensor cable short-circuited or resistance out of range
- Temperature sensor T3 faulty — replace sensor
- Refrigerant system PCB is damaged
How to diagnose
- Use a multimeter to check whether the sensor and connection are abnormal
- Replace the faulty sensor with a normal sensor to confirm
- Replace the main control board and confirm
Solution
- Repair the connecting wire and plug or replace the sensor
- Replace the motherboard
E04Outdoor Ambient Temperature Sensor (T4/TA) Error
Manual restart needed
The outdoor ambient temperature sensor has reported an error.
Possible causes
- Sensor connector on the refrigerant system PCB is loose
- Sensor cable short-circuited or resistance out of range
- Temperature sensor faulty — replace sensor
- Refrigerant system PCB is damaged
How to diagnose
- Use a multimeter to check whether the sensor and connection are abnormal
- Replace the faulty sensor with a normal sensor to confirm
- Replace the main control board and confirm
Solution
- Repair the connecting wire and plug or replace the sensor
- Replace the motherboard
E05Refrigerant Liquid Temperature Sensor (T5) Error
Manual restart needed
The refrigerant liquid temperature sensor T5 has reported an error.
Possible causes
- Sensor connector on the refrigerant system PCB is loose
- Sensor cable short-circuited or resistance out of range
- Temperature sensor T5 faulty — replace sensor
- Refrigerant system PCB is damaged
How to diagnose
- Use a multimeter to check whether the sensor and connection are abnormal
- Replace the faulty sensor with a normal sensor to confirm
- Replace the main control board and confirm
Solution
- Repair the connecting wire and plug or replace the sensor
- Replace the motherboard
E06Suction Temperature Sensor (TH) Error
Manual restart needed
The suction temperature sensor has reported an error.
Possible causes
- Sensor connector on the refrigerant system PCB is loose
- Sensor cable short-circuited or resistance out of range
- Temperature sensor faulty — replace sensor
- Refrigerant system PCB is damaged
How to diagnose
- Use a multimeter to check whether the sensor and connection are abnormal
- Replace the faulty sensor with a normal sensor to confirm
- Replace the main control board and confirm
Solution
- Repair the connecting wire and plug or replace the sensor
- Replace the motherboard
E07Domestic Water Temperature Sensor (TW) Error
Manual restart needed
The domestic hot water temperature sensor TW has reported an error.
Possible causes
- Sensor connector on the hydraulic module PCB is loose
- Sensor cable short-circuited or resistance out of range
- Temperature sensor TW faulty — replace sensor
- Hydraulic module PCB is damaged
How to diagnose
- Use a multimeter to check whether the sensor and connection are abnormal
- Replace the faulty sensor with a normal sensor to confirm
- Replace the main control board and confirm
Solution
- Repair the connecting wire and plug or replace the sensor
- Replace the motherboard
E08Inlet Water Temperature Sensor (TA) Error
Manual restart needed
The inlet water temperature sensor TA has reported an error.
Possible causes
- Sensor connector on the hydraulic module PCB is loose
- Sensor cable short-circuited or resistance out of range
- Temperature sensor TA faulty — replace sensor
- Hydraulic module PCB is damaged
How to diagnose
- Use a multimeter to check whether the sensor and connection are abnormal
- Replace the faulty sensor with a normal sensor to confirm
- Replace the main control board and confirm
Solution
- Repair the connecting wire and plug or replace the sensor
- Replace the motherboard
E09Outlet Water Temperature Sensor (TB) Error
Manual restart needed
The outlet water temperature sensor TB has reported an error.
Possible causes
- Sensor connector on the hydraulic module PCB is loose
- Sensor cable short-circuited or resistance out of range
- Temperature sensor TB faulty — replace sensor
- Hydraulic module PCB is damaged
How to diagnose
- Use a multimeter to check whether the sensor and connection are abnormal
- Replace the faulty sensor with a normal sensor to confirm
- Replace the main control board and confirm
Solution
- Repair the connecting wire and plug or replace the sensor
- Replace the motherboard
E10Communication Error — Refrigerant PCB ↔ Drive PCB
Manual restart needed
Communication between the refrigerant system PCB and the hydraulic module PCB has failed.
Possible causes
- Communication cable between PCBs is loose
- Short or open circuit on communication line
- Electromagnetic interference from nearby equipment
- Hydraulic module PCB is damaged
- Refrigerant system PCB is damaged
How to diagnose
- Check whether the communication cable is open or plug is in poor contact
- Replace the main control board and confirm whether it is normal
- Replace the drive board and confirm whether it is normal
Solution
- Replace or repair the communication cable
- Replace the main control board
- Replace the drive module
E13Discharge Pressure Sensor Error
Manual restart needed
The high-pressure sensor on the discharge side has reported a fault.
Possible causes
- Pressure sensor connection on the refrigerant system PCB is loose
- Pressure sensor short-circuited or malfunctioned
- Refrigerant system PCB is damaged
How to diagnose
- Check whether the sensor and connection are abnormal
- Replace the faulty sensor with a normal sensor to confirm
- Replace the main control board and confirm
Solution
- Repair the connecting wire and plug or replace the sensor
- Replace the motherboard
E14Low Pressure Sensor (LPS) Error
Manual restart needed
The low-pressure sensor LPS has reported a fault.
Possible causes
- Pressure sensor connection on the refrigerant system PCB is loose
- Pressure sensor short-circuited or malfunctioned
- Refrigerant system PCB is damaged
How to diagnose
- Check whether the sensor and connection are abnormal
- Replace the faulty sensor with a normal sensor to confirm
- Replace the main control board and confirm
Solution
- Repair the connecting wire and plug or replace the sensor
- Replace the motherboard
E15DC Bus Voltage Too Low
Auto-reset
The DC bus voltage in the inverter module has fallen below the minimum threshold.
Possible causes
- Abnormal AC input power supply
- Inverter module PCB is damaged
How to diagnose
- Check whether the wiring is wrong
Solution
- Reconnect the cable or replace the IPM module
E16DC Bus Voltage Too High
Auto-reset
The DC bus voltage in the inverter module has exceeded the maximum threshold.
Possible causes
- Abnormal AC input power supply (voltage spike)
- Inverter module PCB is damaged
How to diagnose
- Check whether the wiring is wrong
Solution
- Reconnect the cable or replace the IPM module
E17AC Input Peak Current Too High
Auto-reset
The AC input current to the inverter exceeded the peak current limit.
Possible causes
- Abnormal or fluctuating AC power supply
- Inverter module PCB is damaged
How to diagnose
- Check whether the wiring is wrong
Solution
- Reconnect the cable or replace the IPM module
E18IPM Module Abnormal
Manual restart needed
The Intelligent Power Module (IPM) inside the inverter has reported a fault.
Possible causes
- Overtemperature or overcurrent in the IPM module
- Drive PCB is damaged
How to diagnose
- Check whether the wiring is wrong
Solution
- Reconnect the cable or replace the IPM module
E19PFC Module Abnormal
Manual restart needed
The Power Factor Correction (PFC) module has reported a fault.
Possible causes
- Abnormal AC input power supply
- Drive PCB (PFC section) is damaged
How to diagnose
- Check whether the wiring is wrong
Solution
- Reconnect the cable or replace the IPM module
E20Compressor Startup Failure
Auto-reset
The inverter-driven compressor failed to start successfully.
Possible causes
- Abnormal power supply voltage
- Compressor damaged or mechanically seized
- Drive PCB is damaged
How to diagnose
- Check whether the wiring is wrong
Solution
- Reconnect the cable or replace the IPM module
E21Compressor Phase Loss
Manual restart needed
One or more phases of the compressor power supply are missing.
Possible causes
- Compressor wiring (U/V/W) is loose or broken
- Compressor winding is damaged
- Drive PCB is damaged
How to diagnose
- Check whether the wiring is wrong
Solution
- Reconnect the cable or replace the IPM module
E22Inverter Module Reset
Auto-reset
The compressor inverter module is performing a reset. Not necessarily a fault — the unit may restart automatically.
Possible causes
- Normal reset cycle after a transient condition
- Drive PCB instability
How to diagnose
- Check whether the wiring is wrong
Solution
- Reconnect the cable or replace the IPM module
E23Compressor Current Too High
Auto-reset
Compressor operating current exceeded the protection threshold.
Possible causes
- Mechanical overload on the compressor
- Refrigerant system pressure too high
- Drive PCB is damaged
How to diagnose
- Check whether the wiring is wrong
Solution
- Reconnect the cable or replace the IPM module
E24PFC Module Temperature Too High
Auto-reset
The PFC module temperature has exceeded its protection threshold.
Possible causes
- Poor ventilation around the electrical cabinet
- Drive PCB cooling system insufficient
- Drive PCB is damaged
How to diagnose
- Check whether the wiring is wrong
Solution
- Reconnect the cable or replace the IPM module
E25Current Detection Circuit Failure
Manual restart needed
A fault was detected in the current measurement circuit of the inverter.
Possible causes
- Drive PCB current sensor is damaged
- Drive PCB is damaged
How to diagnose
- Check whether the wiring is wrong
Solution
- Reconnect the cable or replace the IPM module
E26Compressor Out-of-Step
Auto-reset
The inverter lost synchronisation with the compressor motor (step-out).
Possible causes
- Abnormal load on the compressor
- Refrigerant system overpressure
- Drive PCB is damaged
How to diagnose
- Check whether the wiring is wrong
Solution
- Reconnect the cable or replace the IPM module
E27PFC Module Temperature Sensor Error
Manual restart needed
The temperature sensor of the PFC module has reported a fault.
Possible causes
- PFC temperature sensor is loose or damaged
- Drive PCB is damaged
How to diagnose
- Check whether the wiring is wrong
Solution
- Reconnect the cable or replace the IPM module
E28Communication Error — Refrigerant PCB ↔ Inverter PCB
Manual restart needed
Communication between the refrigerant system PCB and the inverter (drive) PCB has failed.
Possible causes
- Communication cable between PCBs is loose or damaged
- Electromagnetic interference
- Refrigerant system PCB or drive PCB is damaged
How to diagnose
- Check whether the wiring is wrong
Solution
- Reconnect the cable or replace the IPM module
E29IPM Module Temperature Too High
Auto-reset
The Intelligent Power Module (IPM) temperature has exceeded its protection limit.
Possible causes
- Poor ventilation or blocked airflow over the drive PCB heatsink
- Drive PCB cooling insufficient
- Drive PCB is damaged
How to diagnose
- Check whether the wiring is wrong
Solution
- Reconnect the cable or replace the IPM module
E30IPM Module Temperature Sensor Error
Manual restart needed
The temperature sensor of the IPM module has reported a fault.
Possible causes
- IPM temperature sensor is loose or damaged
- Drive PCB is damaged
How to diagnose
- Check whether the wiring is wrong
Solution
- Reconnect the cable or replace the IPM module
E36Abnormal AC Input Power Supply
Auto-reset
The AC mains supply to the unit is outside acceptable parameters.
Possible causes
- Mains voltage is too high or too low
- Phase imbalance or phase loss in three-phase supply
- Supply wiring or circuit breaker issue
How to diagnose
- Check whether the wiring is wrong
Solution
- Reconnect the cable or replace the IPM module
E49Final Water Temperature Sensor (TC) Error
Manual restart needed
The final (zone) water temperature sensor TC has reported an error.
Possible causes
- Sensor connector on the hydraulic module PCB is loose
- Sensor cable short-circuited or resistance out of range
- Temperature sensor TC faulty — replace sensor
- Hydraulic module PCB is damaged
How to diagnose
- Check whether the wiring is wrong
- Reconnect the cable or replace the IPM module
Solution
- Check whether the wiring is wrong
- Reconnect the cable or replace the IPM module
E50Solar Temperature Sensor (Tso) Error
Manual restart needed
The solar collector temperature sensor Tso has reported an error.
Possible causes
- Sensor connector is loose
- Sensor is short-circuited or faulty
- Hydraulic module PCB is damaged
How to diagnose
- Check whether the wiring is wrong
- Reconnect the cable or replace the IPM module
Solution
- Check whether the wiring is wrong
- Reconnect the cable or replace the IPM module
E51Wire Controller Built-in Sensor (Tro) Error
Manual restart needed
The built-in temperature sensor Tro inside the wired controller has reported a fault.
Possible causes
- Wired controller is damaged
- Hydraulic module PCB is damaged
How to diagnose
- Check whether the wiring is wrong
- Reconnect the cable or replace the IPM module
Solution
- Check whether the wiring is wrong
- Reconnect the cable or replace the IPM module
E52Zone 2 Temperature Sensor (TZ2) Error
Manual restart needed
The Zone 2 water temperature sensor TZ2 has reported an error.
Possible causes
- Sensor connector on the hydraulic module PCB is loose
- Sensor is short-circuited or faulty
- Hydraulic module PCB is damaged
How to diagnose
- Check whether the wiring is wrong
- Reconnect the cable or replace the IPM module
Solution
- Check whether the wiring is wrong
- Reconnect the cable or replace the IPM module
E53Buffer Tank Upper Temperature Sensor (TE1) Error
Manual restart needed
The upper temperature sensor TE1 of the buffer tank has reported an error.
Possible causes
- Sensor connector on the hydraulic module PCB is loose
- Sensor is short-circuited or faulty
- Hydraulic module PCB is damaged
How to diagnose
- Check whether the wiring is wrong
- Reconnect the cable or replace the IPM module
Solution
- Check whether the wiring is wrong
- Reconnect the cable or replace the IPM module
E54Buffer Tank Lower Temperature Sensor (TE2) Error
Manual restart needed
The lower temperature sensor TE2 of the buffer tank has reported an error.
Possible causes
- Sensor connector on the hydraulic module PCB is loose
- Sensor is short-circuited or faulty
- Hydraulic module PCB is damaged
How to diagnose
- Check whether the wiring is wrong
- Reconnect the cable or replace the IPM module
Solution
- Check whether the wiring is wrong
- Reconnect the cable or replace the IPM module
E56Outlet Water Pressure Sensor (PS1) Error
Manual restart needed
The outlet water pressure sensor PS1 has reported an error.
Possible causes
- Sensor connector on the hydraulic module PCB is loose
- Sensor is plugged into the wrong port
- Pressure sensor short-circuited or faulty
- Hydraulic module PCB is damaged
How to diagnose
- Check whether the wiring is wrong
- Reconnect the cable or replace the IPM module
Solution
- Check whether the wiring is wrong
- Reconnect the cable or replace the IPM module
E57Gas Sensor Offline
Manual restart needed
The gas (refrigerant leakage) sensor has gone offline — no communication received. For CASCADE applications this indicates a communication error between master and slave modules — check wiring.
Possible causes
- Gas sensor communication wiring is loose or disconnected
- Gas sensor is not powered
- Gas sensor module is damaged
How to diagnose
- Check whether the wiring between master and slave modules is correct
Solution
- Reconnect or repair the communication wiring between modules
E58Gas Sensor Fault
Manual restart needed
The gas (refrigerant leakage) sensor has reported an internal fault.
Possible causes
- Gas sensor has detected a fault in its own self-test
- Gas sensor is damaged — replace sensor
How to diagnose
- Check whether the wiring between modules is correct
Solution
- Reconnect or repair the communication wiring between modules
E59Module Offline
Manual restart needed
A system module has gone offline and is not communicating.
Possible causes
- Communication wiring between modules is loose or disconnected
- Module is not powered
- Module is damaged
How to diagnose
- Check whether the wiring between modules is correct
Solution
- Reconnect or repair the communication wiring between modules