Fault code lookup

Indoor room/return air thermistor abnormality.

Indoor pipe (liquid) thermistor abnormality.

Drain float switch / drain sensor circuit open.

Drain pump abnormality / drain overflow protection.

Freeze-up or overheat protection operating on the indoor coil.

Indoor pipe temperature abnormality (heat exchanger).

Indoor gas pipe thermistor abnormality (dual sensor).

Forced compressor stop — suspected refrigerant shortage or wet operation.

Indoor fan motor abnormality.

Remote controller transmission error (no signal received).

Remote controller board / processor error.

Remote controller address setting error.

Remote controller signal collision / transmission failure.

Remote controller receive error.

Indoor/outdoor transmission error detected indoors.

Indoor/outdoor unit communication abnormality.

Indoor unit signal receive error from outdoor unit.

Indoor/outdoor transmission error (outdoor detection).

Indoor unit not detected / all units offline on the bus.

Number of connected indoor units incorrect / wiring mismatch.

Indoor unit address duplication.

Combination or capacity setting error between units.

M-NET / centralised control transmission processor error.

High pressure abnormality (63H protection operating).

Abnormal high discharge temperature / compressor shell temperature.

Discharge thermistor open/short circuit.

Outdoor thermistor (ambient, pipe or heat sink) open/short circuit.

Heat sink / power module temperature abnormality.

Power module / IPM overcurrent detected.

Superheat abnormality due to low discharge temperature.

Outdoor fan motor protection operating.

Inverter bus voltage abnormality (over/under voltage).

Compressor overcurrent / current sensor abnormality.

Compressor start-up current abnormality / locked rotor.

Low pressure abnormality (63L operating).

Compressor overcurrent interruption at start-up.

Current sensor / primary current abnormality.

Abnormal low pressure detected during operation.

Compressor overcurrent protection (thermal) operating.

63L connector open / low pressure switch circuit open.

63H connector open / high pressure switch circuit open.

Two or more connectors open on the outdoor board.

L2 phase open or 51CM connector open (3-phase units).

City Multi outdoor unit — indoor/BC controller communication error.

City Multi communication error between outdoor units.

City Multi transmission wiring / signal quality error.

City Multi power supply / transmission line voltage error.

Ecodan flow temperature overheat protection.

Ecodan DHW tank temperature sensor fault.

Ecodan immersion heater / booster heater circuit fault.

Ecodan water-side freeze protection operating.

Ecodan heating operation error (flow temperature not achieved).

Ecodan low primary flow rate detected.

Ecodan pressure sensor / flow sensor abnormality.

Ecodan boiler / external heat source communication error.

Ecodan thermistor abnormality on the water circuit.

Ecodan hydrobox operation error.

Ecodan boiler flow temperature abnormality.

Ecodan DHW operation error.

Ecodan dip switch / setting error on the hydrobox.

Ecodan flow rate below minimum during defrost.

External protection device tripped (indoor).

Indoor PCB abnormality (EEPROM / self-check).

Condensate drain level control abnormality.

Indoor freeze-up prevention / high pressure control.

Indoor fan motor overload, overcurrent or lock.

Swing flap motor abnormality.

Indoor unit AC input overcurrent.

Electronic expansion valve drive abnormality (indoor).

Drain level abnormal — humidifier / drain system.

Air filter / dust collector abnormality.

Capacity setting abnormality (indoor capacity chip).

Indoor liquid pipe thermistor abnormality.

Indoor gas pipe thermistor abnormality.

Front panel / louvre limit switch abnormality.

Indoor return air thermistor abnormality.

Indoor discharge air thermistor abnormality.

Humidity sensor system abnormality.

Remote controller thermistor abnormality.

Safety device (outdoor) activated.

Outdoor PCB abnormality.

High pressure switch / HP protection activated.

Low pressure abnormality detected.

Compressor motor overload / inverter compressor lock.

Compressor start-up failure / overcurrent (standard compressor).

Outdoor fan motor abnormality or fan lock.

Outdoor unit AC input overcurrent.

Outdoor electronic expansion valve drive abnormality.

Four-way reversing valve abnormality (cooling/heating changeover).

Water temperature abnormality (Altherma / water-cooled).

Drain water level abnormality (outdoor / water system).

Discharge pipe temperature abnormally high.

Refrigerant overcharge / high pressure in cooling.

Compressor sensor system abnormality (voltage/current sensing).

High pressure switch circuit abnormality.

Compressor position detection abnormality (no feedback).

Outdoor fan motor signal abnormality.

Compressor input current abnormality / CT fault.

Outdoor air thermistor abnormality.

Pressure sensor abnormality.

Current sensor abnormality.

Discharge pipe thermistor abnormality.

Suction pipe thermistor abnormality.

Outdoor heat exchanger (coil) thermistor abnormality.

Liquid pipe / receiver thermistor abnormality.

Liquid line thermistor abnormality (subcool circuit).

Gas line thermistor abnormality (subcool circuit).

Discharge pressure sensor abnormality.

Suction pressure sensor abnormality.

Inverter PCB abnormality.

Electrical box temperature rise / control box overheat.

Inverter heat sink temperature rise.

Inverter instantaneous overcurrent (compressor earth/short).

Inverter compressor overcurrent / motor wire disconnection.

Compressor stall prevention error (start-up).

Transmission error between inverter and control PCB.

Central control PCB abnormality.

Transmission error between central control devices.

Improper combination of centralised control devices.

Centralised address duplication.

Inverter power supply open phase / voltage imbalance.

Heat sink temperature sensor abnormality.

Outdoor capacity setting abnormality.

Refrigerant shortage / low suction superheat protection.

Reverse phase or open phase on the supply.

Power supply voltage abnormality / bus voltage insufficient.

Test run not performed / commissioning incomplete.

Communication error between indoor and outdoor units.

Communication error between indoor unit and remote controller.

Communication error between outdoor units.

Communication error between main and sub remote controllers.

Another indoor unit on the same system is in error.

Indoor/outdoor combination or refrigerant type mismatch.

Centralised control address duplication.

Communication error between indoor unit and centralised controller.

Piping/wiring mismatch or commissioning not completed.

Refrigerant system address not set / abnormality.

Wired remote controller not receiving indoor signal.

Remote controller transmission error.

Communication lost between indoor unit and remote controller.

Indoor/outdoor communication circuit error (indoor detection).

Reduced number of indoor units detected by outdoor unit.

Indoor/outdoor communication circuit error (outdoor detection).

Duplicated indoor unit address.

Duplicated master remote controller setting.

Indoor unit internal communication error (MCU).

Automatic address setting error.

No indoor unit found during automatic addressing.

Too many indoor units / capacity over connection.

Communication error between indoor units (group control).

Outdoor header unit quantity error.

Other refrigerant line connected during addressing.

Transmission error between outdoor units.

Duplicated outdoor follower address.

Reduced number of connected outdoor units.

Outdoor follower unit error — check the follower's own code.

Outdoor inverter PCB communication error (IPDU).

Indoor heat exchanger sensor TCJ error.

Indoor heat exchanger sensor TC2 error.

Indoor heat exchanger sensor TC1 error.

Discharge temperature sensor TD1 error.

Discharge temperature sensor TD2 error.

Outdoor heat exchanger sensor TE/TE1 error.

Liquid temperature sensor TL error.

Outdoor ambient sensor TO error.

Indoor return air sensor TA error.

Indoor room temperature sensor TA error.

Suction temperature sensor TS1 error.

Heat sink / IGBT temperature sensor TH error.

Outdoor temperature sensor wiring error (TE/TL interchanged).

Outdoor pressure sensor wiring error (Pd/Ps interchanged).

Low pressure sensor Ps output error.

High pressure sensor Pd output error.

Indoor PCB other error (EEPROM).

Outdoor PCB error (EEPROM / self-diagnosis).

Compressor breakdown — inverter current detection.

Compressor lock / locked rotor detected.

Current detection circuit error.

Compressor 1 case thermostat operated.

Discharge sensor TD1 miswiring / not fitted.

Low pressure protection operating (Ps).

Low oil level protection operating.

Oil level detection temperature sensor error.

Compressor 2 case thermostat operated.

Oil level detection circuit error / magnetic switch fault.

Indoor/outdoor unit type mismatch.

Duplicated indoor group master unit.

Duplicated outdoor line (refrigerant system) address.

Duplicated priority indoor unit.

Two or more indoor units set as priority.

Group line in an individual indoor unit.

Indoor group or address not set.

Indoor capacity not set.

Outdoor capacity / service PCB setting not made.

Duplicated central control address.

Number of IPDU / inverter boards incorrect.

External interlock input to the indoor unit.

Extended IC error / phase or supply abnormality.

Indoor fan motor error (feedback lost or overload).

Discharge temperature TD1 abnormally high.

High pressure switch operating (Pd).

Open phase / supply voltage abnormality detected.

Heat sink overheat protection operating.

Indoor unit water overflow / float switch operated.

Indoor DC fan motor error.

Outdoor liquid backflow detection error.

Gas leak detection (TS condition).

Discharge temperature TD2 abnormally high.

Four-way valve reverse operation error.

High pressure protection operating.

Outdoor fan drive (IPDU) error.

Inverter output short circuit / G-Tr protection operating.

Compressor position detection circuit error.

Other indoor unit in the group is in error (follower stop).

Central control device transmission error (send).

Central control device transmission error (receive).

General-purpose interface batch alarm.

Indoor unit serial communication error (to outdoor).

Indoor/outdoor unit model or capacity mismatch.

Remote controller communication error.

Network communication error between indoor units.

Indoor unit address setting error / duplication.

Indoor unit EEPROM access error.

Multiple remote controller master setting error.

Indoor/outdoor serial reverse transfer error.

Indoor unit PCB EEPROM / microcontroller error.

Indoor unit main PCB abnormality.

Indoor unit power supply / voltage abnormality.

Indoor unit drain float switch / water level error.

Indoor unit manual auto switch error.

Indoor unit filter / dust sensor error.

Indoor unit fan motor error (lock or feedback).

Indoor unit fan speed out of range.

Indoor unit louvre motor error.

Indoor unit drain pump error.

Indoor unit humidifier error.

Indoor unit damper / vent motor error.

Indoor room temperature thermistor open or short.

Indoor heat exchanger inlet thermistor error.

Indoor heat exchanger middle thermistor error.

Indoor heat exchanger outlet thermistor error.

Indoor discharge air thermistor error.

Remote controller thermistor error.

Indoor unit humidity sensor error.

Outdoor unit PCB / EEPROM error.

Outdoor unit inverter PCB communication error.

Inverter DC bus voltage error (high or low).

Outdoor unit current sensor error.

Active filter / power module error.

Outdoor unit power supply open phase or reverse phase.

Outdoor unit fan motor 1 error.

Outdoor unit fan motor 2 error.

Outdoor ambient thermistor open or short.

Outdoor heat exchanger thermistor error.

Discharge temperature thermistor error.

Compressor temperature thermistor error.

Suction gas thermistor error.

Sub-cool heat exchanger thermistor error.

Liquid pipe thermistor error.

Heat sink thermistor error.

Discharge temperature abnormally high — protection stop.

Compressor temperature abnormally high.

High pressure switch / high pressure protection operating.

Low pressure abnormality — suspected refrigerant shortage.

High pressure sensor error.

Low pressure sensor error.

Heat sink overheat protection operating.

Compressor overcurrent / inverter current protection.

Expansion valve (EEV) coil or drive error.

Four-way valve / changeover valve error.

Solenoid / bypass valve error.

Current sensor abnormality on the compressor circuit.

Compressor start-up failure / rotor position error.

Compressor discharge pressure ratio abnormality.

Outdoor unit branch box / distribution unit communication error.

Branch box wiring or address error.

Inverter compressor motor wiring error or open winding.

Trip detection — inverter protection repeated.

Refrigerant circuit / piping installation error detected.

Outdoor unit test run or commissioning incomplete.

Outdoor unit fan protection repeated stop.

Discharge superheat abnormality (low superheat / liquid return).

Outdoor unit multiple protection stop — check history.