Alpha Heating Innovation (Alpha Therm) · A niche brand in the UK. 99 codes across 2 product families, each taken from the manufacturer’s manuals. Alpha Heating Innovation technical support ↗
Filter by product family
Type the code on your display or a word from its meaning. Each code opens its own page with what it means, whether it is safe and what you can check.
99 codes
| Code | Meaning | Stops? | Homeowner check? |
|---|---|---|---|
| 1006 | Return sensor fault: Incorrect reading from heat pump return sensor (water inlet) | Not stated | Yes |
| 1008 | Flow sensor fault: Incorrect reading from heat pump flow sensor (water outlet) | Not stated | Yes |
| 1015 | Flow temperature increase (during DHW): Abnormal flow temperature increase in the outdoor unit during DHW mode | Not stated | Yes |
| 1016 | Flow temperature increase: Abnormal flow temperature increase in the outdoor unit | Not stated | Yes |
| 1019 | System water high temperature: System water circuit overheating | Not stated | Yes |
| 1020 | Power supply voltage anomaly: The supply voltage to the outdoor unit is out of the normal range | Not stated | Yes |
| 1021 | High pressure error: Outdoor unit evaporator/condenser fault (evaporator temperature below 0°C or condenser temperature >= 59.5°C) | Not stated | Yes |
| 1022 | Overheat: Outdoor unit sensors overheat anomaly | Not stated | Yes |
| 1024 | DHW cylinder overheat: DHW cylinder high temperature reading | Not stated | Yes |
| 1026 | DHW cylinder heating: DHW heating time greater than 6 hours | Not stated | Yes |
| 1032 | Liquid probe error: Compressor liquid phase temperature sensor fault | Not stated | Yes |
| 1036 | PCB fault detected: EEPROM control board error | Not stated | Yes |
| 1039 | High pressure switch fault: High pressure switch intervention | Not stated | Yes |
| 1040 | High pressure switch fault: The pressure sensor has activated repeatedly (16 times in 300 minutes) | Not stated | Yes |
| 1043 | Compressor overload: Compressor inverter overheat detected | Not stated | Yes |
| 1044 | Compressor start anomaly: Compressor motor rotation anomaly | Not stated | Yes |
| 1045 | Fan anomaly: Fan stopped on start up | Not stated | Yes |
| 1046 | Fan anomaly: Fan rotation anomaly | Not stated | Yes |
| 1050 | Compressor high current anomaly: Compressor power supply voltage too high | Not stated | Yes |
| 1054 | DHW temperature fault: Abnormal DHW temperature increase | Not stated | Yes |
| 1057 | Power supply voltage to compressor: Compressor power supply voltage out of range before start up | Not stated | Yes |
| 1060 | High pressure switch error: High pressure switch fault | Not stated | Yes |
| 1064 | Compressor start anomaly: The compressor does not start up properly | Not stated | Yes |
| 1065 | Compressor anomaly: Compressor power supply BUS not coherent | Not stated | Yes |
| 1066 | External temperature sensor error: Outdoor air temperature sensor anomaly | Not stated | Yes |
| 1072 | High discharge temperature: Compressor discharge temperature too high | Not stated | Yes |
| 1077 | High external coil temperature: High temperature on external coil | Not stated | Yes |
| 1078 | High pressure on external coil: Pressure too high on external coil | Not stated | Yes |
| 1079 | Pressure sensor anomaly: Detected cooling gas pressure out of range | Not stated | Yes |
| 1080 | Coolant pressure probe anomaly: Coolant pressure probe anomaly | Not stated | Yes |
| 1081 | Discharge probe anomaly: Compressor temperature sensor anomaly | Not stated | Yes |
| 1083 | Evaporator probe anomaly: Outdoor coil temperature anomaly | Not stated | Yes |
| 1103 | High inverter temperature: Inverter board temperature too high | Not stated | Yes |
| 1104 | Inverter temperature increased abnormally: Temperature on cooling fins too high | Not stated | Yes |
| 1105 | Inverter high current: High current detected on inverter | Not stated | Yes |
| 1118 | Inverter temperature sensor fault: Inverter temperature sensor anomaly | Not stated | Yes |
| 1119 | Coolant loss: Lack of coolant in outdoor unit | Not stated | Yes |
| 1123 | Power supply voltage anomaly: Power supply voltage out of range | Not stated | Yes |
| 1128 | Communication error with outdoor unit boards: Inverter communication error - hydronic board | Not stated | Yes |
| A101 | Outdoor unit communication error | Yes | Yes |
| A109 | Communication error due to incorrect address of interface board | Yes | Yes |
| A122 | MODBUS communication error | Yes | Yes |
| A162 | EEPROM error | Yes | Yes |
| A177 | Emergency error | Yes | Yes |
| A198 | Error of thermal fuse terminal board (open) | Yes | Yes |
| A201 | Communication error (failed coupling) between interface board and outdoor unit | Yes | Yes |
| A202 | Communication error (failed coupling) between indoor unit and interface board | Yes | Yes |
| A203 | Communication error between Inverter and main board of the outdoor unit | Yes | Yes |
| A221 | Outdoor unit air temperature sensor error | Yes | Yes |
| A231 | Condenser temperature sensor error | Yes | Yes |
| A251 | Discharge temperature sensor error | Yes | Yes |
| A320 | Compressor sensor error (overload protection sensor) | Yes | Yes |
| A403 | Freezing detection (during cooling operation) | Yes | Yes |
| A404 | Protection of outdoor unit when in overload (during safety start-up, normal operating status) | Yes | Yes |
| A407 | Compressor not working due to high pressure | Yes | Yes |
| A416 | The compressor discharge is overheated | Yes | Yes |
| A430 | Outdoor unit EEV operation error | Yes | Yes |
| A440 | Central heating blocked (outdoor temperature beyond 35°C) | Partly | Yes |
| A441 | Cooling blocked (outdoor temperature below 9°C) | Partly | Yes |
| A458 | Error of outdoor unit fan no.1 | Yes | Yes |
| A461 | Compressor start-up error (Inverter) | Yes | Yes |
| A462 | Inverter total current overload error | Yes | Yes |
| A463 | Compressor overheated sensor | Yes | Yes |
| A464 | Inverter IPM current overload error | Yes | Yes |
| A465 | Compressor overload error | Yes | Yes |
| A466 | Low voltage error of DC circuit | Yes | Yes |
| A467 | Compressor rotation error | Yes | Yes |
| A468 | Current sensor error (inverter) | Yes | Yes |
| A469 | Voltage sensor error of DC circuit (inverter) | Yes | Yes |
| A470 | EEPROM reading/writing error of outdoor unit | Yes | Yes |
| A471 | EEPROM reading/writing error of outdoor unit | Yes | Yes |
| A474 | Inverter temperature sensor error | Yes | Yes |
| A475 | Error of outdoor unit fan no.2 (where present) | Yes | Yes |
| A484 | PFC overload | Yes | Yes |
| A485 | Incoming current sensor error | Yes | Yes |
| A500 | IPM overheated | Yes | Yes |
| A554 | Gas leak error | Yes | Yes |
| A590 | Inverter board error | Yes | Yes |
| E8 | Maximum N° of resets: Number of allowed resets already performed; resets allowed up to 5 times consecutively, then inhibited for at least one hour (one attempt regained per hour; power-cycling restores the 5 attempts) | Yes | Yes |
| E12 | Storage tank probe anomaly (optional): The board detects an anomaly on the storage tank probe; the indoor unit cannot produce domestic hot water | Partly | Yes |
| E15 | Configuration error: Anomaly or incongruity on the electric wiring detected; appliance will not start. Restarts without reset when normal conditions restored | Yes | Yes |
| E24 | Push button control panel anomaly: The board detects an anomaly on the pushbutton panel; restarts without reset when normal conditions restored | Not stated | Yes |
| E26 | System flowmeter anomaly: The board detects an anomaly on the system flowmeter; system does not start; booster pump (if any) always working | Yes | Yes |
| E27 | Circulation insufficient: Overheating in the indoor unit due to insufficient water circulating in the primary circuit: low system circulation (closed shut-off devices, air in system), pump blocked, damaged flowmeter | Yes | Yes |
| E37 | Low power supply voltage: Power supply voltage lower than allowed limits for correct operation; restarts without reset when normal | Yes | Yes |
| E50 | External probe missing or faulty: External probe not connected or faulty; system continues using the probe integrated in the external unit | No | Yes |
| E139 | De-aeration in progress: Deaeration function in progress; no demand can be made until the end of the function | Partly | Yes |
| E177 | DHW maximum time block: Domestic hot water production not met within the pre-established time (parameter P014); system continues with non-optimal performance | No | Yes |
| E178 | Anti-Legionella cycle block not successful: Anti-Legionella cycle not completed within the pre-established time (parameter P013) | No | Yes |
| E182 | Outdoor unit alarm: An anomaly appears on the outdoor unit; the system does not start. Outdoor code is shown as A + code on the control panel | Yes | Yes |
| E183 | Outdoor unit in test mode: Condensing unit is in test mode (triggered during outdoor test); heating and DHW requests cannot be met | Partly | Yes |
| E184 | Communication error with outdoor unit: Anomaly due to a communication problem between the indoor unit and the outdoor unit; system does not start | Yes | Yes |
| E188 | Request with temperature out of range: A request is made with the outdoor temperature exceeding the operating limits; system does not start until within limits | Yes | Yes |
| E189 | Time out alarm with communication board: Communication between the printed circuit boards is lost; system does not start | Yes | Yes |
| E190 | Communication board alarm: An anomaly appears on the communication board; system does not start | Yes | Yes |
| E193 | Appliance in test mode: Appliance is in test mode; system continues operating properly | No | Yes |
| E195 | Liquid phase probe low temperature anomaly: Too low temperature detected in the liquid phase | Not stated | Yes |
| E196 | Flow high temperature block: Excessively high temperature detected on the heat pump flow circuit | Not stated | Yes |
| E197 | Interface Board Configuration Error: Incorrect interface board configuration detected; system does not start | Yes | Yes |