Alpha Heating Innovation is a UK-based boiler manufacturer known for producing reliable, competitively priced gas boilers. Their E-Tec, InTec, and CB ranges are popular choices for both new installations and replacements.
Alpha Boiler Fault Codes
All Alpha Fault Codes 82
| Code | Fault | Severity | Type | View guide |
|---|---|---|---|---|
| 0A1 | Ignition Failure (ProTec Plus) On Alpha ProTec Plus commercial boilers, 0A1 indicates ignition failure — gas supply or valve… | Medium | Engineer | View Guide |
| 0A5 | Fan Speed Fault (ProTec Plus) On Alpha ProTec Plus boilers, 0A5 indicates a fan speed fault — flue or ventilation… | High | Engineer | View Guide |
| 1 | Ignition Failure The boiler has failed to ignite. Possible causes include gas supply issues, defective ignition electrode,… | Medium | DIY Check | View Guide |
| 12 | Cylinder Sensor Fault (FlowSmart) The cylinder temperature sensor has a wiring fault or has failed. Relevant on FlowSmart system… | Medium | Engineer | View Guide |
| 15 | Internal Wiring Error An incorrect wiring configuration has been detected internally. Usually only occurs after maintenance or installation… | High | Engineer | View Guide |
| 16 | Fan Fault The fan has a fault — either a wiring connection issue, a failed fan motor,… | High | Engineer | View Guide |
| 2 | Overheat Boiler Lockout The boiler has overheated and locked out. Caused by pump or flow problems, blocked heat… | High | Engineer | View Guide |
| 20 | Flame Sensing Fault The flame sensing electrode is not detecting the flame correctly, or there is a PCB… | Medium | Engineer | View Guide |
| 24 | Control Panel Button Fault A control panel button is stuck in the ON position, or there is a fault… | Medium | Engineer | View Guide |
| 25 | Overheat Lockout (Secondary) A secondary overheat lockout triggered by air in the heat exchanger, blocked flow, flue restriction,… | High | Engineer | View Guide |
| 27 | Insufficient Primary Flow The boiler is not detecting adequate water flow through the primary circuit. Caused by blockage,… | Medium | Engineer | View Guide |
| 29 | Flue Sensor Fault The flue gas temperature sensor has a wiring fault or has failed. | Medium | Engineer | View Guide |
| 3 | High Flue Temperature The flue gas temperature has reached a dangerous level. Usually caused by a blocked or… | High | Engineer | View Guide |
| 31 | Loss of Communication with External Control The boiler has lost communication with the Alpha Climatic remote control system. | Low | Engineer | View Guide |
| 37 | Low Supply Voltage The mains power supply voltage has dropped below the minimum operating level for the boiler. | Medium | Engineer | View Guide |
| 38 | Loss of Flame Rectification (Type 1) The boiler's flame rectification circuit has detected a fault with the flame — the electrode… | Medium | Engineer | View Guide |
| 4 | Gas Valve Electrical Connection Fault There is an electrical connection fault at the gas valve — either the valve lead… | High | Engineer | View Guide |
| 43 | Loss of Flame Rectification (Type 2) Persistent flame rectification loss — similar to code 38 but indicating a more established problem… | Medium | Engineer | View Guide |
| 44 | Safety Lockout — External Control Cycling The boiler has locked out due to too many rapid on/off requests from an external… | Medium | DIY Check | View Guide |
| 46 | External Sensor Fault The optional external temperature sensor (for weather compensation) has a wiring fault or has failed. | Low | Engineer | View Guide |
| 47 | Reduced Burner Output — Flue Thermostat Active The flue thermostat has sensed high flue gas temperature and reduced the burner output as… | Medium | Engineer | View Guide |
| 49 | Return Sensor High Temperature The return sensor has detected an unusually high temperature on the heat exchanger return circuit,… | Medium | Engineer | View Guide |
| 5 | Heating Flow Sensor Fault The central heating flow temperature sensor has a wiring fault or the sensor itself has… | Medium | Engineer | View Guide |
| 51 | Climatic RF Communication Fault The wireless communication between the boiler and the Alpha Climatic remote control transmitter has failed.… | Low | DIY Check | View Guide |
| 6 | DHW Sensor Fault The domestic hot water temperature sensor has a wiring fault or has failed. Relevant on… | Medium | Engineer | View Guide |
| 60 | Pump Error (E-Tec / Evoke) On Alpha E-Tec and Evoke combi boilers, code 60 indicates the pump is stuck or… | High | Engineer | View Guide |
| 61 | Air in Pump / Restricted CH Flow (E-Tec / Evoke) On Alpha E-Tec and Evoke boilers, code 61 indicates air in the circulation pump or… | Medium | DIY Check | View Guide |
| 70 | Return/Flow Sensor Wiring Fault (E-Tec) On Alpha E-Tec boilers, code 70 indicates a wiring or connection issue with the return… | Medium | Engineer | View Guide |
| 71 | No Primary Temperature Rise Detected (E-Tec Regular) After ignition, the boiler has not detected a temperature rise in the primary circuit —… | High | Engineer | View Guide |
| 8 | Maximum Number of Resets Exceeded The boiler has reached its maximum reset count. Refer to the fault history codes to… | High | Engineer | View Guide |
| E01 | Ignition Failure The boiler has failed to ignite — the burner attempted to light but no flame… | Medium | DIY Check | View Guide |
| E02 | Flame Supervision Fault The flame supervision device has detected a problem. | High | Engineer | View Guide |
| E03 | Overheat Protection Activated The boiler exceeded maximum temperature. | High | Engineer | View Guide |
| E04 | High Limit Thermostat Tripped The high-limit (STB) safety thermostat has activated due to excessive temperature, cutting the gas supply. | High | Engineer | View Guide |
| E05 | Return Sensor Fault The return temperature sensor (NTC thermistor) has failed or has a wiring fault. | Medium | Engineer | View Guide |
| E06 | Flue Sensor Fault The flue gas temperature sensor is giving an out-of-range reading. | Medium | Engineer | View Guide |
| E07 | Overheat Sensor Tripped The main overheat safety sensor (STB) has activated due to excessive boiler temperature. | High | Engineer | View Guide |
| E08 | Flue Overheat Sensor Tripped The flue temperature sensor has detected dangerously high exhaust temperatures. | High | Engineer | View Guide |
| E09 | Fan Fault — No Air Pressure The fan has not generated sufficient air pressure for the air pressure switch to confirm… | High | Engineer | View Guide |
| E10 | Low Water Pressure The system water pressure has dropped below 0.6 bar — the minimum required for an… | Low | DIY Check | View Guide |
| E11 | Return Temperature Too High The return temperature from the heating circuit is higher than expected, indicating possible circulation issues. | Medium | Engineer | View Guide |
| E12 | DHW NTC Sensor Fault The hot water NTC sensor is faulty. | Medium | Engineer | View Guide |
| E13 | Outdoor Sensor Fault The outdoor temperature sensor is faulty. | Low | Engineer | View Guide |
| E14 | Pressure Sensor Fault The electronic water pressure sensor is faulty. | Medium | Engineer | View Guide |
| E15 | Low Gas Pressure The gas supply pressure at the boiler is below the minimum operating threshold. | High | Engineer | View Guide |
| E16 | Maximum Temperature Exceeded The boiler water temperature has exceeded its absolute maximum limit. | High | Engineer | View Guide |
| E17 | Gas Valve Fault The gas valve is not responding. | High | Engineer | View Guide |
| E18 | PCB Communication Error Internal PCB communication has failed. | High | Engineer | View Guide |
| E19 | Fan Fault The fan is not running correctly. | High | Engineer | View Guide |
| E20 | Flame Failure / No Flame Detected The boiler cannot detect a flame. The burner has failed to light or the ionisation… | Medium | Engineer | View Guide |
| E21 | Condensate Blocked The condensate drain is blocked or frozen. | Medium | DIY Check | View Guide |
| E22 | Flame Lost During Operation The flame was lost during running. | High | Engineer | View Guide |
| E23 | Low Gas Pressure Gas supply pressure is too low. | High | Engineer | View Guide |
| E24 | Air Pressure Switch Fault The APS is not detecting airflow. | High | Engineer | View Guide |
| E25 | Dry Fire / Low Water Detected The boiler has attempted to fire without detecting sufficient water flow, indicating very low water… | High | Engineer | View Guide |
| E26 | Diverter Valve Fault The diverter valve is stuck. | Medium | Engineer | View Guide |
| E27 | Rapid Temperature Rise Flow temperature rising too quickly. | High | Engineer | View Guide |
| E28 | Flue Fault There is a problem with the flue — it may be blocked, incorrectly installed, or… | High | Engineer | View Guide |
| E29 | Flow/Return Differential Fault Temperature gap between flow and return is abnormal. | Medium | Engineer | View Guide |
| E30 | Diverter Valve Fault The diverter valve (which switches flow between heating and hot water on a combi boiler)… | Medium | Engineer | View Guide |
| E31 | Pump Fault The pump is not running. | High | Engineer | View Guide |
| E32 | EEPROM Error PCB memory error. | High | Engineer | View Guide |
| E33 | PCB Internal Fault The PCB has detected an internal fault. | High | Engineer | View Guide |
| E34 | Overheat Lockout The boiler has reached an unsafe temperature and the overheat thermostat has triggered a lockout. | High | Engineer | View Guide |
| E35 | Frost Protection Active Frost protection is running. | Medium | DIY Check | View Guide |
| E36 | Flue Gas Overheat The flue gas temperature is too high. | High | Engineer | View Guide |
| E37 | eBUS Fault Communication bus error. | Medium | Engineer | View Guide |
| E38 | Mains Voltage Fault Mains voltage outside range. | Medium | Engineer | View Guide |
| E39 | Return NTC Short Circuit Return sensor wiring has shorted. | Medium | Engineer | View Guide |
| E40 | False Flame Detected An ionisation signal has been detected when no flame should be present. | High | Engineer | View Guide |
| E41 | Flow NTC Short Circuit Flow sensor wiring has shorted. | Medium | Engineer | View Guide |
| E42 | DHW NTC Short Circuit DHW sensor wiring has shorted. | Medium | Engineer | View Guide |
| E43 | Combustion Quality Fault Air/gas mixture outside limits. | High | Engineer | View Guide |
| E44 | Flame Detected After Shutdown Flame signal present with gas valve closed. | High | Engineer | View Guide |
| E45 | Coding Plug Fault Coding plug missing or unreadable. | High | Engineer | View Guide |
| E50 | DHW Sensor Fault The domestic hot water temperature sensor is giving an incorrect reading or has failed. | Medium | Engineer | View Guide |
| E55 | Flow Temperature Overheat The flow temperature is excessively high, causing a protective lockout. | High | Engineer | View Guide |
| E60 | Fan Fault The fan is not operating at the required speed or has stopped working. | High | Engineer | View Guide |
| E70 | Chip Card / Configuration Error The boiler's configuration chip card is not reading correctly or has not been properly installed. | Medium | Engineer | View Guide |
| E90 | Pressure Switch Fault The air pressure switch is not registering correctly — this switch confirms that the fan… | High | Engineer | View Guide |
| E96 | Gas Valve Fault The gas valve has an electronic fault and is not operating correctly. | High | Engineer | View Guide |
| SR | Service Reminder (E-Tec) Not a fault — this is a service reminder on Alpha E-Tec boilers, indicating the… | Low | DIY Check | View Guide |