| Faultcode | Fault | Possible Cause | Model Specific |
|---|---|---|---|
| 1 | Ignition failure | Gas supply, pressure tubes, ignition electrode, flame sensor electrode, ignition generator, lead flame sensor, electrode lead, gas valve setting, gas valve printed circuit board (PCB) | Alpha Boiler |
| 2 | Overheat boiler lock out | Pump or flow problem, blocked heat exchanger, air in heat exchanger, overheat thermostat, thermal fuse (if open circuit then replace primary heat exchanger) | Alpha Boiler |
| 3 | High flue thermostat temperature | Blocked or restricted primary flow, heat exchanger air flow blocked, flue restriction, flue sensor fault | Alpha Boiler |
| 4 | Gas valve electrical connection fault | Gas valve lead connection fault, faulty gas valve or faulty printed circuit board (PCB) | Alpha Boiler |
| 5 | Heating flow sensor fault | Flow sensor wire connections, flow sensor faulty | Alpha Boiler |
| 6 | Domestic how water (DHW) sensor fault | DHW sensor wiring connection or DHW sensor faulty | Alpha Boiler |
| 8 | Maximum number of resets | Refer to fault history codes | Alpha Boiler |
| 10 | Primary system pressure low | Check expansion vessel pressure (1 bar), leak in system, expansion relief valve operated or primary pressure switch | Alpha Boiler |
| 12 | Cylinder sensor fault (FlowSmart only) | Cylinder sensor wiring connections or cylinder sensor faulty | Alpha Boiler |
| 15 | Internal wiring error | Check internal wiring connections to printed circuit board (PCB), Combi boiler domestic hot water (DHW) sensor X4, System boiler link X14 | Alpha Boiler |
| 16 | Fan fault | Fan wiring connections, fan fault or printed circuit board (PCB) fault | Alpha Boiler |
| 20 | Flame sensing fault | Check flame sensing electrode and lead printed circuit board (PCB) fault | Alpha Boiler |
| 24 | Control panel button fault | Jammed control panel or printed circuit board (PCB) buttons | Alpha Boiler |
| 25 | Overheat lock out | Air in heat exchanger, blocked or restricted primary flow, heat exchanger air flow blocked, flue restriction, flue sensor fault, pump fault, boiler or heating circuit valve closed | Alpha Boiler |
| 27 | Insufficient primary flow | Blocked or restricted primary flow, air in heat exchanger, boiler or heating circuit valve closed, pump fault or primary flow sensor fault | Alpha Boiler |
| 29 | Flue sensor fault | Sensor wiring connection or flue sensor faulty | Alpha Boiler |
| 31 | Loss of communication with external control (Alpha Climatic) | Remote control or receiver connection wiring | Alpha Boiler |
| 37 | Low supply voltage | Check mains power supply | Alpha Boiler |
| 38 | Loss of flame rectification | Flame sensing electrode and lead, check flue gas recirculation, check the gas valve settings and check the fan speed settings | Alpha Boiler |
| 43 | Loss of flame rectification | Check gas supply working, check flame sensing electrode and lead, check for flue gas recirculation, check the gas valve settings, check the fan speed settings | Alpha Boiler |
| 44 | Safety lock out | Check external control (room thermostat) requests and rapid on/off hot tap requests | Alpha Boiler |
| 46 | External sensor intervention | External sensor and cable damaged or wet, continuity of external sensor and circuit, check connection at X19 on printed circuit board (PCB) and sensor connecting block | Alpha Boiler |
| 47 | Reduced burner output | Air in heat exchanger, restricted primary flow, heat exchanger air flow blocked, flue restriction, flue sensor fault or pump fault | Alpha Boiler |
| 51 | Climatic RF communication fault | Batteries need replacing, distance between boiler and climatic control too great, interference object blocking signal (metallic) | Alpha Boiler |
| 60 | Pump error (stuck or there is an electrical pump fault) | Pump operation (may need to free the pump shaft), issue with pump wiring or pump replacement needed. | E-Tec, E-Tec Plus, Evoke Combi |
| 61 | Air in the pump (restricted central heating flow) | Flow and Return valves may not be open, iIncorrect system pressure, system not purged properly or flow return valves are open. | E-Tec, E-Tec Plus, Evoke Combi |
| 70 | Return/flow sensor, Exchange from possible wiring fault | Issues with sensor resistance. | E-Tec, E-Tec Plus, Evoke Combi |
| 75 / 76 | Return/flow sensor fault from possible failure of one or both sensors | Issues with sensor resistance. | E-Tec, E-Tec Plus, Evoke Combi |
| SR | Service reminder | Service reminder countdown has reached 0 (this will not stop boiler from working) _ boiler needs servicing. | E-Tec, E-Tec Plus, Evoke Combi |
| 0A1 | Ignition failure | Issue with gas supply. Ignition electrode position and spark issues. | Protec Plus |
| 0A2 | Flame detection fault | Flame sensing electrode connections. A short circuit to the electrode or wires. | Protec Plus |
| 0A3 | Overheat thermostat lock-out | Flame sensing electrode connections. A short circuit to the electrode or wires. | Protec Plus |
| 0A5 | Fan speed fault | Problem with flue /ventilation. Issue with air inlet manifold and pipe. Damage or fault with fan. Fan wire connections | Protec Plus |
| 0A7 | High flue temperature fault | Air in the primary heat exchanger. System restrictions causing overheating. Flue run may have restrictions or blockages. | Protec Plus |
| 0A8 | Flame circuit fault | Incorrect gas supply. Ignition electrode position and spark. Issues with flame sensing electrode gap and connections. | Protec Plus |
| 0A9 | Gas valve electrical error | Valve connection issues. Main PCB. Gas valve operation issues. Gas contamination. | Protec Plus |
| 0A15 | Flow and return sensor anomaly detected. (incorrect temperature value shown on sensor.) | Poor or incorrect circulation. External circuit influences. Problem with resistances of flow and return sensors | Protec Plus |
| 0A16 | Flow sensor temperature rise incorrect (time taken for flow temperature to rise is too long. | System circulation issues. System volume or flow is too high. Boiler output is insufficient for the system. | Protec Plus |
| 0A17 | Return sensor temperature rise incorrect (time taken for flow temperature to rise is too long. | System circulation issues. System volume or flow is too high. Boiler output is insufficient for the system. | Protec Plus |
| 0A18 | Flow and return sensor anomaly detected. Sudden temperature change detected on the flow or return sensor. | System circulation issues. Problem with operation of zone valves. Resistances and function of flow and return sensors needs checking. | Protec Plus |
| 0A21 | Main PCB fault | Electrical connections. Water ingress in connections. | Protec Plus |
| 0A30 | Flow sensor short circuit | Flow sensor connections and wires need checking. Water ingress in connections. | Protec Plus |
| 0A31 | Flow sensor out of range. (sensor measures a temperature not in normal range.) | Problem with flow sensor connections and damaged wires. Sensor resistance values wrong. | Protec Plus |
| 0A37 – Pro Tec 50 | Insufficient system flow (if the system flow is too low for a certain length of time boiler will switch off) | Flow switch reading needs checking. Restrictions or shut valves in system. Pump function issues. System pressure issues. | Protec Plus |
| 0A37 – Pro tec 70, 90, 115 | Insufficient system pressure (if the system pressure is too low the boiler switches off.) | System pressure needs to be 1 – 2 bar if its not the pressure needs refilling to the correct amount | Protec Plus |
| 0A43 | Return sensor short circuit | Problem with return sensor connections and wires. Water ingress in connections | Protec Plus |
| 0A44 | Return sensor out of range. Sensor measures a temperature outside normal working range | Return sensor connections and damaged wires. Return sensor resistance values need checking. | Protec Plus |
| 0A80 | Flow and return sensor connection fault (may occur after several minutes of boiler operation.) | Wires are not connected to the correct sensors. | Protec Plus |
| 0E2 | Flame sensing fault. | Flame sensing electrode connections need checking. Short circuit to the electrode or wire. | Protec Plus |
| 0E13 | Maximum number of resets reached. (Over 5 reset attempts have been reached within 15 minutes.) | Investigate initial fault code displayed. Power supply needs to be turned Off/On to clear this code | Protec Plus |
| 0E25 | Main PCB fault | All electrical connections need to be checked. Water ingress in connections. | Protec Plus |
| 0E34 | DHW sensor out of range (measures a temperature outside normal working range.) | DHW sensor connections and damaged cables. Issues with DHW sensor resistance values | Protec Plus |
| 0E33 | Low power supply voltage | Electrical socket connection issues. Problem with external power supply. Possible power disruptions | Protec Plus |
| 0E37 | Insufficient system pressure | System needs checking for circulation and restrictions. System pressure and gauge needs checking. Pressure switch and connections need checking. | Protec Plus |
| 0E45 | Flue sensor short circuit | Flue sensor connections and wires need checking. Water ingress in connections | Protec Plus |
| 0E46 | Flue sensor out of range (measures a temperature outside of normal working range) | Flue sensor connections, wires and flue sensor resistance values need checking. | Protec Plus |
| 0E81 | Flow and return sensor anomaly detected (the sensor shows an incorrect temperature value) | Poor or incorrect circulation / external circuit influences resistance of flow return sensors need checking | Protec Plus |
| 0E98 | Flow and return sensor anomaly detected (sensor shows incorrect temperature value) | M to O Connections need checking Compatible software on PCB needs checking | Protec Plus |
| 0E99 | Simple cascade communication error | Wiring connections needs checking on all boilers. Configuration, parameter 38. | Protec Plus |
| FE94 | Display PCB fault. | Electrical connections to display board need checking. Water ingress in connections. Damage to buttons or LCD screen. | Protec Plus |
| FE95 | External flow sensor out of range or short circuit/ External flow sensor measures a temperature outside of normal working range. | External flow sensor connections and wires need checking for damage. External flow sensor resistance values need checking to make sure they are between 5 and 0 | Protec Plus |
| FE96 | External sensor fault | External sensor connections and wires need checking. Water ingress in connections. Boiler parameter settings are incorrect | Protec Plus |
| FE97 | Boiler PCB configuration error (may occur if the main PCB or display PCB is changed.) | All electrical connections. Incorrect parameter settings on PCB. Press ‘-‘ CH button until ‘AUTO’ appears, then press and hold ‘RESET’ button until ‘bu1’ appears | Protec Plus |
| No lights on | Electricity fault | Check your electricity supply | Alpha Flashing |
| Illuminated red A or B | Burner has failed to light | Rotate selector switch to the reset position (3) and the ignition sequence will restart after a delay of about 30 seconds | Alpha Flashing |
| Illuminated yellow B or C | Burner is alight | No action required | Alpha Flashing |
| Flashing red A or B | Overheat thermostat has operated / Temperature sensor fault | Rotate selector switch to the reset position (3) to reset | Alpha Flashing |
| Flashing yellow every 5 seconds or illuminated green D | Electrical supply to the boiler is on | No Action Required | Alpha Flashing |
| Flashing yellow B or flashing Red A | Temperature sensor fault | Contact a heating engineer | Alpha Flashing |
| Illuminated red A and flashing yellow B or Flashing red A and flashing red B | Blocked flue or fan fault | Alpha Flashing | |
| Flashing yellow or flashing Red A or Flashing (alternating) red A and flashing (alternating) yellow B | System pressure is very low and re-pressurisation is required | Alpha Flashing | |
| Illuminated red A and flashing yellow B | Pump fault or restricted flow | Alpha Flashing | |
| Flashing red A and Flashing red B and flashing yellow C | Temperature sensor wiring or flow and return connections incorrect | Alpha Flashing | |
| Flashing red A and flashing red B and flashing yellow C indicators | Flue temperature too high (air in the heat exchanger, heat exchanger blocked | Alpha Flashing | |
| 1 | Ignition failure | Check the gas supply, pressure tubes, ignition electrode, flame sensor electrode, ignition generator or lead flame sensor, gas valve setting and PCB. | Alpha E-Tec Regular |
| 2 | Overheat boiler lockout | Pump or flow problem. Caused by a blocked heat exchanger, air in heat exchanger, overheated thermostat, thermal fuse (if open circuit then replace primary heat exchanger). | Alpha E-Tec Regular |
| 3 | High flue thermostat temperature | Blocked or restricted primary flow. Heat exchanger air flow blocked, flue restriction, flue sensor fault. | Alpha E-Tec Regular |
| 4 | Gas valve electrical connection fault | Gas valve lead connection fault. Faulty gas valve or faulty PCB. | Alpha E-Tec Regular |
| 5 | Heating flow sensor fault | Flow sensor wire connections. Flow sensor faulty. | Alpha E-Tec Regular |
| 6 | Internal wiring error | Incorrect wiring configuration detected. Internal wiring connections to PCB need checking. | Alpha E-Tec Regular |
| 7 | Chimney sweep function is active | Chimney sweep function is active. E07 is displayed on the climatic remote control. | Alpha E-Tec Regular |
| 8 | Maximum number of resets | Refer to fault history codes (INFO menud9) | Alpha E-Tec Regular |
| 12 | Cylinder sensor fault (FlowSmart only) | Cylinder sensor wiring connection _ cylinder sensor faulty. | Alpha E-Tec Regular |
| 16 | Fan fault | Check fan wiring connection, fan fault or PCB fault. | Alpha E-Tec Regular |
| 20 | Flame sensing fault | Check flame sensing electrode and lead PCB for faults. | Alpha E-Tec Regular |
| 23 | Heating return sensor fault | Incorrect return sensor resistance value _ return sensor wire connections or sensor could be faulty. | Alpha E-Tec Regular |
| 24 | Control panel button fault | Control panel button is stuck in the ïonÍ position _ check for jammed control panel buttons or jammed PCB button. | Alpha E-Tec Regular |
| 27 | Insufficient primary flow | Blocked or restricted primary flow. Air in heat exchanger, boiler or heating circuit valve closed, pump fault or primary flow sensor fault. | Alpha E-Tec Regular |
| 29 | Flue sensor fault | Check sensor wiring connection _ flue sensor faulty. | Alpha E-Tec Regular |
| 31 | Loss of communication with external control (Alpha Climatic) | Remote control or receiver connection wiring. | Alpha E-Tec Regular |
| 37 | Low supply voltage | Check mains power supply. | Alpha E-Tec Regular |
| 38 | Loss of flame rectification | Check flame sensing electrode and lead and for flue gas recirculation. Check or adjust the gas valve settings. Check or adjust the fan speed settings. | Alpha E-Tec Regular |
| 43 | Loss of flame rectification | Check gas supply/working pressure, flame sensing electrode and lead, check for flue gas recirculation, check/adjust the gas valve settings, check/adjust the fan speed settings. | Alpha E-Tec Regular |
| 44 | Safety lockout | Check external control (room thermostat) requests. Rapid on/off hot tap requests. | Alpha E-Tec Regular |
| 45 | High-temperature difference | The boiler is detecting an unexpected increase between the system flow and return sensors. Boiler output is limited for boiler protection and once restored the boiler resumes regular operation. | Alpha E-Tec Regular |
| 46 | Optional thermostat intervention | No continuity of optional thermostat circuit _ check the optional thermostat and cable are not damaged or wet. | Alpha E-Tec Regular |
| 47 | Reduced burner output | Flue thermostat has sensed high flue gas temperature and reduced the burner output to prevent damage. If the temperature continues to rise the boiler will lockout and the E03 error code will be displayed. This could be due to air in the heat exchanger, restricted primary flow or heat exchanger air blocked. | Alpha E-Tec Regular |
| 49 | Return sensor high temperature intervention | Return sensor has detected a high temperature on the exchanger return circuit. | Alpha E-Tec Regular |
| 51 | Climatic RF communication fault | The error between the communication of the climatic transmitter and boiler receiver. Could mean the batteries need replacing or the distance between the boiler and climatic control is too great or a metal object is blocking the signal. | Alpha E-Tec Regular |
| 70 | Return flow sensor error | Possible wiring faults sensor is incorrectly fitted or the system is blocked _ check the sensor wiring and connections, also check sensor resistance and circulation. | Alpha E-Tec Regular |
| 71 | No primary temperature increase detected | From ignition the boiler detects no temperature rise in the primary circuit _ check system filling and venting, air locks preventing flow check, blocked flow or closed valves. | Alpha E-Tec Regular |
Gas work stays with a Gas Safe registered engineer. Some codes only apply to a named range — check the model column.