Alpha
Fault Codes

Listed below are the common Alpha fault codes as described by the boiler manufacturer along with a possible cause.

Alpha Boiler Fault Codes

Fault CodeFaultPossible Cause
 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)
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)
 3 High flue thermostat temperature Blocked or restricted primary flow, heat exchanger air flow blocked, flue restriction, flue sensor fault
 4 Gas valve electrical connection fault Gas valve lead connection fault, faulty gas valve or faulty printed circuit board (PCB)
 5 Heating flow sensor fault Flow sensor wire connections, flow sensor faulty
 6 Domestic how water (DHW) sensor fault DHW sensor wiring connection or DHW sensor faulty
 8 Maximum number of resets Refer to fault history codes
 10 Primary system pressure low Check expansion vessel pressure (1 bar), leak in system, expansion relief valve operated or primary pressure switch
 12 Cylinder sensor fault (FlowSmart only) Cylinder sensor wiring connections or cylinder sensor faulty
 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
 16 Fan fault Fan wiring connections, fan fault or printed circuit board (PCB) fault
 20 Flame sensing fault Check flame sensing electrode and lead printed circuit board (PCB) fault
 24 Control panel button fault Jammed control panel or printed circuit board (PCB) buttons
 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
 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
 29 Flue sensor fault Sensor wiring connection or flue sensor faulty
 31 Loss of communication with external control (Alpha Climatic) Remote control or receiver connection wiring
 37 Low supply voltage Check mains power supply
 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
 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
 44 Safety lock out Check external control (room thermostat) requests and rapid on/off hot tap requests
 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
 47 Reduced burner output Air in heat exchanger, restricted primary flow, heat exchanger air flow blocked, flue restriction, flue sensor fault or pump fault
 51 Climatic RF communication fault Batteries need replacing, distance between boiler and climatic control too great, interference object blocking signal (metallic)

E-Tec, E-Tec Plus, Evoke Combi Boilers Error Codes

Fault CodeFaultPossible Cause
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.
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.
70 Return/flow sensor
Exchange from possible wiring fault
Issues with sensor wiring and connections.
Issues with sensor resistance.
75 / 76 Return/flow sensor fault from possible failure of one or both sensors
    Issues with sensor resistance.
SR Service reminder Service reminder countdown has reached 0 (this will not stop boiler from working) – boiler needs servicing.

Protec Plus Error Code

Fault CodeFaultPossible Cause
0A1 Ignition failure Issue with gas supply.
Ignition electrode position and spark issues.
0A2 Flame detection fault Flame sensing electrode connections.
A short circuit to the electrode or wires.
0A3 Overheat thermostat lock-out Flame sensing electrode connections.
A short circuit to the electrode or wires.
0A5 Fan speed fault Problem with flue /ventilation.
Issue with air inlet manifold and pipe.
Damage or fault with fan.
Fan wire connections.
0A7 High flue temperature fault Air in the primary heat exchanger.
System restrictions causing overheating.
Flue run may have restrictions or blockages.
0A8 Flame circuit fault Incorrect gas supply.
Ignition electrode position and spark.
Issues with flame sensing electrode gap and connections.
0A9 Gas valve electrical error Valve connection issues.
Main PCB.
Gas valve operation issues.
Gas contamination.
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.
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.
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.
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.
0A21 Main PCB fault Electrical connections.
Water ingress in connections.
0A30 Flow sensor short circuit Flow sensor connections and wires need checking.
Water ingress in connections.
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.
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.
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
0A43 Return sensor short circuit Problem with return sensor connections and wires.
Water ingress in connections
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.
0A80 Flow and return sensor connection fault (may occur after several minutes of boiler operation.) Wires are not connected to the correct sensors.
0E2 Flame sensing fault. Flame sensing electrode connections need checking.
Short circuit to the electrode or wire.
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
0E25 Main PCB fault All electrical connections need to be checked.
Water ingress in connections.
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
0E33 Low power supply voltage Electrical socket connection issues.
Problem with external power supply.
Possible power disruptions
0E37 Insufficient system pressure System needs checking for circulation and restrictions.
System pressure and gauge needs checking.
Pressure switch and connections need checking.
0E45 Flue sensor short circuit Flue sensor connections and wires need checking.
Water ingress in connections
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.
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
0E98 Flow and return sensor anomaly detected (sensor shows incorrect temperature value) M to O Connections need checking
Compatible software on PCB needs checking
0E99 Simple cascade communication error Wiring connections needs checking on all boilers.
Configuration, parameter 38.
FE94 Display PCB fault. Electrical connections to display board need checking.
Water ingress in connections.
Damage to buttons or LCD screen.
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
FE96 External sensor fault External sensor connections and wires need checking.
Water ingress in connections.
Boiler parameter settings are incorrect.
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

Alpha Flashing Light Errors Codes

Fault CodeFaultPossible Cause
 No lights on Electricity fault Check your electricity supply
 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
 Illuminated yellow B or C Burner is alight No action required
 Flashing red A or B Overheat thermostat has operated / Temperature sensor fault Rotate selector switch to the reset position (3) to reset
 Flashing yellow every 5 seconds or illuminated green D Electrical supply to the boiler is on No Action Required
 Flashing yellow B or flashing Red A Temperature sensor fault Contact a Heating Engineer
 Illuminated red A and flashing yellow B or Flashing red A and flashing red B Blocked flue or fan fault
 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
 Illuminated red A and flashing yellow B Pump fault or restricted flow
 Flashing red A and Flashing red B and flashing yellow C Temperature sensor wiring or flow and return connections incorrect
 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 E-Tec Regular Gas Boiler Error Codes

Fault CodeFaultPossible Cause
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.
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).
3 High flue thermostat temperature Blocked or restricted primary flow. Heat exchanger air flow blocked, flue restriction, flue sensor fault.
4 Gas valve electrical connection fault Gas valve lead connection fault. Faulty gas valve or faulty PCB.
5 Heating flow sensor fault Flow sensor wire connections. Flow sensor faulty.
6 Internal wiring error Incorrect wiring configuration detected. Internal wiring connections to PCB need checking.
7 Chimney sweep function is active Chimney sweep function is active. E07 is displayed on the climatic remote control.
8 Maximum number of resets Refer to fault history codes (INFO menud9)
12 Cylinder sensor fault (FlowSmart only) Cylinder sensor wiring connection – cylinder sensor faulty.
16 Fan fault Check fan wiring connection, fan fault or PCB fault.
20 Flame sensing fault Check flame sensing electrode and lead PCB for faults.
23 Heating return sensor fault Incorrect return sensor resistance value – return sensor wire connections or sensor could be faulty.
24 Control panel button fault Control panel button is stuck in the ‘on’ position – check for jammed control panel buttons or jammed PCB button.
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.
29 Flue sensor fault Check sensor wiring connection – flue sensor faulty.
31 Loss of communication with external control (Alpha Climatic) Remote control or receiver connection wiring.
37 Low supply voltage Check mains power supply.
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.
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.
44 Safety lockout Check external control (room thermostat) requests. Rapid on/off hot tap requests.
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.
46 Optional thermostat intervention No continuity of optional thermostat circuit – check the optional thermostat and cable are not damaged or wet.
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.
49 Return sensor high temperature intervention Return sensor has detected a high temperature on the exchanger return circuit.
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.
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.
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.