Alpha Fault Codes

Comprehensive reference table of all Alpha boiler error codes. Click any code for detailed troubleshooting steps.

Pro Tip

Check your boiler's digital display panel (usually behind a drop-down cover) to find the current active fault code.

Error CodeDescription
1 / E01 / 0A1Ignition failure; check gas supply, pressure tubes, and flame sensor.
2 / 0A3Overheat lockout; blocked heat exchanger, pump failure, or tripped thermal fuse.
10 / E10Low primary system water pressure; requires manual re-pressurisation.
60Pump error; pump is physically stuck or experiencing an electrical fault.
61Air in pump / restricted central heating flow; check valves and system purge.
3High flue thermostat temperature; restricted primary flow or blocked exchanger.
4Gas valve electrical fault; wiring connections to the PCB.
0A5Fan speed fault; issue with flue/ventilation or fan wiring connections.
47 / E47Exhaust thermostat intervention; flue gas temperatures have exceeded limits.
70Return/flow sensor fault; possible wiring fault or incorrect resistance.
0A31Flow sensor out of range; sensor detecting temperature outside normal parameters.
5Heating flow sensor fault; wiring issue or sensor failure.
16Fan fault; fan wiring connections or PCB fault.
20Flame sensing fault; check flame sensing electrode and lead.
25Overheat lockout; caused by air in the heat exchanger or restricted flow.
0A9Gas valve electrical error; main PCB or valve connection issues.
0A43Return sensor short circuit; water ingress in connections or damaged wire.
0E33Low power supply voltage; electrical socket connection issues or power disruption.

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