Select a fault code

Annual service interval reached.

No flame detected during the ignition sequence.

Safety thermostat has activated due to excessive temperature.

Flow temperature sensor has failed or is reading out of range.

Return pipe temperature sensor fault.

Boiler pressure has dropped below minimum operating level.

Fan not running or at incorrect speed.

Circulation pump fault detected.

Gas valve relay or control error.

Control board internal fault.

Failed to ignite. Heatline is discontinued — parts may be hard to source.

Condensate pipe is blocked or frozen.

Primary circuit overheated.

Repeated ignition failures — boiler has locked out.

Fan or air pressure switch fault.

Flow thermistor open circuit or short circuit.

System pressure too low for safe operation.