Select a fault code

The fan is not reaching or is exceeding the required speed for safe combustion.

The relay controlling the gas valve on the PCB has detected a fault.

The system pressure has dropped below the minimum required level (usually below 0.5 bar).

The flow temperature sensor has detected a fault or is reading an abnormal temperature.

The return temperature sensor is reading outside normal range or has failed.

The domestic hot water temperature sensor has failed or is reading incorrectly.

The boiler has reached an unsafe temperature and the high limit thermostat has cut out.

The safety temperature limiter has tripped — boiler overheated beyond safe limits.

The boiler attempted to ignite but failed to establish a flame.

The boiler is detecting a flame signal when no ignition has been requested — ghost flame.