Select a fault code

The boiler has failed to ignite. This is typically caused by low gas pressure, a faulty ignition electrode, or a blocked condensate pipe in cold weather.

The flame went out unexpectedly during normal operation. Brief gas supply interruptions or pressure fluctuations can cause this.

The boiler has reached an unsafe temperature and the overheat thermostat has cut it out. Causes include a blocked heat exchanger, poor circulation, or a failing pump.

A temperature sensor (NTC thermistor) has failed or is reading outside normal parameters.

The fan is not operating correctly or there is a problem with the flue system.

A fault has been detected on the gas valve. The boiler cannot safely control gas flow.

The main circuit board has detected an internal fault.

The system water pressure has dropped below the minimum operating level.

The air pressure switch has not confirmed correct fan operation. This switch prevents ignition if the fan is not running.

The flame detection circuit is detecting a flame when the burner should be off. This is a serious fault.

The pump has failed or is not circulating water correctly.

The condensate drain is blocked, often due to freezing in cold weather.