Your boiler has detected an internal electrical safety failure and has shut down to prevent damage or unsafe operation.

Safety relay open when should be closed

What causes this fault?

This fault occurs when the boiler's internal computer detects that a critical safety switch on the circuit board has failed to move into the correct position. The system shuts down immediately because it can no longer verify that the gas and ignition components are being controlled safely. The most common reason is that the electrical contacts on the main control board have worn out or become stuck over time.