How much does it cost to fix boiler error code On Off On Off * * On On?

Typical repair cost for the boiler On Off On Off * * On On fault is £100-220 including labour.

On Off On Off * * On On High

Boiler Fault Code On Off On Off * * On On

Also written as ONOFFONOFFONON — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code On Off On Off * * On On appears across 1 boiler brand and 1 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has shut down because it is unable to drain away the waste water it produces, causing a small internal reservoir to overflow. (As reported on Potterton Promax FSB 30HE)

Pick your boiler brand for the On Off On Off * * On On fix

Potterton On Off On Off * * On On 1 model

Source

Information for the On Off On Off * * On On fault code is sourced from the official service / installation manual for each model that displays it. Read more about how we source fault codes →

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026