BoilerFaultCodes Error 133 High
Boiler Fault Code Error 133
Also written as ERROR133 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Error 133 appears across 1 boiler brand and 2 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler is trying to ignite but cannot detect a flame, likely due to a gas supply issue or a blockage in the combustion process. (As reported on Potterton Titanium)
Pick your boiler brand for the Error 133 fix
Source
Information for the Error 133 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