How much does it cost to fix boiler error code 91?

Typical repair cost for the boiler 91 fault is £80-160 including labour.

91 Medium

Boiler Fault Code 91

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code 91 appears across 3 boiler brands and 17 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has detected a temporary service issue that is preventing it from completing its ignition sequence, though it may resolve itself or require a simple reset. (As reported on Vokera Linea HE)

Pick your boiler brand for the 91 fix

Alpha 91 10 models Biasi 91 4 models Vokera 91 3 models

Source

Information for the 91 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