How much does it cost to fix boiler error code 1A, 1B?

Typical repair cost for the boiler 1A, 1B fault is £120-£350 including labour.

1A, 1B High

Boiler Fault Code 1A, 1B

Also written as 1A1B — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code 1A, 1B appears across 1 boiler brand and 5 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler's burner has shut down because it isn't receiving enough air or fuel to ignite safely, meaning you will have no heating or hot water until it is fixed. (As reported on Viessmann A8)

Pick your boiler brand for the 1A, 1B fix

Viessmann 1A, 1B 5 models

Source

Information for the 1A, 1B 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