How much does it cost to fix boiler error code 99?

Typical repair cost for the boiler 99 fault is £150-300 including labour.

99 High

Boiler Fault Code 99

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code 99 appears across 4 boiler brands and 14 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 general internal fault that is preventing it from operating, which usually indicates an electronic control board or communication issue. (As reported on Alpha E-Tec Plus 28)

Pick your boiler brand for the 99 fix

Alpha 99 6 models Biasi 99 2 models ECA 99 1 model Johnson Starley 99 5 models

Source

Information for the 99 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 7 July 2026