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

Typical repair cost for the boiler Er 99 fault is £80-160 including labour.

Er 99 High

Boiler Fault Code Er 99

Also written as ER99 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code Er 99 appears across 2 boiler brands and 3 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler’s internal computer has forgotten which model it is, meaning it has lost its configuration settings and cannot operate. (As reported on Biasi Inovia 2020)

Pick your boiler brand for the Er 99 fix

Biasi Er 99 2 models Johnson Starley Er 99 1 model

Source

Information for the Er 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 27 April 2026