How much does it cost to fix boiler error code GK90?

Typical repair cost for the boiler GK90 fault is £150-300 including labour.

GK90 High

Boiler Fault Code GK90

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code GK90 appears across 1 boiler brand and 1 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is failing to start up because the ignition system, which is responsible for lighting the fuel to produce heat, is not functioning correctly. (As reported on Grant Vortex)

Pick your boiler brand for the GK90 fix

Grant GK90 1 model

Source

Information for the GK90 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