How much does it cost to fix boiler error code T8?

Typical repair cost for the boiler T8 fault is £150-350 including labour.

T8 High

Boiler Fault Code T8

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code T8 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 struggling to switch to its high-power mode because of an electrical signaling issue within its internal control system. (As reported on Ideal Falcon Gte)

Pick your boiler brand for the T8 fix

Ideal T8 1 model

Source

Information for the T8 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