How much does it cost to fix boiler error code F86?

Typical repair cost for the boiler F86 fault is £90-180 including labour.

F86 Medium

Boiler Fault Code F86

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code F86 appears across 2 boiler brands and 8 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 problem with the safety connection for your underfloor heating system, which usually means a sensor is loose or has shut the system down to prevent floor damage. (As reported on Heatline CaprizPlus 24a)

Pick your boiler brand for the F86 fix

Glow-worm F86 1 model Heatline F86 7 models

Source

Information for the F86 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