How much does it cost to fix boiler error code F09?

Typical repair cost for the boiler F09 fault is £90-160 including labour.

F09 High

Boiler Fault Code F09

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 31 August 2026

Fault code F09 appears across 3 boiler brands and 5 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 lost track of the temperature of the water coming back from your radiators, causing the system to stop working for safety. (As reported on Heatline Vizo Plus)

Pick your boiler brand for the F09 fix

Ferroli F09 3 models Heatline F09 1 model Viessmann F09 1 model

Source

Information for the F09 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 31 August 2026