How much does it cost to fix boiler error code F28?

Typical repair cost for the boiler F28 fault is £120-250 including labour.

F28 High

Boiler Fault Code F28

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code F28 appears across 3 boiler brands and 19 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 that its temperature sensors are giving conflicting readings, which has caused it to stop working for safety. (As reported on Saunier Duval Isotwin F30E)

Pick your boiler brand for the F28 fix

Glow-worm F28 9 models Heatline F28 8 models Saunier Duval F28 2 models

Source

Information for the F28 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