Boiler Fault Code F (High system water pressure)

Also written as FHIGHSYSTEMWATERPRESSURE — same fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026

Fault code F (High system water pressure) 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's internal water pressure is currently too high, which means it has automatically shut down to prevent damage to the system. (As reported on Saunier Duval Thema F 30 E Plus)