BoilerFaultCodesGledhill FLASHING F Fault Code
Also written as FLASHINGF — same fault.
The Gledhill FLASHING F fault code means: your boiler has detected very cold temperatures and has automatically turned on its high-level frost protection mode to prevent the internal pipes from freezing.. It appears on 1 Gledhill model in our database.
Technical description: Frost Protection active - Level 2
DIY fix possible
Ensure the boiler's power remains switched onOpen any radiator valves in cold areas of the home to allow warm water to circulateCheck that the condensate pipe outside is not frozen or blockedWait for the boiler to finish its heating cycle, after which the code should disappear automatically
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Gledhill models that show the FLASHING F fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Gledhill FLASHING F fault code information on this page is sourced and cross-checked against the official Gledhill service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026