F Low

Gledhill F Fault Code

The Gledhill F fault code means: your boiler has detected that the water temperature is too low and has automatically turned on its internal heater to prevent the pipes from freezing.. It appears on 1 Gledhill model in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Constant - Frost protection Level 1
Typical repair cost £0 (including labour)

DIY fix possible

Ensure the boiler's power supply remains switched onCheck that the property's main heating controls (thermostat) are turned up slightlyEnsure any radiators in cold areas are not completely turned offWait for the boiler to finish its warming cycle, at which point the 'F' code will disappear

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Gledhill models that show the F fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Gledhill 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