BoilerFaultCodesPotterton F (Flashing) Fault Code
Also written as FFLASHING — same fault.
The Potterton F (Flashing) fault code means: your boiler has stopped working and entered a safety shutdown mode, meaning it will not provide heating or hot water until it is reset or repaired.. It appears on 2 Potterton models in our database.
Technical description: Boiler at Lock-Out
What causes the Potterton F (Flashing) fault?
This fault occurs when the boiler has tried to ignite several times but failed to detect a stable flame, leading the system to shut down for safety. The most common reasons are a lack of gas reaching the burner or a worn-out component failing to spark or sense the flame correctly. It essentially means the boiler’s internal computer has lost confidence that it can burn fuel safely.
This fault can be more frequent during the first cold snap of autumn when internal components that have been sitting idle all summer are suddenly stressed or seized.
DIY fix possible
Locate the reset button or control knob on the front panelTurn the knob to the 'Reset' position or press the reset button for 5 secondsWait for the boiler to attempt to restart; if the code returns, contact a professional
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Gas Safe Register →Potterton models that show the F (Flashing) fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Potterton F (Flashing) fault code information on this page is sourced and cross-checked against the official Potterton service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026