BoilerFaultCodesPotterton 9 (Flashing) Fault Code
Also written as 9FLASHING — same fault.
The Potterton 9 (Flashing) fault code means: your boiler has shut itself down for safety because it failed to light or detected an internal problem.. It appears on 1 Potterton model in our database.
Technical description: Boiler at lock-out
What causes the Potterton 9 (Flashing) fault?
This fault occurs when the boiler has tried to ignite several times but failed to establish a stable flame. The most common reason is a lack of fuel reaching the burner, often due to a faulty gas valve or worn-out ignition sparks that can no longer light the gas safely.
DIY fix possible
Locate the reset button on the front control panel.Press and hold the reset button for several seconds.Check if your gas supply is active by testing another gas appliance like a hob.
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Gas Safe Register →Potterton models that show the 9 (Flashing) fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Potterton 9 (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