Flashing Mains ON light Low

Potterton Flashing Mains ON light Fault Code

Also written as FLASHINGMAINSONLIGHT — same fault.

The Potterton Flashing Mains ON light fault code means: your boiler is receiving power, but it has been turned off at the main control dial.. It appears on 1 Potterton 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: Indicates that there is a mains electrical supply to the boiler, but the control knob is in the OFF position.

DIY fix possible

Locate the main control dial on the front of the boiler panelTurn the dial clockwise away from the 'OFF' or '0' position to your desired heating or hot water setting

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Potterton models that show the Flashing Mains ON light fault code

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

Source

Potterton Flashing Mains ON light 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 7 July 2026