BoilerFaultCodesPotterton Preheat control neon flashing Fault Code
Also written as PREHEATCONTROLNEONFLASHING — same fault.
The Potterton Preheat control neon flashing fault code means: your boiler has detected an internal communication error or a disconnected jumper wire, which usually prevents the preheat function or the boiler from operating correctly.. It appears on 1 Potterton model in our database.
Technical description: Go to section ‘L’: Check continuity of loop on A10 connector.
What causes the Potterton Preheat control neon flashing fault?
This fault occurs when the boiler's main control board loses its connection to a specific internal bypass wire that tells it how to manage the preheat function. It is usually caused by a loose connection at the 'A10' plug or a physical break in the wiring harness, which prevents the boiler from completing its safety checks. In some cases, the internal electronics on the printed circuit board may have failed, meaning it can no longer 'see' the loop even if the wire is intact.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Potterton models that show the Preheat control neon flashing fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Potterton Preheat control neon 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