neon flashing (3rd instance) High

Potterton neon flashing (3rd instance) Fault Code

Also written as NEONFLASHING3RDINSTANCE — same fault.

The Potterton neon flashing (3rd instance) fault code means: your boiler is struggling to confirm it is venting exhaust gases safely, causing the internal fan to run continuously at high speed to try and clear the system.. It appears on 1 Potterton model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Fan runs at max speed. Air pressure switch proved. Go to section ‘D’.
Typical repair cost £150-300 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Potterton models that show the neon flashing (3rd instance) fault code

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

Source

Potterton neon flashing (3rd instance) 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