How much does it cost to fix Potterton error code neon flashing (Section J)?

Typical repair cost for the Potterton neon flashing (Section J) fault is £120-250 including labour.

neon flashing (Section J) High

Potterton neon flashing (Section J) Fault Code

Q: What does the Potterton neon flashing (Section J) fault code mean?

Your boiler has switched itself off because it has detected an unsafe build-up of heat in either the water system or the exhaust flue.

Also written as NEONFLASHINGSECTIONJ — same fault.

The Potterton neon flashing (Section J) fault code means: your boiler has switched itself off because it has detected an unsafe build-up of heat in either the water system or the exhaust flue.. It appears on 2 Potterton models in our database.

Technical description: Safety thermostat or flue overheat thermostat operated

Typical repair cost £120-250 (including labour)

Engineer required

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

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

Potterton models that show the neon flashing (Section J) fault code

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

Source

Potterton neon flashing (Section J) 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