How much does it cost to fix Potterton error code On On On?

Typical repair cost for the Potterton On On On fault is £120-250 including labour.

On On On High

Potterton On On On Fault Code

Q: What does the Potterton On On On fault code mean?

Your boiler has lost its internal electrical connection, meaning it cannot receive the signals needed to operate and will currently have no heating or hot water.

Also written as ONONON — same fault.

The Potterton On On On fault code means: your boiler has lost its internal electrical connection, meaning it cannot receive the signals needed to operate and will currently have no heating or hot water.. It appears on 4 Potterton models in our database.

Technical description: LV Wiring Harness. Ensure 8-way PCB connector securely pushed in. If fault persists replace LV wiring harness.

Typical repair cost £120-250 (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 On On On fault code

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

Source

Potterton On On On 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