High
28 on Potterton Promax Combi 28 HE Plus

Your boiler has stopped working because its internal computer board is either the wrong version for this model or has been configured incorrectly.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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.

What the manual says

Manufacturer manual

Temperature sensors faulty or incorrect PCB fitted

From this model's manual
Verified against the Potterton Promax Combi He Plus installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This fault occurs when the boiler's main control board is unable to identify the specific model it is installed in. It most commonly happens after a repair where a new circuit board has been fitted but the specific software key has not been inserted, or if a technician has accidentally programmed the wrong settings into the system.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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