High
A (number) on Potterton Powermax HE

Your boiler has detected a safety concern or internal failure and has shut itself down to prevent damage.

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

Operating errors or fault lock-out conditions are displayed as A (number) - see chart on Page 7.

From this model's manual
Verified against the Potterton Powermax He 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 internal sensors detect that the burner has failed to light or maintain a flame safely. The most common reasons include a lack of gas reaching the burner, a worn-out ignition spark, or the control board losing track of the combustion process.

This issue is more frequent during the first cold snap of winter when components that have sat idle all summer are suddenly forced to work under high demand.

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.

Find a Gas Safe engineer
Search the official register →

Avoid the next call-out bill

A cover plan would handle faults like A (number): no call-out fees, no surprise bills.

Approved partner
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Get a quote →

Affiliate links. We may earn a commission at no extra cost to you.

Related fault codes

Related guides you might find useful