High
13 on Glow-worm 30ci Plus

Your boiler's internal computer has developed a fault and can no longer control the heating system safely.

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

Main board fault

From this model's manual
Verified against the Glow Worm 30ci Plus installation & service manual, page 39.
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 central control unit suffers an internal electrical failure or memory error. It is typically caused by ageing capacitors on the circuit board or sudden electrical surges that damage the delicate microprocessors. Because the 'brain' of the boiler can no longer communicate with the sensors and gas valve, the unit shuts down to prevent unsafe operation.

This fault is slightly more common during winter months when the boiler is working under high demand or following heavy thunderstorms which can cause electrical spikes in the local grid.

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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