High
Neon A flashing on Alpha CD28

Your boiler has lost the ability to accurately measure its internal temperature, so it has safely shut down to prevent overheating.

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.

Technical description

Primary or DHW temperature sensor faulty

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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