Emergency
20 on Alpha E-Tec 33

Your boiler has detected heat or fire inside the unit even when it hasn't turned the gas on, so it has shut down to keep your home safe.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

What the manual says

Manufacturer manual

Flame sensing fault - False flame detection / Flame detected but gas valve is not open

From this model's manual
Verified against the Alpha E Tec Regular installation & service manual, page 46.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

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

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