High
d12 on Alpha Evoke 10 / 18

Your boiler is reporting an issue with the water circulation pump speed, which is preventing it from effectively moving heat around your home.

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

Pump speed (0 = OFF, 1,2,3,4,5,6,7,8,9)

From this model's manual
Verified against the Alpha Evoke installation & service manual, page 30.
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 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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Related fault codes

d11View →d13View →

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