High
27 on Unical Alkon C 28 HE

Your boiler has detected an unexpected change in the flow of water through the system, usually caused by a circulation problem or a sticking pump.

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

ERROR Flow Gradient. Check if the pump switches off suddenly.

From this model's manual
Verified against the Unical/Unical Alkon C 28 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.

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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All 33 fault codes on the Alkon C 28 HE

Seeing a different code? Every code this model can display, in one place.

14568091112131415161718202122232426303233384344455355758081

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