Medium
45 on Alpha Intec2 30SE

Your boiler has detected that the water is not circulating efficiently through your heating system, as it is coming back to the boiler much cooler than it left.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

A too high ΔT between CH flow and return sensors has been detected

From this model's manual
Verified against the Alpha Intec2 25 28xe 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 fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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