Medium
30 on Alpha SY9 24

Your boiler has detected that your heating pipes are not transferring heat effectively, usually caused by a blockage in the system or the pump struggling to move water around.

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

Temperature difference between system flow and return too high

From this model's manual
Verified against the Alpha Cd50s Cd70s 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 fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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