Medium
30 on Alpha Cd50s Cd70s

Your boiler has detected that the water leaving it is significantly hotter than the water returning, suggesting a circulation problem in your heating system.

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/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.

DIY fix possible

Check that all radiator valves throughout your home are fully openEnsure your central heating pump is operating and not seizedCheck for any blockages or airlocks in your system that might be restricting flow

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Related fault codes

28View →

All 34 fault codes on the Cd50s Cd70s

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

000203040506071112131415161718192425262829313233363738446065114118FUSE

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