Medium
37 on Alpha Cd50s Cd70s

Your boiler is struggling to read the temperature of the water coming back into the system, which is preventing it from heating your home properly.

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

System return sensor fault (open)

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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