Medium
AL 04 on Sime Murelle Pro HE MkII Combi

Your boiler's temperature sensor for hot water has stopped working properly, which means you might not get any hot water or it may be inconsistent.

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

Domestic hot water sensor (SS) fault — combi models; check wiring connections; replace sensor if open/short circuit

From this model's manual
Verified against the Sime Murelle Pro He Combi installation & service manual, page 32.
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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