High
AL 09 on Sime Murelle Pro HE MkII Combi

Your boiler has detected that water is not moving through the system properly, which is preventing it from heating up safely.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

What the manual says

Manufacturer manual

No water circulating in the system — check pump rotation; verify pump not seized; check impeller; check filter

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 is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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