High
ALL09 on Sime iQE Simplicity 20T

Your boiler has stopped working because water is not flowing through the system correctly.

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

if the boiler detects inadequate system water circulation, the boiler will stop and display AL 09. Ensure that at least one radiator is turned on and that all isolation valves are open, if problem persists it could be due to a blocked filter within the boiler, seek help and advice from a qualified engineer.

From this model's manual
Verified against the Sime Iqe Simplicity 20t installation & service manual, page 8.
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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