High Lockout
E109 on Baxi EcoBlue Advance

Your boiler is struggling to move heated water through the system, causing it to shut down to prevent overheating.

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.

Technical description

Poor circulation

What causes this fault?

This fault occurs when the water inside your boiler gets too hot too quickly because it isn't being pushed around your radiators fast enough. The most common reasons are a pump that has seized up or a build-up of sludge and debris that is physically blocking the pipework. Because the heat has nowhere to go, the boiler forces a shutdown to protect its internal components from heat damage.

This issue often surfaces in autumn when the heating is turned back on for the first time, as internal pump parts can seize up after sitting idle during the summer months.

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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