High
ON FLASH FLASH on Baxi Solo

Your boiler has detected that water is not moving through the system properly or there isn't enough water inside the unit to safely heat up.

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

Circulation error or dry fire

Shared across the range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This fault occurs when the boiler's internal sensors detect that heat isn't being carried away from the heat exchanger quickly enough, usually due to a lack of water flow. The most common reasons are a failed circulation pump that can no longer push water through the radiators, or a blockage such as a build-up of sludge or air in the pipework.

This issue is frequently seen in autumn when heating systems are turned back on after a long summer break, as pumps can often seize up during periods of inactivity.

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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