Low
304 on Baxi 624 Combi

Your boiler is currently in a manual testing mode used by engineers to check its performance, which limits how the controls respond.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

What the manual says

Manufacturer manual

Chimney sweep mode is active (enabling setting of maximum and minimum output).

From this model's manual
Verified against the Baxi 624 Combi installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Press the Reset button for 1 to 3 seconds to exit the test modeTurn the selector dial or heating controls off and then back on againSwitch the power to the boiler off at the wall spur and then back on after 30 seconds

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