Low Information
1.A on Worcester Bosch Greenstar CDi Compact

Your boiler is temporarily running at its maximum power level, which is usually a normal setting used by engineers during testing or after a reset.

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.

Technical description

Max. output (heating)

What causes this fault?

This status occurs when the boiler has been manually put into its maximum power mode, often through the service buttons on the front panel. It typically happens after a reset or when an engineer is calibrating the gas valve to ensure the unit can handle peak demand. In most cases, it is not a breakdown but a configuration setting that needs to be toggled off to return to normal operation.

DIY fix possible

Check if the chimney sweep or service mode button has been pressedPress the Reset button to return the boiler to normal operationObserve the display to see if the code clears automatically after a few minutes

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