Low Service
5 pulses on Worcester Bosch Greenstar 12i System

Your boiler has been manually put into a high-power service mode by a person, and it simply needs to be switched back to normal operation.

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

No light Service mode selected to max, press service button to return to normal.

What causes this fault?

This status occurs because the 'Service' button was physically pressed to put the boiler into its maximum power testing mode. It is almost always caused by an engineer or homeowner accidentally leaving the manual override active during maintenance or inspection. The boiler is not broken; it is simply waiting for a command to return to its standard daily settings.

DIY fix possible

Locate the button with a 'spanner' or 'service' icon on the boiler control panel.Press the service button once briefly.Observe the display to ensure the blue light stops pulsing and returns to a steady state.

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