Low Information
P3 on Worcester Bosch Greenstar 25HE

Your boiler is simply showing that it is going through its normal starting process and trying to fire up.

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

Boiler indicates start-up sequence

What causes this fault?

This occurs when the boiler's internal control board begins the ignition sequence to provide heating or hot water. It isn't a failure, but rather a status update showing that the fan is spinning and the electrodes are preparing to spark. You will typically see this for a few seconds every time the boiler starts a new cycle.

DIY fix possible

Wait for the boiler to complete its start-up sequenceCheck that your thermostat is calling for heatEnsure the gas supply is turned on if the code persists

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