Medium
Not a fault code on Worcester Bosch Greenstar 15i System

Your boiler is currently in a manual testing mode used by engineers, which is why it has stopped operating normally.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

2 pulses | No light | Service mode selected to min, press service button to return to normal.

From this model's manual
Verified against the Worcester Bosch Greenstar I System 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

Locate the blue 'Service' button on the front control panel.Press and release the service button once.Observe the boiler to ensure it returns to standard operation and the pulsing light pattern stops.

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