Low
5 pulses on Worcester Bosch Greenstar

Your boiler has been left in its internal testing mode, which is usually only used by engineers during a service or setup.

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

Service mode switch in max position

Shared across the Greenstar range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s 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 horizontal dial on the front of the boiler control panel.Check if the dial is turned all the way to the right (maximum position).Turn the dial back to your desired temperature setting to exit service mode.

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All 6 fault codes on the Greenstar

Seeing a different code? Every code this model can display, in one place.

2 pulsesFast flashN/ASlow flash (normally off, flashes on)Slow flash (normally on, flashes off)

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