How to reset a Worcester Bosch Greenstar boiler

Follow this guide to learn how to reset your Worcester Bosch Greenstar boiler

If your Worcester Bosch Greenstar boiler has suddenly stopped working or is displaying a flashing blue light, a simple reset might be all it needs to get back up and running. This guide walks you through the reset process for your Worcester Bosch Greenstar boiler, helping you restore heat and hot water quickly and safely.

Common Reasons Your Worcester Bosch Greenstar Boiler May Need a Reset

Understanding why your boiler needs resetting can help you avoid repeated faults. The most common causes include low water pressure, frozen condensate pipes during cold weather, blocked air vents, or issues with the thermostat. Power cuts and interrupted gas supply can also trigger a fault mode.

While a simple Worcester Bosch Greenstar boiler reset often solves the problem, persistent errors could indicate a more serious internal issue such as a faulty sensor, diverter valve, or heat exchanger. Always check for visible warning codes or flashing lights on the display panel, as these provide useful clues about the underlying fault. If your boiler frequently needs resetting, it’s a sign that it needs professional attention. Preventative maintenance and annual servicing can help catch small issues before they become costly repairs.

Don’t ignore repeated faults—contact a qualified engineer to ensure your home heating system is running safely and efficiently.

Worcester Greenstar CDi Classic Boiler Reset

To bleed your radiators you will need the following tools:

Press the reset button [2] for three seconds.

The reset button [2] and the fault indicator [3] will stop flashing.

If the reset was successful the boiler will return to normal operation.
If the reset was not successful then the alert code will be displayed again, and the blue operation/fault light will continue to flash.

Worcester Greenstar Si & CDi Compact Boiler Reset

To reset the boiler, press “Reset”.

“Reset” and a tick is briefly displayed.

Worcester Greenstar i Boiler Reset

To reset the appliance, press reset briefly once.

“Reset” and a tick is briefly displayed.

If the reset was successful the appliance will return to normal operation.
If the reset was not successful then the alert code will be displayed again, and the blue operation/fault light will continue to flash.

Worcester Greenstar i Junior Boiler Reset

In the event of a fault, the reset button will flash once per second and the blue mains indicator light will flash.

To reset the boiler press the reset button for approximately five seconds. When the boiler resets the reset button will no longer be illuminated.

The mains indicator will no longer be flashing.

Worcester Greenstar Ri Boiler Reset

In the event of a fault, the blue mains indicator light will flash if there is a fault.

To reset the boiler turn the Central heating temperature knob anticlockwise to the “RESET” position and hold for approximately five seconds and then turn the knob back to the original temperature setting.

When the boiler resets the mains indicator will no longer be flashing and the boiler will function normally, dependant on the programmer and room thermostat settings. A reset fault condition will exist If the electrical power to the boiler has been interrupted. Reset the boiler as described above.

Is your boiler still not working?

Sometimes, unfortunately, resetting your boiler is not enough to get it back up and running again. If your boiler keeps going back into fault mode you will now need to call a Gas Safe registered engineer.

PDF Gas & Heating have Gas Safe engineers on hand to come to your rescue, we can diagnose and repair your boiler quickly and efficiently. Get in touch