High
ERROR on Worcester Bosch Greenstar i Junior

Your boiler's electronic brain is missing a crucial identification chip that tells it how to operate, so it has safely shut itself down until the part is properly installed.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

What the manual says

Manufacturer manual

IF THIS IS NOT DONE THE APPLIANCE WILL INDICATE ERROR AND WILL NOT FUNCTION. (Related to code plug not being re-fitted to the new control)

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

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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