High
252 on Worcester Bosch Greenstar 27CDi

Your boiler's internal computer is experiencing a temporary processing error that is preventing it from starting up correctly.

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

Stack overflow

From this model's manual
Verified against the Worcester Bosch Greenstar 27cdi installation & service manual, page 81.
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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