High
2967 on Worcester Bosch Greenstar 4000

Your boiler has detected that water isn't flowing through its internal heating system as freely as it should, so it has shut down to prevent parts from overheating.

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

The temperature difference between supply temperature sensor and temperature sensor at heat exchanger is too large

From this model's manual
Verified against the Worcester Bosch Greenstar 4000 installation & service manual, page 77.
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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