2970 B High

Worcester Bosch 2970 B Fault Code

Also written as 2970B — same fault.

The Worcester Bosch 2970 B fault code means: your boiler has detected that the water pressure in your radiators is falling much faster than expected, which could indicate a significant leak.. It appears on 4 Worcester Bosch models in our database.

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.

Technical description: Pressure drop in heating system too rapid

What causes the Worcester Bosch 2970 B fault?

This fault occurs when the boiler detects a sudden and significant loss of water pressure within the central heating circuit. It is usually caused by a large leak in the pipework or a failure in internal components like the expansion vessel, which forces water out of the system. The boiler shuts down as a safety precaution to prevent the internal heat exchanger from overheating without enough water to cool it.

This fault is more common when the heating is first turned on after summer, as the change in temperature and pressure can stress weakened seals or joints, leading to new leaks.

Typical repair cost £100-350 (including labour)

DIY fix possible

Check all visible radiator valves and pipework for signs of water leakingTop up the system pressure to between 1 and 1.5 bar using the internal filling linkRestart the boiler to see if the code clears and the pressure remains stable

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Worcester Bosch models that show the 2970 B fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Worcester Bosch 2970 B fault code information on this page is sourced and cross-checked against the official Worcester Bosch service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026