How much does it cost to fix Worcester Bosch error code E9?

Typical repair cost for the Worcester Bosch E9 fault is £120-£350 including labour.

E9 High

Worcester Bosch E9 Fault Code

Q: What does the Worcester Bosch E9 fault code mean?

Your boiler has sensed that it is getting dangerously hot and has shut itself down to prevent damage or overheating.

The Worcester Bosch E9 fault code means: your boiler has sensed that it is getting dangerously hot and has shut itself down to prevent damage or overheating.. It appears on 43 Worcester Bosch models in our database.

Technical description: Safety temperature limiter in CH flow or flue gas temperature limiter has operated

What causes the Worcester Bosch E9 fault?

This fault occurs when the internal sensors detect that the water or exhaust gases have reached a dangerously high temperature. The most common reason is a lack of water circulation, often caused by a failed internal pump or a blockage in the system pipework that prevents heat from being carried away from the burner. It can also happen if there is an air lock in the heat exchanger or if the sensors themselves have developed a fault.

This fault often appears during the first cold spell of autumn when the heating is turned back on after months of inactivity, as internal pumps are prone to seizing during the summer.

Typical repair cost £120-£350 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Worcester Bosch models that show the E9 fault code

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

Source

Worcester Bosch E9 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 27 April 2026