How much does it cost to fix Worcester Bosch error code 285 / E9?

Typical repair cost for the Worcester Bosch 285 / E9 fault is £150-300 including labour.

285 / E9 High

Worcester Bosch 285 / E9 Fault Code

Q: What does the Worcester Bosch 285 / E9 fault code mean?

Your boiler has detected that the water returning to it is much too hot, so it has safely shut itself down to prevent damage.

Also written as 285E9 — same fault.

The Worcester Bosch 285 / E9 fault code means: your boiler has detected that the water returning to it is much too hot, so it has safely shut itself down to prevent damage.. It appears on 3 Worcester Bosch models in our database.

Technical description: Return temperature exceeded 95°C

Typical repair cost £150-300 (including labour)

Engineer required

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

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

Worcester Bosch models that show the 285 / E9 fault code

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

Source

Worcester Bosch 285 / 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