i10 High

Worcester Bosch i10 Fault Code

Also written as I10 — same fault.

The Worcester Bosch i10 fault code means: your boiler is temporarily shutting down because it has detected that the internal water temperature has become dangerously high.. It appears on 1 Worcester Bosch model 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: Maximal temperature - This is the current temperature from the “maximal safety sensor” displayed in real time (rounded to 0.5°C units). The sensor is mounted on the top of the primary heat exchanger.
Typical repair cost £150-350 (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 i10 fault code

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

Source

Worcester Bosch i10 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