i20 High

Worcester Bosch i20 Fault Code

Also written as I20 — same fault.

The Worcester Bosch i20 fault code means: your boiler is displaying its internal software version, which indicates a computer communication error rather than a physical breakdown, but the unit will not operate while this message is present.. 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: Software version - CBS software version of main PCB.
Typical repair cost £150-300 (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 i20 fault code

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

Source

Worcester Bosch i20 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