i23 Low

Worcester Bosch i23 Fault Code

Also written as I23 — same fault.

The Worcester Bosch i23 fault code means: your boiler is simply displaying its internal software version information rather than reporting a functional problem.. It appears on 1 Worcester Bosch model in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: HCM version number - For example “4”

DIY fix possible

Press the 'Reset' button on the boiler control panel onceWait for the display to return to the standard temperature readingIf it persists, turn the boiler off at the fused spur for 30 seconds and switch it back on

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Worcester Bosch models that show the i23 fault code

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

Source

Worcester Bosch i23 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