i15 Low

Worcester Bosch i15 Fault Code

Also written as I15 — same fault.

The Worcester Bosch i15 fault code means: your boiler is simply displaying the current outdoor temperature because a weather sensor is connected, which is a normal status reading rather than a fault.. 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: Out door temperature - This is the out door temperature displayed in real time (rounded to 0.5°C units). Only available if a Weather Compensation sensor has been fitted and Weather Compensation is active.

DIY fix possible

No action is required as this is a status notification, not an error.Check your boiler display manual if you wish to toggle the default display view back to the target room temperature.

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Worcester Bosch models that show the i15 fault code

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

Source

Worcester Bosch i15 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