BoilerFaultCodesZanussi P1 Fault Code
The Zanussi P1 fault code means: your boiler is displaying a service setting notification rather than a breakdown, indicating the internal pump is being told to run at its maximum speed.. It appears on 3 Zanussi models in our database.
Technical description: To set the minimum CH pump speed to 100%
What causes the Zanussi P1 fault?
This code appears when the installer or a service engineer has manually activated a specific setting within the boiler's menu. It physically forces the internal pump to run at full power constantly for testing or to clear air from the radiators. It is not a hardware failure, but rather a configuration mode that has been left switched on.
DIY fix possible
Press the 'Mode' or 'Reset' button to exit the installer function menuSwitch the boiler off and back on at the main fused spur switchMonitor the display to see if the code clears and returns to the temperature display
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Zanussi models that show the P1 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Zanussi P1 fault code information on this page is sourced and cross-checked against the official Zanussi service / installation manuals for each affected model.
- Zanussi Ultra Combi manual (PDF)
- Zanussi Ultra Plus Combi manual (PDF)
- Zanussi Ultra System manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026