BoilerFaultCodesZanussi uP Fault Code
Also written as UP — same fault.
The Zanussi uP fault code means: your boiler is currently stuck in its startup or programming sequence and is not yet ready to provide heat or hot water.. It appears on 3 Zanussi models in our database.
Technical description: PCB Power up / Programming Mode
What causes the Zanussi uP fault?
This fault occurs when the boiler's main internal computer loses its configuration or gets stuck during its initial boot sequence. The most common reason is a power surge or a failing printed circuit board that can no longer hold its basic programming instructions.
DIY fix possible
Wait up to 15 minutes for the programming cycle to finish automaticallyTurn the boiler power off at the fused spur switch, wait 30 seconds, and turn it back onPress and hold the 'Reset' button for 3 seconds
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Zanussi models that show the uP fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Zanussi uP 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 31 August 2026