P.02 Low

Vaillant P.02 Fault Code

Also written as P02 — same fault.

The Vaillant P.02 fault code means: your boiler is not in a fault state; it is simply running a pre-programmed test to check how it performs at its lowest power setting.. It appears on 23 Vaillant models 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: Minimum load test program

What causes the Vaillant P.02 fault?

This code appears because the boiler has been manually or automatically triggered to run at its lowest possible firing rate. It is an intentional test mode used to check the stability of the flame and the accuracy of the gas valve settings. Since it is a controlled test rather than a mechanical failure, your boiler will return to normal operation once the program finishes.

DIY fix possible

Wait approximately 15 minutes for the program to finish automaticallyPress the 'Back' button (represented by a left-facing arrow) to manually exit the testTurn the boiler off and back on again if the screen remains stuck

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Vaillant models that show the P.02 fault code

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

Source

Vaillant P.02 fault code information on this page is sourced and cross-checked against the official Vaillant service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026