BoilerFaultCodesVaillant 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 18 Vaillant models in our database.
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
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Avoid the next call-out bill
A cover plan would handle faults like P.02: no call-out fees, no surprise bills.
Affiliate links. We may earn a commission at no extra cost to you.
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.
- Vaillant ecoFIT Pure 412 manual (PDF)
- Vaillant ecoFIT Pure 835 manual (PDF)
- Vaillant ecoTEC exclusive manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026