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 28 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 →Vaillant models that show the P.02 fault code
Click a model for the full fault code list and model-specific repair notes.
- Atmomax
- Combi Compact 242EB
- Combi Compact 282EB
- ecoFIT pure
- ecoFIT Pure 418
- ecoFIT Pure 425
- ecoFIT Pure 435
- ecoFIT Pure 825
- ecoFIT Pure 830
- ecoFIT Pure 835
- ecoTEC exclusive
- ecoTEC plus
- ecoTEC Plus 615
- ecoTEC Plus 620
- ecoTEC Plus 625
- ecoTEC Plus 630
- ecoTEC Plus 635
- ecoTEC Plus 65
- ecoTEC Plus 826
- ecoTEC Plus 832
- ecoTEC Plus 836
- ecoTEC Plus 840
- ecoTEC Plus 938
- ecoTEC Pro
- ecoTEC Pro 24
- ecoTEC Pro 28
- ecoTEC Pro 30
- ecoTEC sustain
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 27 April 2026