Vaillant P.008 Fault Code
Also written as P008 — same fault.
The Vaillant P.008 fault code means: your boiler is currently running its automated process to fill the system with water, which is a normal part of its maintenance routine.. It appears on 3 Vaillant models in our database.
Technical description: Fillingofproductwith water
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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.008: 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.008 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Vaillant P.008 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 7 July 2026