BoilerFaultCodesVaillant L.022 Fault Code
Also written as L022 — same fault.
The Vaillant L.022 fault code means: your boiler has detected that there is not enough water flowing through your heating system, which usually means the pressure is too low or a valve is closed.. It appears on 3 Vaillant models in our database.
Technical description: Thecirculationwatervolumeintheheatingcircuitistoolow.
DIY fix possible
Check the pressure gauge on the front of the boiler; it should read between 1.0 and 1.5 bar.If the pressure is below 1.0 bar, locate the filling loop (a silver braided hose or internal tap) underneath the boiler.Slowly open the filling valve to let water in until the needle reaches 1.5 bar, then ensure the valve is tightly closed.
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Vaillant models that show the L.022 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Vaillant L.022 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