BoilerFaultCodesVaillant F.022 Fault Code
Also written as F022 — same fault.
The Vaillant F.022 fault code means: your boiler has stopped working because the water pressure inside your heating system has dropped too low to operate safely.. It appears on 3 Vaillant models in our database.
Technical description: Operating limit filling pressure reached (pressure too low)
DIY fix possible
Locate the external filling loop (a silver flexi-hose) connected to the pipework underneath your boiler.Slowly open the valve(s) on the loop to allow water into the system until the pressure gauge reads between 1.0 and 1.5 bar.Close the valve(s) tightly and check the boiler display to see if the fault code has cleared.
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Vaillant models that show the F.022 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Vaillant F.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