
Vaillant Boiler Problems and Fault Codes
Vaillant boilers are reliable but can develop faults, either as a symptom like no hot water, cold radiators or dropping pressure, or as an F-code on the display. This page covers both: the most common Vaillant boiler problems and what causes them, then every Vaillant fault code we cover with a link to its full fix guide. Some clear with a reset or a pressure top-up; others need a Gas Safe engineer.

