An automatic air vent can be affected by water quality issues, such as excessive debris and particulates from corrosion, hard water scale or just plain dirt. The result can be poor air release or water dripping out of the vent cap and onto the floor. Most of the time, all that is needed is a good cleaning. If that doesn't do it, a replacement cover and float is a simple and inexpensive rebuild option.
Caleffi has a full family of DISCAL Air Separators, DISCALDIRT Air and Dirt Separators and our newest DISCAL DIRTMAG Air and Dirt Separators with magnetic dirt removal. All the air vents on these separators can easily be cleaned and repair parts are available if needed.
Check out this short video; Cody Mack will explain how it's done!