![](https://irrigationdirect.com.au/wp-content/uploads/2016/09/comb-air-valve-img.jpg)
When to use:
Throughout your irrigation system to allow small amounts of air to expel while under pressure. The key difference between these and vacuum breakers is that they work when the system is on and discharge only small amounts of air
How they operate:
A rolling seal mechanism allows small amounts of air to expel.
Once a specified amount of air builds up, the air pushes down the rolling seal, allowing it to escape