WTF is a Check Valve for on an OBA setup?

[PierCed_3]

I have been looking for one of these for my OBA setup and I am wondering thier functionality. I cannot find any description for this anywhere. I can only find dimensions and such. Do I need one of these at all for my OBA setup?

 

[old school]

The check valve is also called an unloader. What this does is keep the presure in your tank but it lets the presure off of the compressor. This is a lot better on the valves upon start up. I run one one my OBA and if nothing else it seems to keep air in my tanks longer. I can shust things down and still have air in my tanks in the morning. Nothing can leak past the compressor valves.
WW Graingers in SLC has them>

 

[bobdog]

You need one. The valves in the compressor will not hold air in the tanks very well. Not all check valves have an unloader function And you really don't need one but If you want one they have them. Many pressure switches can provide an unloading function also.

 

[crimsonride]

It lets air go one way but not the other.

 

[PierCed_3]

Thanks! That sums it up for me. I have been killing myself trying to figure out what that is.