Hello - I will be building a deck off my house this summer and therefore need to reroute slightly the main copper line coming out of my house that runs into the ground and to the valves for my sprinkler system. Right after the copper leaves the house, it goes into a cylindrical thing and then back out again. The cylinder has two shut off valves. There is also a port where I can hook up my compressor each fall to blow out all the lines. My question is, does this cylinder with two shut off valves just provide one function; namely to allow me to isolate the pipes on each side of it when I blow them out, or does it serve some other function as well? If all it does it allow me to isolate the two sides, then I can build an easier contraption to do the same that will more readily connect to my compressor with a quick connect rather than having to screw in an attachment each year. If it serves some other purpose, then I guess I need to keep it when I reroute the copper pipes.

Thanks,
Rob

Hello - I will be building a deck off my house this summer and therefore need to reroute slightly the main copper line coming out of my house that runs into the ground and to the valves for my sprinkler system. Right after the copper leaves the house, it goes into a cylindrical thing and then back out again. The cylinder has two shut off valves. There is also a port where I can hook up my compressor each fall to blow out all the lines. My question is, does this cylinder with two shut off valves just provide one function; namely to allow me to isolate the pipes on each side of it when I blow them out, or does it serve some other function as well? If all it does it allow me to isolate the two sides, then I can build an easier contraption to do the same that will more readily connect to my compressor with a quick connect rather than having to screw in an attachment each year. If it serves some other purpose, then I guess I need to keep it when I reroute the copper pipes.

Thanks,
Rob
It's a pressure Vacuum Breaker, and yes, I do need it. Looks like I answered my own question :-)

Rob