SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

Hello,

I just purchased a new house with a irrigation system. I climbed under the house into the crawlspace and found a Wilkins 975XL back flow preventer. There appears to be a main shutoff valve, an input and output valve for the back flow preventer and then 4 test cocks. There is no t junction after the back flow preventer to connect an air source.
So here are my questions.

1. Is it ok to connect an air source to the #4 test cock to apply pressure to the lines and blow out the heads. If so can you by an adapter to connect to an air compressor or do you have to make up something.

2. What is the best way to drain or empty the back flow preventer. I'm thinking that it might not be necessary since it's in the crawl space and the main water line to the house is not insulated nor are any of the other water lines. I'm in Richmond Virginia.

Thanks,
Jason