Originally Posted by DanaMac
The best way is to blow out from a connection down stream of any backflow preventer. But we blew out through the PVB or RP on probably 700 of the 900 we did last year. Do it right, and you won't have a problem. it's not my preferred method, but I won't be able to convince the other 700 to change their set up when it's been done this way for years. And no way I would have time to change them all during the blow out season.
if we are doing freeze damage repairs in the spring for a customer, we add a tee in there for blowing out.
Same as here, its a waste of time explaining this to anybody we always would get "that's the way its been for 10 years" so we just dropped the matter a together.
It's rather comical, we have some cities that will not pass a backflow unless there is a 3/4" threaded drain cap that is used to drain/winterize from and others that will not pass a backflow if there is any threaded connection before the backflow.