On Tue, 4 Apr 2006 18:35:24 +0100, ashroyer
wrote:


Can I use a continuous pressure double check valve when connecting my
sprinkler system to my water line, such as this???

http://www.watts.com/pdf/ES-9DM3_M2.pdf

I've been recommended an Anti-siphon pressure vacuum breaker, such as:

http://www.watts.com/pdf/ES-800M4QT.pdf

But they are more expensive and much bigger.

There are no city codes in my area requiring the use of a backflow
prevention device though I'd still like to put something in.


Don't Anti-Siphon and Check Valves do different things?

If I understand it right, an anti-siphon valve allows
air INTO your hose/pipe when it demands more water than
you can supply, which keeps it from either (A) collapsing
your hose/pipe or (B) Sucking water backwards out of other
branches of your water system. Whereas a
check-valve/backflow arrestor keeps water from running
backwards in your hose/pipe when you get negative pressure.

It wouldn't hurt to have both.