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

The Master Valve in the basement is not a good idea, that is just asking for trouble. Is there a particular reason you are placing the master valve in the basement? A plastic valve is just fine. Flow control is always a good option, and a jar-top valve makes service a little bit easier.

I would go with the Hunter HPV. The HPV has rigid internal support to prevent stress failure in high pressure situations. It also has a porting system with a superior ability to filter dirty water that also closes slowly to suppress water hammer. The HPV also has a flow control option that assures efficient operation when accurate flow management is required. If you are leaning more towards a brass valve, then I would go with the HBV, same type valve, only brass instead of plastic, and of course, a lot more expensive.

Unless you are in a state where a double check valve assembly meets the plumbing standards for sprinkler system backflow protection, you can abandon the indoor master valve idea. An indoor master valve almost certainly means an indoor backflow preventer, since the backflow comes first. And if a double check valve assembly isn't approved, that leaves only the costly and drippy 'reduced pressure principle backflow prevention assembly'

You'd be better off with two outdoor master valves, and a controller that can handle the electrical load, like a Hunter ICC

What city? I would bet hard money that you can't find that in writing. I pull out atmospheric vacuum breakers all the time, because nowhere on the planet Earth are they approved for backflow protection with any valves downstream of them. You can ask the manufacturers, and they will tell you the same.

Understand this about the plumbing codes - your city does not make the rules. Your state has a building code, and the building code will refer to one or another regional plumbing codes. California wrote their own rules, and refers to just about nobody. The only thing your town or city can do is set tougher rules than the regional codes. One such is when a town will absolutely forbid the use of atmospheric vacuum breakers.

Spend some time at your local library, and ask your reference desk for the code book. There are about three or four valid forms of lawn sprinkler system backflow prevention, and you will see them spelled out in the code. A dual check valve has no place in a sprinkler system, because it cannot pass the very simple requirement of <b>"Prove to me that it works."</b> - that's where the codes set the bar. If you still are uncertain about this, go and ask the town official that told you that a dual check and a vacuum breaker was good enough to put it in writing on official letterhead, and to sign and date it.

If you are going to do a proper job, you are going to have to change your design or upgrade your components.

That is true. My state and city codes (available on the web) both approve of the use of DOUBLE check valves in certain cases, but never a DUAL check valve. There is a difference, double checks are testable and have a series of pressure test hookups. Look into using a Double check in your application. That is what I have on my acreage private well because a PVB would have had to been located about 12 feet up the side of my house. Make sure you study this, a Dual check will not pass. best of luck.

Many regional codes have been changed to eliminate the double check valve assembly as a lawn sprinkler system backflow protection option. If this home is in one of the states that won't allow their use (and it's a flat property) then it would make economical sense to leave the indoor plumbing alone, and to install a pressure vacuum breaker (PVB) at each point where the pipe exits the house. This doesn't get you any master valve(s) but if you get good zone valves with flow controls on them, you can run with plenty of reliability.

plastic or metal? well i can say all plastic sprinkler valves will hold pressure just as reliably as a metal one, but they dont hold up as long as a metal valve. Plastic has a tendancy to shrink and expand more than a metal valve leading to leaks in the long run. However if you are using pvc pipe id reccomend a valve with a plastic body because its so easy to install, forget threaded connections with plastic valves, you can expect leaks over time. If you want to do it cheap and you are gonna run 3/4" PVC you might as well get a plastic valve with a solvent weld slip connection. Solvent welded connections are much more reliable than threaded connections due to shrinkage and expansion due to pressure differences in temperatures. Since it is going to be in your basement and you dont want water to drip from the fittings or pipe id reccomend PVC pipe since its cheap and it wont sweat condensation all over the place like copper or galvanized. also dont forget pvc pipe is rated for over 200 psi of water pressure if its cemented right.