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Starting Member


Tuesday, August 16th 2005, 1:31pm

Backflow issue??

I have a rainbird ASV Brass Manual Anti-Siphon Valve that leads into a control valve (not sure what brand). I have a constant light leak along that whole line even with the system off. I turned off the manual valve but there is still water in the control valve. If I turn the contol valve on manually some water comes out but not enough to turn the sprinkler system. I'm not sure what to check from here. I did buy a rebuld kit for the anti-siphon valve but that did not change anything. Any troubleshooting suggestions from here. I was thinking about shutting the water at the street and opening up the control valve to check for damage. Any help is appreciated, the desert is killing my plants quickly.


Supreme Member

Posts: 5,292

Location: Metro NYC


Tuesday, August 16th 2005, 2:37pm

Basically, what you got is a piece of plumbing fraud. Nowhere in the United States is such a device usable as backflow prevention if there are any other valves downstream of it. All it is good for, is manual on-off flow, with atmospheric vacuum breaker protection, if it is at least half a foot higher than any heads or pipe it feeds.

Don't feel too singled out, you have company. Lots of systems were incorrectly plumbed, and done so to avoid the expense of correct plumbing. The correct device for backflow prevention, when it can be higher than the plumbing it feeds, is the Pressure Vacuum Breaker.

This still doesn't fix a leaking valve, and the quickest remedy is to buy a new valve and replace the bad one with it.

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