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New Member

Posts: 2

Location: Galt, California


Tuesday, January 2nd 2018, 6:24pm

antisiphon valve hiccup/surging...

So.. in 22 years I may have experienced this a time or 2 before.. system is a well system on 3/4" sched 40 pvc main(existing) set up on 3/4" Hunter antisiphon valves with 4" popups on swing joints with MP rotators 3000 series.. The system operates well just when shutting off it hiccups at one or two of the valves.. The valves are minimal one foot above the highest head. Lateral runs are long...any quick fix? inline check valve before the valves?? I flushed em several times.. suggestions?



Posts: 2,361

Location: USA


Wednesday, January 3rd 2018, 2:36am

Are you saying that water's coming out of the cap? Like back flow?
I'm asking because you want to put a check valve "before" the valve.
Are you suspecting that the main's losing pressure?
I'm not even sure why a small amount of drainage is a problem.
Are two valves doing it at the same time? Or one at a time?
Is there a master valve?
Maybe I'm making this too complicated. But a tad of back flow shouldn't be a problem. Maybe the sprinklers are forcing the water backwards when they go down because of checks in the heads.


Supreme Member

Posts: 5,323

Location: Metro NYC


Wednesday, January 3rd 2018, 1:07pm

Modern spring-loaded sprinkler heads can force water back at the antisyphon valves when a zone shuts off, even when the valves are more than a foot higher in elevation than the heads. This will result in some spillage at the valves, but it is not considered a failure of the valve or of the system design.

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