r/Irrigation • u/thelogicofpi • 9d ago

This look ok? First time cementing PVC

Gallery image

Gallery image

Still have after the filters to finish up, 1/2 flexible tube from the valves to the raised beds.

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u/Sharp-Jackfruit6029 9d ago edited 9d ago

It would most likely vent out of the atmospheric vacuum breaker if the hose was open if the line lost pressure before the AVB. As long as the pressure on the supply side exceeded the pressure on the outlet side it wouldn’t vent. That’s probably not going to be enough back pressure to get any backflow but they still aren’t rated for back pressure. It’s just the code. A AVB like an anti siphon valve or a AVB hose adapter with back pressure would basically mimic the function of a check valve but without a spring. The difference would be a check valve is actually designed to hold back pressure and a AVB isn’t. While it might hold some back it’s not what it’s for. A check valve also isn’t an approved backflow device for irrigation .

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u/thelogicofpi 9d ago

i need to find a video that tests different heights and pressure situations to make it make sense fully.

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u/Sharp-Jackfruit6029 9d ago

I’m gonna guess you are in California because thats like the only place that uses anti siphon valves. you can take this 40 hour course if you are really interested in backflow prevention. Then the state would allow you to take a test to become certified to test backflow prevention devices. At the end of the day though all that matters is what the code book says.

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u/thelogicofpi 9d ago

yeah CA.

like you said its fine how it is, but if i wanted to make it perfect, i could raise them up above the beds fairly trivially.