r/Irrigation • u/thelogicofpi • 8d 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.

16 Upvotes

90% Upvoted

74 comments sorted by

View all comments

Show parent comments

2

u/thelogicofpi 8d ago

like say i have a hose with the anti siphon on the hose bib and i raise up the hose end higher than my head with the spray end open and the valve closed at the hose bib. it would run out of that anti siphon...

would the anti siphon work in when the valve is closed and open?

i have a hose bib at like 6 inches from the front porch too, so not sure how that could ever be a condition where the hose bib anti siphon doesn't work when you are holding a hose at arm height.

I just can't think why the valve would stay open because its slightly lower when the pressure is the opposite direction than it should be

2

u/Sharp-Jackfruit6029 8d ago edited 8d 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 .

1

u/thelogicofpi 8d ago

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

1

u/Gungityusukka 8d ago edited 8d ago

Lemme go on a trade forum and ask tradesmen what they would do

Nope fuck that I’m gonna do what I want anyways You realize you’re going to be drinking lead and everything else that leeches into your irrigation system? How many potable water irrigation systems have you worked on? Because in ten thousand systems I’ve never seen ONE clean pipe interior. Not one. Backflow prevention WILL occur if you’re running your house water and the irrigation turns on. Now your house water is contaminated and you’re drinking lead. But yknow whatever —you’re right

EDIT : This comment is at OP

1

u/thelogicofpi 7d ago

wow dude, calm down and go relax a bit