I understand the purpose of a vacuum breaker, and the need for it to "vent" the water in the hose when pressure is removed. The ones that I can find all do so by spraying the water out in all directions, which is annoying. Are there any that release the water more slowly, so it drips or gently flows onto the ground?
1it's not supposed to spray any water ... it's supposed to allow air to enter– jsotolaAug 26, 2022 at 6:00
Considering the backflow situation should be encountered very infrequently, what problem are you actually trying to solve here? I'm sure yours will spray less water around than a typical rain will– whatsisnameAug 26, 2022 at 6:08
1Are you trying to leave hoses pressurized 24x7?– Harper - Reinstate MonicaAug 26, 2022 at 11:10
This sounds like a defective vacuum breaker.
What a vacuum breaker "vents", working properly, is air into the hose when the hose pulls a vacuum. That's how it "breaks" the vacuum and prevents siphoning (should the house system become depressurized with an open valve and the hose connected.)
Typically that happens when water is shut off and the hose outlet is below the spigot.
So, if water is spraying out of the vacuum breaker, the one way valve is not functioning correctly as a one-way valve. The only way water is going to spray is under pressure. Spend a small amount of money replacing just the vacuum breaker (should not need to replace the whole spigot.)
If it is an older unit you can open it up and replace the seals, mine has 'O' rings.– GilAug 26, 2022 at 14:44
You can test this. If a rubber hose full of water is raised above the level of the breaker, water should drip or leak out the air valve up to a point ... but not to the point it "sprays". At some level of back pressure the air valve should close. I think that's 1 PSI over atmospheric. In theory that's 2 feet of water ... so you raise the hose up two feet and the valve should close. It won't actually work that way because the hose is coiled and it's not full of water and other real-world factors but the idea is ... you can test it.– jay613Aug 26, 2022 at 16:09
Possible answer assuming the following scenario is what you are experiencing:
Lets say you have a bib-mounted vacuum breaker and you have a hose attached to a reel with a spray nozzle on the end (or other shutoff on the end of the hose). If you leave the water on, and then roll up the hose, you create a situation where the pressure in the hose is greater than the house water pressure. The backflow preventer/vacuum breaker will spray out a burst of high-pressure water rather than allowing it to flow back into the house.
If that's the case, then turn off the hose bib, and relieve some pressure on the hose by using the spray nozzle or hose-end cut off valve and then reel up the hose. The now low-pressure back flow will just drip rather than spraying.
Many vacuum breakers are not rated to have the water turned on constantly and will fail prematurely if you do that.