Vacuum breaker question

I recently replaced my outside hose spigot and vacuum breaker. The new vacuum breaker (Watts Series 8) performs differently than the old one that came with my house, and I was wondering if someone here could tell me whether or not this is a problem.

With the old unit, if I built up pressure in a garden hose (used a sprayer attachment and kept it closed), and then shut off the spigot, the vacuum breaker would release the pressure in the garden hose, spraying it through the relief holes.

With the new unit, if i build up pressure in a garden hose and then shut off the spigot, the vacuum breaker does not release the pressure and the hose remains pressurized. Thinking this may be a problem, I tried unscrewing the vacuum breaker on the side of the spigot. Water flowed backward through the vacuum breaker, out the unthreaded connection. Since water flowed backwards from the pressurized hose to the unscrewed spigot side and not out the relief holes, it seems to me that the vacuum breaker isn't doing its job.

Can someone tell me 1) when turning the water off, is the vacuum breaker supposed to immediately relieve pressure as with my old breaker, or if it's supposed to keep pressure as with the new one, and 2) was unscrewing the pressurized vacuum breaker a valid experiment to show that the vacuum breaker does not do its job?

Thanks for any help with this.

As I understand it, it's probably working right. The thing will prevent back flow caused by the inlet pressure being lower than the outlet pressure. When there is no flow, then you turn off the valve, the pressure is still the same at both sides, so there's no vacuum to break the seal and cause it to dump.

Thanks for the reply, jadnashua. So do you think it's alright that water from the hose side backflowed through the vacuum breaker? I thought it was supposed to prevent this, but perhaps the pressure differential wasn't great enough?

When you loosened it, could it have been the water from the breaker back to the faucet that came out?

jadnashua said:

When you loosened it, could it have been the water from the breaker back to the faucet that came out?

Click to expand...

No, way too much water came out.