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alohatim
June 11th, 2009, 05:30 PM
The plumber installed backflow preventers on all of our outside hosebibs. I recognize their importance, but I am wondering if mine are working right. Every time I turn off the faucet, I can expect to be doused as the pressure is released around the valve. Also, if I want to run the hose at a slow dribble, I can expect the same amount of water to be leaking from BFP.

Who designed these things? Are there better models that don't shower you when you turn them off. I can see that they really don't want you to take them off. It looks like there is glue in the threads and the lip that covers the threads is crimped down. Easier just to replace the whole hosebib.

I tried putting a plastic bag over the connection. It sort of catches the spray explosion and I only get partly drenched now. I have a 15' hose attached to tap. I am think of adding a valve at the end that hose and leaving the faucet on all the time. That way, when the hose bib gushes, I will be out of the way.

Does anyone have any better ways to deal with these contraptions?

68-eldo
June 11th, 2009, 06:53 PM
It sounds to me like the backflow preventer was not installed correctly.

Information can be found here (http://abpa.org/faq.htm).

This should be an anti siphon device.

I think the bfp should be mounted higher than what you can hold the end of the hose. Otherwise if there is a loss of water pressure the weight of the water will keep the anti siphon valve closed.

This is common on in ground sprinkler systems.

It would be interesting to know why it was installed on hose bibs.

alohatim
June 11th, 2009, 09:56 PM
I think they are installed correctly. We had the same type on our last house. They may be cheap or poorly designed. I think they are required on all the exterior hosebibs per the plumbing code (for new construction).

Ours aren't mounted very high--the faucets are about 2 feet off the ground. A little spring inside the BFP closes the valve in case of pressure loss and keeps hose water from reentering the house.

68-eldo
June 14th, 2009, 07:09 PM
That sounds like a check valve. But check valves donít vent out of the pipe like a suction break valve. A suction break valve should not allow water to escape. Iíve never heard of this for hose bibs. Guess Iím behind the times.

Nords
June 14th, 2009, 11:30 PM
Iíve never heard of this for hose bibs. Guess Iím behind the times.
Either that or we're not related to the manufacturers of backflow preventers.

I'm pretty sure that I spend more time troubleshooting & replacing them than anything else they reputedly do. I've never heard of anything contaminating the municipal water system from the discharge end of a garden hose.

68-eldo
June 15th, 2009, 06:14 PM
I'm pretty sure that I spend more time troubleshooting & replacing them than anything else they reputedly do. I've never heard of anything contaminating the municipal water system from the discharge end of a garden hose.

I think it is a rare event but I guess the BWS does not want to take any chances. Wouldnít it be smarter to put a check valve on each meter?

Maybe it is too logical to be practical.

alohatim
June 18th, 2009, 09:22 PM
Oh, yes. We are required to have a device next to the meter--a pipe comes up out of the ground a couple of feet, then a valve, then back down into the ground. That protects the utility water. They required that before they installed the meter.

The hose bib valves, I believe, are part of the plumbing code for public safety. I do sometimes use hose-end sprayers for fertilizer and pesticides. There is a real possibility that water can be sucked back into the house if there is no check valve.

cezanne
June 20th, 2009, 07:44 AM
Sounds like the vacuum breaker is doing its job. Releasing the pressure in the hose before shutting of at the hose bibb might help. You say that you might keep the faucet all the time...I'm not sure if those things (the type that is attached at the discharge) were designed to be under constant pressure though.
Did you ask your plumber what's up?

alohatim
July 13th, 2009, 07:33 AM
I spoke to another plumber who said there is no other real design for these things other than ones that you crimp on and ones the you use a set screw to keep on.

He confirmed that they are put on because of the plumbing code.

I am replacing the hose bib and will put a BFP on the end of a 15' piece of hose that I attach the main hose to.