Central backflow preventer for exterior faucets

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Old 08-10-15, 04:10 PM
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Central backflow preventer for exterior faucets

I recently had the backflow preventer on one of my faucets break because it was attached to a water timer. Apparently backflow preventers don't work well under constant pressure (i.e., the faucet was left on and the water timer was off most of the time, placing the backflow preventer under constant stress). We came home to find the faucet spraying water all over the place through the holes in the backflow preventer (this is what I have, Imgur).

As part of some work I'm doing on the exterior faucets, I'd like to replace the existing backflow preventers with something less prone to breaking under a similar situation. Is there a better type of backflow preventer or hose bib? Or, should I look into a central backflow preventer? If I use a central backflow preventer, it would be installed in the crawl space.
 
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Old 08-10-15, 07:04 PM
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What do you have now that broke? Was it one of the ones that screw on the end of the hose bib or was it part of the hose bib itself?
 
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Old 08-30-15, 10:59 AM
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Sorry for the delayed response. I didn't even realize that there was a reply to this thread. Yes, the thing that broke was one that you screw into the end the hose bib (Amazon.com: Arrowhead PK1390 Replacement Self Draining Vacuum Breaker: Home Improvement). I was able to get it off and replace it with a different brand (http://www.amazon.com/dp/B0046HA9S6/). However, I am concerned that it will break again since it would be under constant pressure (I would leave the hose bib turned on most of the time so that the connected timer can control when the garden is watered). I'm hoping to find a better alternative to this backflow preventer that is more reliable and robust.
 
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Old 08-30-15, 11:59 AM
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Apparently they make hose bibs with an internal vacuum breaker (https://www.plumbingsupply.com/hoseb...ml#sillfaucets, see "Sill Faucets with
Arrow-Breaker Internal Vacuum Breaker" section). I can't find much in the way of reviews on these, so it's hard to say whether they're prone to breaking. If they break, then it looks like the entire bib would have to be replaced.

I realize that you can get hose bibs with integrated anti-siphon devices that can be repaired without replacing the hose bib. However, I have only seen these in frost-free variants. However, I cannot install these on my house. The height of the hose bibs places them a few feet above the main floor, so they would poke into living spaces such as the mud room and living room.
 
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Old 08-30-15, 02:34 PM
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They certainly do make backflow preventers that can be centrally mounted although a crawlspace is not the best location. You would have to have all your outside faucets on one pipeline and then splice the BFP into that line. The cost may be an impediment, somewhere around $150-$200 depending on the pipe size. There is also the strong possibility that your LOCAL plumbing and/or health codes would require yearly testing of this BFP device by a certified inspector.
 
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Old 09-01-15, 09:05 PM
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Ok, it sounds like it's not worth the hassle to install a central backflow preventer. I'll just go with a hose bib that has an anti-siphon valve. Does anyone have experience with the Arrow-Breaker internal vacuum braker (https://www.plumbingsupply.com/hoseb...ml#sillfaucets, see "Sill Faucets with Arrow-Breaker Internal Vacuum Breaker" section)? It looks very interesting, but I'm not sure how robust it is.
 
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Old 09-02-15, 01:59 AM
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Your link doesn't work but ABP (Arrow Brass Products) faucets are fairly common in my area. I don't know of any faucet-mounted vacuum breaker that is rated for continuous upstream pressure with the use of a hose timer. You MIGHT be able to use a vacuum breaker made for an in-ground irrigation system. Watts 3/4 in. Bronze Pressure Vacuum Breaker-800M4-QT - The Home Depot
I'm pretty sure these are made for a constant inlet pressure and valved downstream usage but I can't guarantee that thought. Obviously you would need to securely fasten the assembly and then use some kind of hose from the house faucet to the inlet and then the timer on on the outlet. May need some garden hose to pipe thread adapters.
 
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Old 09-02-15, 10:26 AM
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Any reason you can't attach the water timer directly to the hose bibb, then attach the vacuum breaker to the outlet of the timer? That way, the vacuum breaker wouldn't be subjected to line pressure 24/7 and it would still protect the potable water system from backsiphonage.
 
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Old 09-03-15, 08:22 AM
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Well, gee. Here we are trying to come up with an expensive fix and Beachboy uses his brain to come up with a no-cost fix. Good idea!
 
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Old 09-03-15, 09:47 AM
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Agreed. Let's keep it simple. Thanks Beachboy for the great suggestion
 
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Old 09-03-15, 10:02 AM
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One thing you MUST remember is to remove the timer and disconnect the hose before the weather turns cold enough to freeze any water trapped. It is not enough to simply turn off the water on a "freeze proof" faucet as leaving the hose (or a timer) connected traps water in the faucet outlet and that WILL freeze and often break the faucet inside the wall.

If you do not have freeze proof faucets then you also need to turn off the water to the outside faucet (inside the house) and then leave the outside faucet turned on to allow any water to drain.
 
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Old 09-09-15, 02:27 PM
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Thanks for the reminder! I had not thought about freezing issues related to the timer/hose and will be sure to disconnect them in the winter. As for the hose bib and plumbing, all the plumbing is encapsulated in the thermal envelope of the house. The only part that is outside the thermal envelope is the couple of inches or so that runs through the exterior wall to the hose bib. The hose bib is located on a wall that's next to the heated first floor, so there's some (minor) thermal leakage through the wall that should minimize freezing.
 
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