Leaky back flow preventer

[Ellenk]

The back-flow preventer on my outside tap was leaking where the preventer screws onto the tap. When I tried to loosen the locking screw to tighten or remove the preventer, the screw snapped off. Yep. The back flow preventer doesn't bother me per se, but I would like to use timer value on the tap for irrigation. Right now, if I add a timer valve and open the tap, I get a steady drip from the tap. Is there any way of sealing the tap-preventer junction?

 

[hj]

No, and the screw is designed to break off, usually when it is installed. Change the valve AND the backflow preventer, since it will NOT "unscrew".

 

[Sponsor]

 

[FullySprinklered]

The break-away set screw on the vacuum breaker was put there to reinforce the self esteem of people who make bad decisions. I was put here to show you how to circumvent the BS.
Take a 3/16 drill bit and drill a hole on either side of the BS break-away set screw. Take a flat blade screwdriver and work it up under the edge of the device and pry it up a bit. Then unscrew the MF and throw it in the shrubbery. Now screw your timer thingy on and do your thing.

 

[hj]

There are easier ways to remove the BFP, but, after you go to the work of doing that, then you will probably replace the hose faucet because it is also worn out.

 

[Flapper]

You maybe can just unscrew it with more force because I think usually (but maybe not always) the set screw has a flat bottom that just presses on so when you unscrew it with force, it will rub the tips of the threads off a little bit but not much and it'll still look good and work perfectly fine, whereas if you try to drill it out you might drill into the threads and make an ugly damage or crater or something.

To drill it I find the best thing to do is use a larger drill bit, and drill at the set screw (the bit will drill the screw and surrounding brass) until either the screw pops out or you just start seeing the threads, then try unscrewing it.

You can also slice away at it and stuff... basically you are probably going to need to do some hacking.

You said the screw snapped off, so the screw wasn't already snapped off? It's probably not very tight and you maybe can just unscrew it with some force.

 

[hj]

1. The set screw will scrape the threads off the faucet and mutilate them so a hose will not screw on properly
2. The screw is hardened so it will NOT "drill out" easily

 

[Flapper]

1. The set screw will scrape the threads off the faucet and mutilate them so a hose will not screw on properly

If the screw has a flat bottom, it probably doesn't go in deep, so it will only scrape off a little of the tips of the threads.

2. The screw is hardened so it will NOT "drill out" easily

That's why I suggest using a larger drill bit; if you use a bit the size of the screw, it will just push to the side and drill between it and the brass;

 

[hj]

Most bits will not even drill the set screw/

 

[FullySprinklered]

We're not on the same page. The broken off screw will not drill out, but if you drill the brass on either side, the nub of the government-mandated screw will fall out into the mulch. THEN, unscrew the vacuum breaker. If the threads aren't perfect when you get through, be informed that it ain't the threads that seal the spigot to your device or hose. It's the washer on the female side that seals it. Quote: drill a hole on either side.

 

[Flapper]

Most bits will not even drill the set screw/

I used cheap drill bits, and it worked fine, just took some oil and force.

 

[Flapper]

The broken off screw will not drill out, but if you drill the brass on either side, the nub of the government-mandated screw will fall out into the mulch.

Yeah, same as using a larger bit and drilling the entire screw and surrounding material

 

[FullySprinklered]

Ok, I'm eating crow here. I removed two of those little darlings today and it wasn't as easy as I described it. Throw in 98 degree temperature and 100% humidity and a few dozen mosquitos, and it was a hades safari. The shrubbery was sticky, too.
It took a couple of holes on either side of the break-away screw, plus a few more high-angle holes to make channels on either side of the screw. THEN, stick a flat screwdriver into the canyon of mutilation and pry it up until the set screw falls out. Then remove the device. I'll try a more colorful description next time.

 

[Smooky]

Here is a video where a guy cuts the screw out with a dremel tool:
https://www.youtube.com/watch?v=09yc1VSVZck
There was another video where a guy used a dremel tool to cut a slot in the screw and then unscrewed it with a screw driver.

 

[FullySprinklered]

I checked it out, Smooky. Always eager to see what other folks come up with. The drill took about the same amount of time, but I can see that a cordless dremel could be helpful in that and many other situations. Not sure, but there might be a greater likelihood of thread damage with the Dremel in the wrong hands. Like mine, perhaps.
North Carolina, huh? You got a rack of PVC pipes on your front bumper?