Leaking anti-siphon faucet (<--help please)
A few of my neighbors have an anti syphon, frost free hydrant to which they attach their garden hoses in the summer. Note: an anti syphon faucet is not a requirement in our area.
A couple of these have 'popped' and had to be attended to because the water was gushing out. We have since learned that these devices often fail and become a nuisance. They fall into the category of being a 'plumber's friend' if your are unable to solve the problem yourself.
So, here is an easy permanent solution if you want to disable the anti syphon feature. Note: there are a number of models so this description would apply to a Mansfield-type faucet. Others are similar to a Mansfield.
Our neighbors have faucets with the anti syphon feature topped with a dark gray-black plastic cap. The cap is not threaded and just rotates if you try to twist it. So, just put your index fingers on either side of the cap and lift it off.
Under the cap you will find a round fitting; usually plastic (and white in the case of my neighbors). Use a gripping device such as an adjustable wrench or slip joint pliers. Rotate the fitting in an anti-clockwise direction. In the model my friends have, you will find that when you get the fitting out, there will be three pieces to it. Note: save that round fitting that you just removed from the hydrant; the other two pieces aren't important.
Now here is how to disable the anti syphon feature. When you get the fitting out of the faucet, you will see a small hole at the bottom where the fitting came out; it is about one quarter of an inch or so. Through that hole, you can see the spindle that is attached to the tap handle which turns the tap on and off.
The object of this exercise is to block that hole to prevent water escaping up and out through the top of the hydrant. In the model that we have in our area, a dime (ie. a ten cent piece) can be dropped over that hole to block it off. Then get a rubber washer and drop it on top of the dime. A rubber washer that fits on a garden hose might by the correct size. Note that the rubber washer was NOT put in first on the chance that the washer might somehow become twisted and then work its way into the faucet and thus block the water flow. So, dime first and rubber washer on top. Then put some teflon tape on the threads of the round fitting that you first removed. The teflon tape, commonly available in the plumbing department of Lowe's, the Depot or Ace, will assist in making a tight seal to prevent water leakage.
Then take that fitting and screw it into the hydrant clockwise. Note that this is plastic and you can screw the fitting in so it is snug but don't overtighten because it will crack. Put the plastic cap back over the fitting.
One of my friends who did this has left the plastic fitting in for three summers without a problem. Another friend searched around and found a brass fitting to take the place of the plastic one which he used only temporarily.
Another consideration is the handle of the hydrant. One of my friends didn't like the feel of the device when he turned the water on and off with the handle. He was concerned that the spindle inside the hydrant would break off. So, he attached a screw on faucet with a ball valve to the hydrant. He keeps the hydrant open all the time. He uses the handle on the ball valve to control turning the garden hose on and off. At the end of the summer. he shuts the water off inside the house. He then leaves the ball valve tap open to drain the water in the hydrant before the freezing weather comes.
So far, these modifications have worked fine for several summers.
So, that's the DIME solution for a wall hydrant if you care to use it.