Leak test a water hydrant/facuet ?

[CobyRupert]

Assuming my water hydrant for the horse barn ever thaws out, I suspect that part of the issue may be if the seal has a slight leak, with probably not the best drainage around the weep hole.

Other than pulling the hydrant and inspecting the gasket, even after I reassemble how can I be 100% sure there's not some leak through?

I'm thinking of installing a pressure gauge in the house basement that feeds the underground line, downstream of the basement shut-off valve. Will this work to do a leak test?

If I shut off the feeder valve in my basement and watch the pressure, if the hydrant valve is not leaking, how long will it hold the pressure? Or conversely, if there's a slow leak at the downstream faucet, how quickly will the pressure drop?

 

[Loadstar]

Yes you can install a pressure gage. You can also listen to it when turning it on. If you crack the valve slow you can listen to hear water rushing past the valve if the hydrant has been off a couple days. If you Get a Gage get a gage close in scale to your pressure. Say if it's 90psi get a scale 0-100, this allows to more closely see pressure changes. If its a frost proof hydrant that stands up out of the ground you can typically rebuild them without digging them up. I am actually in the process of doing this to mine. If you need better drainage around the weep hole, there is no way around that. You have to dig it up and fix that.

 

[CobyRupert]

I'm curious that if I do a pressure test, can I expect a good, non-leaking faucet to hold the pressure for an hour, hours, days?

 

[DT86]

If it is a frost free and has a slight leak, I have had good luck with re-adjusting the travel of the rod. On mine it's a square head bolt. Shut it off, loosen the bolt, open the handle a bit, tighten the bolt and close again. You can usually hear the water flowing by putting your ear up to the hydrant.

(The only time re-adjusting did not work for me was on a hydrant at the bottom of a big elevation change, it simply picked up too much pressure for the hydrant to overcome. I ended up having to cap it off and move the hydrant else where.)

You can unscrew the top from the upright pipe and replace the rubber part if still doesn't work.

If you do need to dig it up due to poor drainage I have a few tricks for that too. Just let me know.

 

[Loadstar]

Now come on if a good non-leaking faucet does not leak it will hold until it's bad and it leaks
but in all seriousness if it was mine and it was suspect I would start with the following.
-shut the hydrant line main down
-don't use for 24 -48 hours or more if possible
-SLOWLY reopen hydrant main and listen for an inrush of water.
-then let's talk gages
A good hydrant should not be bleeding down. I have two on a water line. One is an OLD meril maybe and I know it leaks out the weep when on, the other drips out the faucet when there is line pressure but the hydrant is off. The first i mentioned will not freeze because it's leak is down deep. The second freezes up because it leaks by up the hydrant line and probably doesn't have good weep drainage either.

 

[CobyRupert]

Why would there be an inrush of water to hear?
With the main in the basement turned off, would any water drip past a leaky seal? For that to happen, wouldn't there have to be a way for air to get in?

 

[Loadstar]

Why would there be an inrush of water to hear?
With the main in the basement turned off, would any water drip past a leaky seal? For that to happen, wouldn't there have to be a way for air to get in?

Say your line is 100 psi and you shut it off. If the pressure drops from the shut off to the hydrant to 50 psi, when you slowly crack that valve you will hear that water equalizing.

I'm working out of town this week but staying in our vacation home. We leave the water off when gone. Upon arrival I went in and flushed a toilet. That drops the pressure off the line, so when I turned it on at the meter I could hear that water moving to equalize pressure. I stand there for a bit to make sure it stops incase there is a broken pipe. Once I hear it stop, I know i have no sizable leaks.

Try it on your hydrant.
-Shut it off
-walk out and open hydrant briefly to bleed pressure
-walk back in and slowly open water line back up

 

[CobyRupert]

Water is incompressible. Aren't you hearing the water refill your toilet tank?

 

[Loadstar]

Yes, your right, but what I'm saying is if you shut the main off and bleed pressure off the hydrant, you will hear the line repressurize when you barely crack the valve. I am just giving you a SIMPLE, quick, and nearly effortless way to first check it out.

 

[Billrog]

If the hydrant is leaking with it shut off especially with pour drainage won't water be dripping from the top when it's off. That's how I discovered one of mine was leaking and had to adjust the rod.

 

[JRobyn]

The problem would be that the hydrant valve is slightly leaking and the weep/drainage is OK, allowing the leaked water to drain off without filling the riser pipe (except for maybe just a little).

I think shutting off the upstream supply and then monitoring the pressure in the line is your best test method. At least as long as you are pretty sure that the shutoff valve doesn't leak just slightly. Unfortunately in my experience, most valves, with the possible exception of teflon-seat ball valves DO leak just slightly. If the pressure stays solid within 5-10psi over a time period of an hour or two, that would indicate to me that everything is as tight as could be expected.

- Jay

 

[CobyRupert]

If the hydrant is leaking with it shut off especially with pour drainage won't water be dripping from the top when it's off. That's how I discovered one of mine was leaking and had to adjust the rod.

Yes, in the summer it would drip from the top if the leak rate is greater than the soil absorption rate out the weep hole (and given a long enough time for the difference to fill the 7' tall pipe and come out the top. That could take a while.). In the winter, however, the water would slowly fill the stanchion pipe until it freezes solid (no drip).
-OR the seal could be fine, but the soil is saturated and the stand pipe doesn't drain when you shut the valve off and the water left in the pipe freezes. Hard to diagnose from above ground.

The problem I'm trying to eliminate is "Does the seal leak?".

The problem would be that the hydrant valve is slightly leaking and the weep/drainage is OK, allowing the leaked water to drain off without filling the riser pipe (except for maybe just a little).

I think shutting off the upstream supply and then monitoring the pressure in the line is your best test method. At least as long as you are pretty sure that the shutoff valve doesn't leak just slightly. Unfortunately in my experience, most valves, with the possible exception of teflon-seat ball valves DO leak just slightly. If the pressure stays solid within 5-10psi over a time period of an hour or two, that would indicate to me that everything is as tight as could be expected.

- Jay

Thanks, that's the kind of info I was looking for.

I realize I might have any (or all of) the following problems:
1- Leaky valve seal
2- Bad/saturated weep hole drainage (which could be caused by #1)
3- Too shallow of a feed line (upstream of the valve) / Really, really deep frost this year.

-I'm trying to diagnose/eliminate #1 at this point (well, when it thaws)
I'm going to install a pressure gauge at the supply end in my house basement to check the valve. I'm also going to install a cleanout (tee) at the supply end so that I can run 1/4 tubing through the line with a hot water supply hooked to it, the idea is to feed the hot water tubing down the 1-1/2" water line with a stiff wire-snake.

 

[ovrszd]

Water is stable. Just like Hydraulic Fluid. It cannot be compressed measurably under normal conditions. So. Install your gauge, pressurize the line, seal it off. If you have the slightest leak you will, within a very short time, see your pressure drop to zero. Only expansion that can be overcome is the stretch in the plumbing. That is why I said "within a very short time". A slow leak will allow the plumbing to decompress before the pressure drops considerably.

I think you already realize you have a leak in your hydrant shutoff mechanism. As others mentioned you can probably adjust it and stop that. If not, as others mentioned, you can pull the mechanism out of the hydrant without digging it up and replace the rubber seal at the bottom of the hydrant rod. And as others mentioned, your seep hole issue is secondary and digging is required to fix that problem, even if it's something so simple as the weep hole crusting shut over time.

 

[CobyRupert]

Thanks ovrszd. I was looking for confirmation.
I think the pressure switch will be a good tool to prevent problems going into next winter, and to save my well pump from cycling on/off over the summer if a seal goes bad.
Winter is NOT the time to find this out.
The problem is my wife/and daughter operate the valve 99.9% of the time, so things that "should' be detectable : I.e. the plunger rod has slipped on the handle, or you don't hear the water immediately draining (detect a vacuum) upon shut-off, or the effort to operate the handle changes, etc.. it won't get detected until it something goes really wrong.