Frostproof Hydrant repair

[k miller]

Well I learned that you cannot leave a hose attached to a frostproof yard hydrant in freezing temps. Got away with it for 24 years until now. Standpipe split along it's vertical seam. Got it dug up and new hydrant installed but then I see a hole in the original standpipe from corrosion AND a crack in the 90* elbow connection from the water line. So that brings up a few questions as I have zero plumbing expertise other than kitchen faucets, sink traps, and ripping out flow restrictors in shower heads:

Do I only need to replace only the 90* elbow?

Teflon tape enough for galvanized-to-brass fittings?

There's a backflow checkvalve already in place but it's 24 years old - any reason to replace it while it's exposed?

How did the 90* elbow crack? Freeze? It's at 24" below grade as per my local frostline data (Lexington, KY).

The drain-off leaching area is basically dense-grade type fill without any filter fabric and not very deep (I'm going to use river rock shrouded in landscape fabric and dig out a deeper pocket below weep-hole) so is it possible that the standpipe corrosion is from poor choice of fill and fill depth at original install resulting in continuously saturated soil? Or is it typical for this to happen to galvanized steel in alkaline soil? I sealed the new hydrant standpipe in Flexseal tape. I've also got another non-functioning frostproof hydrant that the same contractor installed just inside my pole barn, but he put it so close to a main cross-member that i cannot remove the head. That gives you some idea why I doubt either were installed with due diligence. Gotta dig that one up next.

The weep hole in the side of base of the hydrant that lets out the volume of water in the standpipe when handle is put in the shut-off position showed no signs of blockage.

I did at least learn to just lay there and watch the fittings for a while after water pressure restored, otherwise I would've never seen the very fine spray out the crack in the elbow. I saw only continuously fresh wet area and the leak-spray was only visible with a flashlight in the dark.

Any thoughts appreciated. Thanks much.

 

[T444e]

Do I only need to replace only the 90* elbow?

Yes, but I would use a stainless steel elbow

Teflon tape enough for galvanized-to-brass fittings?

Yes

There's a backflow checkvalve already in place but it's 24 years old - any reason to replace it while it's exposed?

I don't see how that installation of the dual check is allowed by code as it is not accessible. I would check if having a vacuum breaker on the yard hydrant is all that is required and eliminate the dual check.

How did the 90* elbow crack? Freeze? It's at 24" below grade as per my local frostline data (Lexington, KY).

Are you sure it split? It may have failed from corrosion.

I would have replaced the yard hydrant with the stainless steel option Woodfird offers.

 

[Firebrick43]

If the pipe cracked and leaked soaking the soil the cold can be conducted further down the pipe.

Looking at historical weather in Lexington you did have a few days in the single digits.

2016 (if I recall correctly) I had a dribbling hydrant(wife didn’t tell me at the time) freeze down to 48” and crack fittings during a 5 day stretch of single digits. That was a fun one to dig up when it was so cold

 

[CraigStu]

I don't have the expertise to answer all your questions but this is my method of fixing plumbing problems.
I replace w/ new everything I can access.
I started this after a couple of repairs worked for a bit and then something failed upstream of my repair. Maybe I worked something a tad loose and didn't realize it. Maybe I put stress on something and didn't realize it.

 

[Bert_]

Yes, but I would use a stainless steel elbow


Yes


I don't see how that installation of the dual check is allowed by code as it is not accessible. I would check if having a vacuum breaker on the yard hydrant is all that is required and eliminate the dual check.


Are you sure it split? It may have failed from corrosion.

I would have replaced the yard hydrant with the stainless steel option Woodfird offers.

I've used some stainless fittings. They are about the same price as brass anymore. I hadn't even heard Woodford makes a stainless hydrant. Kind of wonder why? The regular Iowa hydrant will last 50 years.

 

[T444e]

I'm not a fan of galvanized pipe in most piping applications as superior materials are typically available. Woodford offers both a stainless and brass option. On a 2' bury depth, which i believe the OP has, the stainless is an $80 add at Supplyhouse.com, looked it up as I was curious.

In my experience, 150# threaded stainless fittings are cheaper than brass. But then again I'm typically buying from a supply house.

 

[Fav Onefour]

You are lucky. Our hydrants are a minimum of 6' bury. For that reason we don't mess around. If we're digging a hole that deep, we're going to fix stuff that might fail. I've also never seen a check valve buried next to a hydrant. Where is the line coming from? Is there another location along the supply line that is accessible?

The spray coming out of your elbow doesn't really look like a split leak. I almost wonder if that has been leaking for quite some time before the hydrant split.

We don't worry too much about drain fields around the hydrant valve. If it's below the frost line, you just want the water to drain your stand pipe. With heavy clay soils, we use more drainage rock. I've never seen silt fabric or filter used.

BTW, the attached hose thing is a big deal. The local hardware stores around here make a killing on frost free valves every year right after the first good freeze.

 

[k miller]

Update: Appreciate all of the replies. Mostly in line with what I was thinking but again, I have very little plumbing experience. Fortunately, I have a shut-off valve inside the house to just this line.

The leaking elbow is actually brass. There is a tiny crack that my 60 yr old presbyoptic eyes could not see even with reading glasses, but I can see it on zoomed-in photo. Still not quite sure of the implications ... frozen line split? manufacturing flaw? I remain mildly suspicious that the run of single digit temps we've had, combined with cold conduction ( I know - it's really heat conduction in the opposite direction ) could imply that my area's published frostline depth has a low margin-of-tweak in this particular application. I cleaned and dried the elbow, filled it with a small amount of water, and a very small leak became apparent.

 

[k miller]

And I'm thinking maybe the solution to avoid the (admittedly minuscule) hassle of disconnecting hose can be avoided by installing a double valved outlet on the hydrant between the hydrant and the hose. Just open the extra valve and break the column of water. No more siphon-effect. Though this approach still leaves the possibility of any hose itself freezing and splitting if enough water is left in it.

 

[Hank11]

Quick connects make it real easy to remove and re-connect the hose. Your default could become to always remove after using.

 

[k miller]

Quick connects make it real easy to remove and re-connect the hose. Your default could become to always remove after using.

Great idea and I’ve considered it, now that Ive learned my lesson. But it was actually a fortuitous mistake as otherwise I’d’ve not discovered that corroded hole in the standpipe until much later.

Unknown why, but I’ve never had much luck w quick-connects not leaking. Much like finding any pistol-grip nozzle that will last more than a year. Maybe it’s all made of Chinesium these days.

 

[acer66]

These are great and they also make a hd version with more metal involved but I never had an issue with the plastic ones.

Gardena is a household name over in Germany and also still make a lot of stuff there.

$10 at Home Depot.

 

[micromind]

Any galv pipe that gets buried, I always wrap with 10 mil tape. No rust........

 

[T444e]

With galvanized pipe, it not just the outside of the pipe that fails. However, I agree with using an additional exterior coating when buried.