Anybody Recognize This Fitting?

[Erik]

Does anybody know what this brass 90 degree fitting is?

103613

It's 3/4 inch and it feeds an in-ground sprinkler system. Apparently, last year the company that winterized the system missed a spot and it blew out a section of the PVC piping and the ball valve just below this valve. I found out the other day when I went to turn the system on. I replaced the PVC parts today (ignore how sloppy it looks - at least my work doesn't leak) and now that the system will hold pressure, this valve is leaking from the right side, where that cross-bar looking piece runs across it. It looks like there's a plunger of some kind in there and there's a slow drip coming from it. I'm leaning towards this being a pressure relief valve or a check valve or backflow preventer of some kind, but I'm not finding anything that matches this image on line. I'd like to either replace it or rebuild it if it's serviceable. There's a local plumbing supply place that still has some old timers I can hit up this week if I can't figure it out but I thought maybe someone on the forum might recognize it.

Thanks

[EricP]

Looks like a check valve. The arrow indicates direction of flow. This would prevent the water in your sprinkler system from backing into the house.

[JohnO]

Looks like a check valve. The arrow indicates direction of flow. This would prevent the water in your sprinkler system from backing into the house.

Agree! Preventing the contamination of potable water.

[Erik]

It seems most likely, for sure. I'll have to take a closer look and see if it's serviceable because I am not finding anything like a direct replacement.

[MickAK]

It's an old ass backflow preventer.

I only know this because I once found one in an installation it was clearly not designed for and someone threw it in there, likely in a bit of a panic, and I had to repair it because it was holding up an inspection, in a bit of a panic.

Very fuzzily, it's supposed to leak water from the plunger thingy because it's supposed to have an air gap between the potentially contaminating water and the water being protected. Cleaning/lapping up the sealing surfaces stopped the leak in my case.

I don't know jack about building/home construction codes, but it's quite possible that it no longer meets code and you might want to just replace it. I'm pretty sure cleaning the sealing surfaces will require removing it entirely anyways, and if my fuzzy memory is correct repairing one is going to cost the equivalent of a new one in pain in the ass. But it might be worth a shot if it's going to screw up your fitting.

[Erik]

Thanks. I appreciate it. I'll have to see what it looks like inside when I get it out of there. Worst comes to worst, I wasted an afternoon and a few bucks on the fittings I put in today. Better to find out it's a problem this way and deal with it while it's only a pain in the ass.