3" union leaking

1Matthias

So, one of our neighbors has a 3" union from 1899 that is spewing steam and water due to a failed gasket. Should it be replaced entirely, or would it be practical to make a new gasket out of teflon or similar? I've attached photos.

Kahooli

If you can cut those bolts and get it apart they sell gaskets every day. $5 or so. Use new bolts imo...

https://www.zoro.com/search?q=flange+gasket&variants.attributes.3599=3"

EBEBRATT-Ed

That is a "flanged Union". It doesn't take the same gasket as a companion flange.

You can cut the bolts off and pry it apart to clean and scrape, but looking at the pictures that has been leaking for a long time. You can get gaskets for them.

You could use a red rubber gasket and it would probably seal but the gasket won't last very long. A non asbestos gasket is better but may not seal if the flange has damage

Chances are the flange is pitted or has a steam grove worn in it by now and the whole thing needs replacement, but you wont know until you get it apart

GroundUp

Flange union as was mentioned above. You'd need to see how bad the damage is to the face of the gasket surface before determining whether or not the gasket can simply be replaced. Replacing the whole union on a system that age may be opening a can of worms, but can sometimes be done. We've done a number of replacements by cutting the old union into thirds with a cutoff wheel in a grinder and breaking the last bit with a hammer to avoid marring the pipe threads, but have also had quite a few worn so thin over the years that any stress from a wrench or otherwise will destroy the pipe. If you are able to replace the gasket, I would recommend a non-asbestos gasket (coated with anti-seize on both sides) and new B7 studs. Good luck!

jumper

I'd try some sort of goop before I'd mess with it. I've had success sealing water under pressure with quality epoxy and glass cloth. Thermal cycling may be problematic but what is there to lose?

Fred

I had to replace one of those flange unions about three years ago. Gasket was leaking. I had sealed it with epoxy that lasted about two years. You really have to get it super clean for the epoxy to bond but it will eventually leak again. A fiberglass gasket can be purchased for a few bucks but in reality, when I got the bolts out and tried to clean the surfaces of the union, they were so pitted that I had to replace the entire union. They can be broken fairly easily, but expect to maybe have to replace one or both of those nipples as well. Always remember Murphy's law, and Smith's theorem (Murphy was an optimist). Be sure to buy the correct replacement bolts when you buy the new flange union, as well. Regular bolts will stretch too much from expansion and contraction.

1Matthias

Ok. The union is going to be replaced entirely. I'm tempted to post the rest of this install to Heating Hell though... It's a complete disaster.

New England SteamWorks

Put me in the "replace it all" camp. If it's worth doing, -it's worth doing right.

1Matthias

@New England SteamWorks I'd love to replace it all, but considering the circumstances, I'm probably only going to be able to replace the union and main vents currently.

New England SteamWorks

Actually, I meant replace the entire union and two nipples, rather than trying to fit a new gasket.

I haven't seen the rest, so have no opinion about that.

1Matthias

@New England SteamWorks Ah, ok. New union is definitely in the works. Photo of install attached. EDIT: This was done by the same guy who did our install. This one was done 17 years ago, and the union has been leaking for that entire time. It's a miracle that the boiler hasn't rusted straight through.

EBEBRATT-Ed

Nice!

1Matthias

Yep. On top of that, the main vents (3 amazingly undersized Hoffman 4As) are all fountaining water and steam, so that doesn't help either.

Danny Scully

We’ve seen that open legs header design before wallies! Who is this ceral killer?

1Matthias

Hey, at least this one leaves room for expansion as opposed to the install we have...

jumper

New England SteamWorks said:

Put me in the "replace it all" camp. If it's worth doing, -it's worth doing right.

Who pays for your time? When it's me I consider short cuts. (But then I'm not as skillful as some of you guys)

If OP can get bolts loose,he can clean up and jam some packing between flanges.

1Matthias

So, I discussed it with the neighbors. When I talked to them, they declined to even try fixing it in lieu of replacement. They would rather do it once and do it correctly instead of futzing about.

Larry Weingarten

Hello, After removing the bolts, try heating the flanges hot with a big torch. Then they should be far easier to unscrew. If not, you get into slicing them up as Fred said.
Yours, Larry

Fred

Replacing the entire flange is the right thing to do.

Fred

It's too bad, since you have to replace that flange joint anyway, that you can't repipe that boiler correctly and also eliminate that bull Tee, at that flange, as well, and drop each half of that main into the new header.

1Matthias

@Fred Yeah. I'd love to fix it, but a) after 17 years of an insane amount of intake water...I'm leery to touch the boiler, because with my luck it would crack the instant I brought a wrench into the basement; and b) they can't really budget for a repipe at the moment. We'll see though.
Side note, technically there are 3 mains. The 3" pipe going into the wall bullheads somewhere in the crawlspace, turns into 2 separate mains, and comes back via 2 different returns.

Fred

I was concerned about the age/condition of that boiler. I guess replacing the flange and vents will have to do, for the time being.

1Matthias

Yeah. That union was already leaking when it was replaced 17 years ago, but the installer didn't want to fix it, and instead "fixed" it by installing an automatic water feeder (!) after they complained that they were having to add water every time the boiler came on (!!). After 17 years of this... it's a miracle it isn't rusted through completely.