Slowly leaking steam main union

malex

Hi everyone,

I have not been on the site for a few years after i followed the great help tips on this site, so after I insulated all pipes, but in a good amount on main venting and turned down the cut off pressure, things have been working adequately well (the occasional hiss and bank is i guess almost unavoidable).

But i noticed rusty water stains on the bright white main pipe insulation so I took it off and there seems to be a small leak from the bottom of a union. There are few other take offs but only the union show any signs of leaking (it's, not dripping, there is only a little gleam of moisture on the back of the union - not the threaded side - where the nut meats the pipe.

Note, it is a very small leak - i do not need to re-fill the boiler ever (except after blowing out the LWCO).

Do i need the professionals to come out on this one or is there a way to seal the union

?

Jamie Hall

I probably wouldn't worry much about it -- but if you have a big enough pair of wrenches there'd be no harm to seeing if you could tighten it a bit. Don't be a gorilla, though.

malex

Thanks Jamie - good to hear it's not a big concerns. Tried tightening with a 20" pipe wrench but it did not move (i didn't go gorilla on it though for fear of breaking the pipe. Probably need a bigger wrench with more leverage). But i'd like to cover it back up with insulation without it becoming a soggy mess again - is there any thing that can be put where the leak is? Jb weld for example?

JUGHNE

Does your LWCO have an auto fill device attached?
If so you could be losing more water than you think.
I had one of these only hardly dripping and after the repair the water usage dropped dramatically.

New England SteamWorks

I think if it made the insulation soggy it should be addressed. Nothing to put on it. It just needs to be tightened with appropriately sized pipe wrenches. Where are you located?

lchmb

I like to take them apart and clean them then use the appropriate amount of force to seal the leak..:)

Jamie Hall

lchmb said:

I like to take them apart and clean them then use the appropriate amount of force to seal the leak..:)

Well, yes. That is what should be done. It is a large enough union that it may take some persuasion, though. Always use two wrenches! And, on a main like that, it wouldn't be a bad idea to make sure that both ends are adequately supported...

malex

Jughne: I have an autofill but its disconnected - as I mentioned, I do not add water unless i blow the LWCO. Havent done it for ~2 weeks and the level is right where I left it.

RI_SteamWorks: I'll take your advice and will have it addressed with big wrenches. I am in Long Island. And maybe soggy was not the right word but the isulation sleeve was water stained and the insulation looked like it had been soggy but it was dry when I took it off.

Jamie: there are three take offs in close proximity that effectively is holding up the main as the ends rest on the sill. But ill look into adding a clevis hanger or two to make sure the union is not stressed.

Thanks all.

lchmb

sometimes helps to hit it with a hammer while someone pulls the wrenches....not trying to break it..just shock it...I also have been known to do that while tightening....just not as hard...

EBEBRATT-Ed

Best way is to take it apart and dope it with "never seize".

@Ichmb is correct about the hammer trick..... works every time.

The only thing is the unknown. You might fix the leak or make it worse. Need to be prepared

If you attempt this yourself you might wait for warmer weather in case you have problems.

john walsh_2

I've had better success at getting troublesome unions to seal when the steam is up and the union is steam temp. You just need to use extra caution not to get burned.

jumper

If you go with epoxy I recommend that you apply it when joint is hot.

Jamie Hall

jumper said:

If you go with epoxy I recommend that you apply it when joint is hot.

Epoxy? Where??? Not on the faces of the union! They must be clean and smooth.

Larry_52

Go with what Jamie and Ed said. I would loosen it first, follow Ed's advice of never seize on just the union nut threads then try and tighten. If that does not work open and inspect the seated surface. If it is cut you could use permatex #2 on seat for a "temporarily" permanent repair. Technically the seated surfaces should be lapped together to repair, but that is more expensive then replacing and that case either way you have to remove.

malex

Thanks for the good advise. Will definately wait for warmer weather in case it becomes a bigger repair.

jumper

Jamie Hall said:

jumper said:

If you go with epoxy I recommend that you apply it when joint is hot.

Epoxy? Where??? Not on the faces of the union! They must be clean and smooth.

Agreed. I meant that if OP decides not work on joint but instead to goop it. A good goop can work. A bad goop is very not nice.

j a_2

My thinking is the union just didn't start leaking cause it loosed up..I think you have a pipe rusted out...Get yourself a 2 inch nipple run thru 6 in. and a union...Cut out the nipples clean the female threads and reassemble with new nipples and union....Be done with iy