steam union direction

steam247

I understand union have a direction of flow, but what do you guys recommend on near boiler piping of a steam boiler. 2 inch steam pipe off header, should the union go in the direction of steam or the direction of returning condensate. it a 1 pipe system that is parallel flow, but i would imagine that some condensate still flows back down the supply. the union is installed on vertical pipe. 

EBEBRATT-Ed

This is a common old timer's tail. Put the union in any direction you want.

Personally, I try to locate them so that if there are any obstructions, I can get the pipe wrenches on to tighten the union. Loosening is less important to me.

Use common sense. Put your fingers in a union and try to tell which way the flow should go. It doesn't matter.

Further, I have never seen any code that says "put all unions in the correct direction with regard to flow"

steam247

ok thanks , also the pipe going to this union is very slightly cocked. to straighten this pipe out i will have to heat the elbow it’s connected too. i tried to turn it with 3 foot wrenches and got nothing.  i will also have to back it out very slightly to get it perfect. my question is do i take the chance and heat the fitting backing it out to level it or don’t mess with it because it’s not leaking and check first if the union don’t leak? don’t want to create more problems. 

EBEBRATT-Ed

I would not heat a fitting to try and bend it. If you post some pictures I can give you a better Idea of what to do.

Unions should be straight to seal properly but can sometimes take a very slight misalignment.

Used to be able to buy "Dart Unions" that had a smooth beavled face that the mfg said it could take some slight misalignment.

steam247

lol I look everywhere for a dart fitting can’t find. I don’t want to heat fitting to bend, was thinking have to heat the screw elbow to get it to turn. I tried with 3 foot wrenches and got nothing. or do you think it’s close enough. the old union had a  metal to metal seat. i believe that’s why it rusted and leaked over time. would have loved a brass to brass seat like dart, but no luck even looked on ebay. the new union i have is brass to metal seat 

steam247

to correct the pitch of that pipe i need to back it out slightly, to do that i need to heat and hope it turns. then hope i don’t get a leak from that elbow now. 

pecmsg

steamfitters classes said Male into Female. You don’t want the steam or fluid flowing into the male bevel. 

steam247

pecmsg i agree but this pipe has steam flow in one direction and condensate flowing in the opposite direction. which take president the steam or the hot water ( condensate) ? 

leonz

Is the boiler level from side to side?, maybe you just need a steel shim the left side of the boiler at both corners after you loosen the other unions?

pecmsg

steam247 said:

pecmsg i agree but this pipe has steam flow in one direction and condensate flowing in the opposite direction. which take president the steam or the hot water ( condensate) ? 

Steam can do more damage. Direction of steam is preferred. 

pecmsg

steam247 said:

lol I look everywhere for a dart fitting can’t find. I don’t want to heat fitting to bend, was thinking have to heat the screw elbow to get it to turn. I tried with 3 foot wrenches and got nothing. or do you think it’s close enough. the old union had a  metal to metal seat. i believe that’s why it rusted and leaked over time. would have loved a brass to brass seat like dart, but no luck even looked on ebay. the new union i have is brass to metal seat 

That alinement doesn’t look all that bad. 

JUGHNE

I would go for it, as it looks pretty good.
After it heats up you may have to tighten all of them.

And with a third hand if you tap on the large ring on a couple of flats while you tighten, you may get little more out of it.

pecmsg

Never Seize is your friend!

EBEBRATT-Ed

I agree with @ Jughne & @pecmsg never seize (any auto parts store will have it) and tighten it up it looks pretty good from what I can see.

If you have someone who can tap the union nut with a hammer while you put some pressure on the wrench you can get it real tight.

Intplm.

Been taught the common sense directions
Always tighten down. The pipe wrench tightens down. Union, nut side up to tighten downward.
Where the wrench fits to tighten down on the union nut is the way to go.
This can be the best way to get the most leverage to prevent leaks.
Anything else doesn't matter.

Mad Dog_2

I believe only in high pressure steam you might get wire drawing on the exposed lip of the ground joint.  In LP steam I don't believe its critical.  I GENERALLY install the Union with nut on top..its looks odd otherwise.  Also, lose the nut down a pipe in a deep wall and you won't do that again  Mad Dog