Best way to tighten union?

Dave_61

I noticed the radiator in our bedroom is dripping water from the brass nut on the left of the picture. It’s such a tight spot. I tried a monkey wrench and couldn’t get it around the connection. A spammer wrench wouldn’t really grab. It is so close to the floor. Is there a specific wrench I can use to get in there and tighten it? Any other tricks? Thanks Dave

mattmia2

You might be able to slide a pipe wrench over the top of the valve and tighten the nut on the wrench after you have the jaws on union nut.

An open end wrench might work too, the different offsets as you flip it over might give you enough angle to turn it enough to grab it with the offset turned the other way after you turn it.

pecmsg

Dave_61 said:

I noticed the radiator in our bedroom is dripping water from the brass nut on the left of the picture. It’s such a tight spot. I tried a monkey wrench and couldn’t get it around the connection. A spammer wrench wouldn’t really grab. It is so close to the floor. Is there a specific wrench I can use to get in there and tighten it? Any other tricks? Thanks Dave

Open it. 
Make sure it’s aligned properly. 

Lightly sand the mating faces. 

A little never seize on the faces and a touch on the back of the nut where it turns. 

Smooth faced pipe wrench jaws. 

hot_rod

Two of my favorite, try to use the smooth jaws as @pecmsg suggested

EdTheHeaterMan

Dave Said: "I noticed the radiator in our bedroom is dripping water from the brass nut on the left of the picture. It’s such a tight spot. I tried a monkey wrench and couldn’t get it around the connection. A spammer wrench wouldn’t really grab. It is so close to the floor. Is there a specific wrench I can use to get in there and tighten it? Any other tricks? Thanks Dave"

A spanner wrench, AKA open end wrench, has a 15° offset that allows for a total of 30° of turning a nut until a blockage renders it to stop. Upon stopping due to an obstruction, the wrench can than be flipped to use the 15° offset in the opposite direction to grab the next set of flats on a hex shaped nut. Turn another 30 ° until you reach the obstruction and then flip the spanned again to use the 15° offset in the opposite direction to get another 30 turn on the same flats of the hex shaped nut, thus achieving a total of 60° of turn on each flat of the hex nut.

In the world of professional repairmen, that may be somewhat expensive for just turning a nut 1/6th of a turn. In the world of DIY, there is no substitute for owning the proper tool.


Further advise: to stop any Spammer from sending you unwanted emails by using a Spam Blocker in order to reduct Spam. I'm not sure if it will work on Spammer Wrenches.

Jamie Hall

Couple oof additional thoughts -- I'd not sand a union's mating faces, though I might and have polished them -- nothing coarser than 400 grit. Any scratches or grooves and you're done.

The other thought is this: unions, to seal, must be aligned very nearly perfectly, both left to right and up and down and angularly. They can and do pull together pipes provided they the ends aren't separated by much distance, but they can't compensate for misalignment.

If the pipes are properly aligned, however, they should seal with no more than half a turn after finger tight. A little more torque won't hurt much, but shouldn't really be needed.

The solution to a dripping union isn't a bigger wrench. It's taking it apart, making sure the surfaces are very clean, making sure the alignment is right, and putting it back together.

Larry Weingarten

Hi, One more thought is that if you put a couple of turns of teflon on the threads, the union will be lubricated, so it can be tightened further and with less force than if no lubricant were used. This trick has helped me with stubborn unions for a long time.

Yours, Larry

random12345

I always thought you were never supposed to put teflon tape or pipe dope on union joints...

Larry Weingarten

Hi @random12345 , Agreed. I'm only suggesting using it on the male threads of the union to allow for better tightening.

Yours, Larry

random12345

For lubrication to prevent spalling? Makes sense but why do people keep telling not to do it then?

Larry Weingarten

Hi, I think we're not supposed to get teflon between the mating surfaces of the union itself, and I don't. I use teflon for lubrication and to make the joint much easier to disassemble later.

Yours, Larry

109A_5

Hello @Dave_61,

You could try a Crowfoot. However one that size may be expensive and / or hard to find.

random12345

Larry Weingarten said:

Hi, I think we're not supposed to get teflon between the mating surfaces of the union itself, and I don't. I use teflon for lubrication and to make the joint much easier to disassemble later.

Yours, Larry

Makes sense. Thanks.

SteamingatMohawk

Some times, because of settling changes in the house the piping can become misaligned. If the joint was disassembled, when retightening, I have found that rocking the radiator can help get a tighter connection. I can't determine if that is possible with your layout. Good Luck.

SteamingatMohawk

Also, for unions that are threaded to the pipe, tape or dope can be used at those threads. The mating surfaces of the threadpiece and tailpiece are where nothing should be used. See the sketch. The red line is the mating surface that we are referring to that does not get anything on it.

JUGHNE

Some brass nuts are not standard wrench sizes.

Have you considered a small chain wrench.

That is if you have room for the chain to go around the nut.

The chain wrench could come in handy for a lot of uses later.

Dave_61

Thanks for the advice. The nut is about 2 3/4”. So, I did raise the end of the radiator a week or so ago because it was knocking when heating. It was not tipped toward the valve. I hadn’t loosened the connection. If it were already tight, could raising the end 3/8” cause the connection to leak?
I was able to snug it up a bit with channel lock pliers. Thought it was good. When the heat came on, it started dripping like crazy. Turned it off. 

EBEBRATT-Ed

I agree with @JUGHNE . A small chain wrench that you can put a pipe on the handle would be the best way out.

No one is going to go out and buy huge open-end wrenches for 1 union.

I would take the union apart and clean it up, load it up with neverseize and tighten it up

EBEBRATT-Ed

Yes. raising the end of the rad likely caused the leak.

When you tighten the union put some pressure on the wrench to tighten it and with a hammer tap the union nut in several places while you put pressure on it you will get it much tighter.

Don't smash it just light raps

Dave_61

Thanks Ed. So a chain wrench can be used on the union nut? I thought a chain wrench was only for round surfaces like pipes. And if I put the chain around the nut, where would you want me to tap with the hammer?

Jamie Hall

Miscellany... First, undo the union completely and make sure that the mating faces are clean and smooth. Then, with the nut still slipped out of the way, bring the mating halves together -- slide the radiator just a bit, perhaps. Now look at what you have: do the mating halves come together straight on? No lateral or vertical misalignment? No angular misalignment (same tiny gap all the way around? If not, do whatever needs to be done to correct the alignment, Now put a thin film of something like dish soap -- or a VERY thin even film of something like neverseize, and perhaps a wrap or two of Teflon tape on the threads -- but that's not for sealing, just friction. Now thread the nut on hand tight, and then certainly no more than half a turn with a wrench. Yiu may find that you can get it a little farther on by "helping" it by rocking the radiator slightly while tightening.

Be careful not to overtighten. More muscle will not give a better seal -- but may very well split the nut, and then you do have a problem.

Dave_61

hot_rod said:

Two of my favorite, try to use the smooth jaws as @pecmsg suggested

I ordered one of each as I won't know which will fit between the nut and the floor. It's such a tight space. Both straight pipe wrench and crescent wrench wouldn't work.

PC7060

I use large channel locks. You can get in smooth jaw configuration.  

ChrisJ

@Jamie Hall You can certainly sand the sealing surfaces of a union if you want it to leak.

pecmsg

ChrisJ said:

@Jamie Hall You can certainly sand the sealing surfaces of a union if you want it to leak.

With a Brass union there nothing wrong with "Lightly" sanding the mating surfaces. We did it annually on steam control valves.
All your doing is taking away minor imperfections. A light coating of never seize, hand tight maybe a 1/2 turn and done.

ChrisJ

pecmsg said:

ChrisJ said:

@Jamie Hall You can certainly sand the sealing surfaces of a union if you want it to leak.

With a Brass union there nothing wrong with "Lightly" sanding the mating surfaces. We did it annually on steam control valves.
All your doing is taking away minor imperfections. A light coating of never seize, hand tight maybe a 1/2 turn and done.

When you want two metal surfaces to seal, I'm not sure how dragging sharp boulders across them is supposed to help the situation.

@JakeCK Does your shop work with such metal to metal mating surfaces and how are they typically handled?

mattmia2

If I were going to buy something the chain wrench vise grips probably would be my first try.

Dave Carpentier

Would it be worth lowering the rad end back down to its original height before loosening the nut, or could that open up a new can of worms ?

SteamingatMohawk

@Chrisj As I read @Jamie Hall 's comment, I took it to mean he was referring to dish soap or neverseize on the union nut and/or threadpiece threads, not the mating surfaces of the threadpiece and tailpiece.

ChrisJ

SteamingatMohawk said:

@Chrisj As I read @Jamie Hall 's comment, I took it to mean he was referring to dish soap or neverseize on the union nut and/or threadpiece threads, not the mating surfaces of the threadpiece and tailpiece.

Jamie was responding to @pecmsg's earlier comment.

I understand and agree with the intent of the antisieze, pipe dope etc on the threads.

SteamingatMohawk

I know, but I don't believe @Jamie Hall was advocating using anything on the mating surfaces.

Jamie Hall

SteamingatMohawk said:

I know, but I don't believe @Jamie Hall was advocating using anything on the mating surfaces.

No, I would never put anything on the mating surfaces. For one thing, they don't move relative to each other (you hope) so there's no need. Second, they should be very smooth. If you do use something to remove imperfections (but not scratches -- scratched you're pretty much done) never any coarser than 400 grit.

Larry Weingarten

Hi, I wonder of some parallel jaw pliers might help here?

Yours, Larry

JakeCK

ChrisJ said:

@Jamie Hall You can certainly sand the sealing surfaces of a union if you want it to leak.

With a Brass union there nothing wrong with "Lightly" sanding the mating surfaces. We did it annually on steam control valves. All your doing is taking away minor imperfections. A light coating of never seize, hand tight maybe a 1/2 turn and done.

When you want two metal surfaces to seal, I'm not sure how dragging sharp boulders across them is supposed to help the situation. @JakeCK Does your shop work with such metal to metal mating surfaces and how are they typically handled?

Most all of our fittings are metal to metal sealing. How exactly that seal is achieved is dependant on the type of fitting.

That said those surfaces can certainly be polished. How polished it needs to be really depends on the fluid inside and how big or small the atoms or molecules are. Even a mirror finish is pretty rough if you look at it under high enough magnification. 

Intplm.

This might get you there

.

Don_175

An offset pipe wrench should fit in there.

hot_rod

The soft pot scrubber pads work well also. They conform to the shape, are not aggressive and add a dollop of dish soap for some grease and oil cutting

Big Ed_4

Over the year a mechanic would collect odd ball pipe wrenches just for a union like that .. I would recommend lubacation on the union threads to remove resistance . Pipe dope would work . I have tighten unions like that using a pipe wrench in reverse ,locking the pived of the jaws ...

Dave_61

Thanks for all the advice. I am waiting on my offset wrench and will then update my post once I tighten it. Do you think I should just try tightening first or just bite the bullet and take it apart and then retighten? Thanks

Jamie Hall

Take it apart, clean it, and then retighten. @hot_rod 's suggestion of dish scrubber pads is perfect -- that's what I use.

Dave_61

Jamie Hall said:

Take it apart, clean it, and then retighten. @hot_rod 's suggestion of dish scrubber pads is perfect -- that's what I use.

OK. Cool. And when you mentioned some soap, just on the threads? Absolutely nothing on the mating faces?