Wrench for tight space to remove union?

samurainstein · September 27

Hey there Heating Help,

I'm learning a ton about the radiant heating system in my home through this site, and tackling my first project that requires me to touch the system. I'm currently remodeling a bedroom, and need to pull out the base-ray cast iron baseboard radiators so I can redo the walls, floors, etc. I was able to drain all of the water from the boiler drain valve. Now I'm trying to remove the unions at the baseboard inlet/outlet. The piping is very close to the wall (unsion is about 1/2" away from the wall). My pipe wrench has no space to turn at all. I was about to run out to the store to see what my options are, but I figured I'd ask here. Is there a special wrench that you all use in these situations? Or maybe another approach that I'm not aware of to remove this baseboard? Images below for context. Please feel free to correct my language if I'm using the wrong terms. Thank you for an awesome, very helpful site 🙏

HydronicMike · September 27

I’d probably try pump pliers. Adjusted so the handles are just about touching. Then put a cheater pipe over it for leverage.
Or maybe vice grips with a cheater pipe.
The nuclear option is to carefully cut it with a sawzall and replace it.

EdTheHeaterMan · 12:10AM

First of all it appears that you have your pipe wrence set to tighten the union nut in your photos. the union nut rotation for that valve is to go UP on the side facing you and DOWN on the side facing the wall

If you don't have a flat jaw wrench that will fit that nut, ChannelLoc makes a thin jaw that opens wide enough for that nut. https://www.channellock.com/product/812swlg/

There are older flat jaw wrenches that were commonly used for that purpose.

This has a thin jaw to fit in that tight space. Some old man with an old tool box has one in his garage near you if you can find him.

Larry Weingarten · 12:19AM

Hi, It looks like a properly sized open end wrench or possibly crescent style wrench (as Ed showed) would do what you want. I'd also use something to hold the valve as you pull up on the nut.

Yours, Larry

hot_rod · 12:41AM

A basin wrench is another option

Crows foot

Flare nut wrench

PC7060 · 1:10AM

Take the knob off the cable to give yourself some room to work. Get a large crescent wrench as Ed and Larry recommended. I use a 18” wrench. Also, the threads are on the valve body so turn is opposite.

DCContrarian · 1:24AM

The tool you want is called an angle head open wrench.

Anything other than a wrench with fixed flat jaws will make a mess of the nut, it's soft brass. The angle head wrench has two heads, each angled and each at a different angle. Since you can flip it over there are four possible angles, one of them will work. You move the nut a little, then move onto the next head. After a bit you've moved it 1/6th of a turn and you go back to the first one.

A wrench in the size you need will be expensive in a brick-and-mortar store and cheap on Amazon.

hot_rod · 1:55AM

measure across the flats.

I've made open end wrenches from a piece of 3/8" thick flat stock and a porta-band saw.

Crow foot wrenches over 2" available

Jamie Hall · 2:06AM

All of the above. I'm not in favour of Crescent (adjustable) wrenches, unless they are very good quality. As @EdTheHeaterMan notes, the threads are on the valve part of the union, so you are pulling up and pushing towards the wall on the wrench handle.

Another wrench which would work — if the nut hasn't been overtightened — is a strap wrench like this:

CRAFTZONE Strap Wrench 12", Heavy Duty Adjustable Nylon Oil Filter Wrenches, Multi-Purpose Tool for Pipe and Tight Spaces: Amazon.com: Tools & Home Improvement

One of the handiest tools I own…

hot_rod · 2:17AM

The nut to floor dimension is what limits your wrench choices. A cresent that opens that large may not fit around the nut?

Tap around it with the two hammer method, or warm it with a heat gun, and you probably unscrew it by hand :)

samurainstein · 2:49AM

Wow, so many great responses and ideas! I came to the right place :)

@hot_rod you're correct about the nut to floor clearance. It's only about 1/4", so that's very limiting. For the two hammer method, can you point me to a link? or explain what that is?

Several ideas that I'll look into:
- Channellock slim jaw adjustable wrench
- 12" Strap wrench
- Open end wrench
- Angled head open wrench
- Crow foot wrench
- Flare nut wrench
- Basin wrench
- Pump pliers with a cheater pipe

I'll go to the store and check these out to see what feels feasible, or see if a friend has any of these tools. Another option, since I'm already doing this, is to take out the flooring and drywall first, to create more clearance around the nut, but I was hoping to just get the baseboard out before demoing the room.

EBEBRATT-Ed · 3:21AM

I agree with @hot_rod tapping a union with a small hammer will break the paint and rust loose and make it much easier to break loose.

Also the direction of the wrench as others have mentioned above.

a 12" adjustable wrench should do the trick along with some pump pliers when you get it loose.

109A_5 · 4:13AM

Unless you happen to find a super heavy duty Basin wrench I bet you will turn a common Basin wrench into a pretzel before you ever get close enough to loosen that nut.

I'd use this type of Crow foot, not inexpensive for the larger ones and you would need the long breaker bar too.

Or this, I think it would grip and spin the nut in the correct direction to get it loose. Then use the slip joints.

Wrench for tight space to remove union?

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