Remove Radiator for Painting - what could go wrong?

trivetman

Having some painting done next week and I just thought about the potential of removing my steam radiators to give access to clean up the wall behind them. Seems simple enough as long as the nuts move. Am I a fool for trying?

The supply valves look relatively new. The return elbows may not have been moved in a century.

Steamhead

The return ells are brass, so they should turn. Don't force them.

I'm wondering if the bushing that the return ell screws into has a water seal built in. Can you take a pic looking straight at it?

Jamie Hall

Not much can go wrong — if you do it right and are strong.

First, the radiators detach from the pipes at the unions. The big hex nuts. Those nuts simply unscrew from the stud, which is threaded into the radiator itself. This leaves the valve at one end and the elbow at the other end attached to the piping, and there is enough wiggle to slip the radiator straight out from the wall.

Don't even think about undoing the valve or elbow from the piping. First, you don't need to, and second, there are any number of catastrophes which can result from the attempt.

The radiators are heavier than you think they are. Be careful when you are moving them that they can't tip over. They will try to.

When you go to put them back in, make sure that the mating surfaces of the unions are really clean — but do not use any form of abrasive on them. Some people use a little dish soap on the faces to make them easier to assemble, some use nothing at all — but they should never need any form of pipe dope or sealant. Make sure the radiator is precisely aligned with the piping, and then thread the union nut on. Hand tight, and then no more than a half turn with a wrench, if that. Do NOT be a gorilla — those nuts can crack and then you do have a problem.

trivetman

@Jamie Hall - I think this is what you're telling me, in that order.

@Steamhead

Is this the shot you want?

EdTheHeaterMan

You might want to reconsider the first statement about the radiator being a steam radiator. It looks like a hot water radiator to me.

So when you remove that nut at the bottom of the radiator, you may get lots of water to spill out. Which is not a problem as long the radiator is on the first floor and you dont have anything in the basement that may be damaged by water.

what could possibly go wrong here?

OR

you could drain the system of water before you attempt to remove the radiator.

trivetman

Ed - its definitely a two pipe steam system.

Jamie Hall

Yes. 1 and 2 are the two union nuts you want to undo. Be sure to try and turn them in the correct direction!

dko

Undo the smaller bottom nut first and then the larger top nut.

trivetman

Easy peasy. Both unions came off without any wrestling.

and surprise! This fell out of the return elbow. What is it? And more importantly, how do I orient it properly when I everything back together?

Jamie Hall

I thought you'd find that in the return elbow — or something very like it. That's one of a number of clever gadgets which were used to allow air and water to get out of a radiator, but not steam. It goes in, as I recall, with the flap thingy down. And the free opening towards the radiator.

That system is called a "Kriebel" system.

Now. That does tell me one other thing, though. Your system was designed to operate on VERY low pressure — what's called a vapour system — and to run properly it must be operated as it was intended to be operated. That means that the primary boiler pressure control needs to be a vapourstat, not a pressuretrol, and the 'stat needs to be set to cutout at 8 OUNCES per square inch, and cut back in at 4 ounces.

trivetman

@Jamie Hall

thanks. Ill look up the Kriebel system. Looks like theres some other posts which reference it.

you told me years ago in one of my first posts that a v-stat would help and putting it on was one of my first forays into DIY steam tuneups (along with putting a lot more venting on the mains) It did help tremendously with balancing things.

We put a new boiler in last year with about 80k less btu than the poorly installed monster we inherited. With the new boiler it runs a 45 minute cycle without building more than 3-4 oz of pressure so the vstat rarely kicks in.

Jamie Hall

Great!

Steamhead

The device in question is called a "baffler". Its job is to keep steam from backing into the radiator from the return if someone closes the hand valve. The Kriebel was one of the very few Vapor systems that allowed steam to reach the return lines.

You can find more about the Kriebel System in chapter 15 of this book:

https://www.heatinghelp.com/store/detail/the-lost-art-of-steam-heating-revisited/

trivetman

https://forum.heatinghelp.com/discussion/comment/1807290#Comment_1807290

interesting. I thought steam in the returns was a no-no as it could interfere with proper steam flow and balancing heat between all rads. What is so unique about the Kriebel such that steam in the returns is part of the design?

Mad Dog_2

Great discovery. That's a mini swing check valve. Make sure the flap swings freely and the hinge stays at 1 O' Clock.

Put some nice Teflon paste or any good pipe dope on the threads and a little coating on the face of the union when you reassemble the return and the supply, but don't let any get inside the pathway of the pipe. Mad Dog 🐕

Steamhead

https://forum.heatinghelp.com/discussion/comment/1807296#Comment_1807296

The steam was used to close a vacuum vent at the end of the dry return. From that point the system could drop into vacuum and generate steam at lower temperatures. This worked great on coal.

The Richardson, O-E, Moline and maybe a couple other systems did this too.