Steam Rad rises off floor

Thom18

Hi and thank you all in advance. I changed out a steam rad one pipe recently for a slightly smaller rad. Its the top rad on that 1 1/4'' line, its the end of the line.
Its got a number 6 air valve on it.
When I turn on the rad, shortly afterwards the main pipe rises upwards about 1/2 '' off tile floor and pushes/lifts the two feet nearest the shut off valve same amount off floor, Does anyone know why this is happening?
-John

Jamie Hall

It's expansion of the riser pipe -- but it's a bit unusual. Any idea how the other end of that pipe is anchored in the basement?

Thom18

Thanks Jamie, im not sure I can see it , it might be in side basement ceiling somewhere, My rad in question is on $th floor on top of riser. Does 1/2'' thermal expansion seem reasonable ? to best of my knowledge there was no similar issue happening with the old radiator

Thom18

4th floor

KC_Jones

You said you downsized, so the old radiator was heavier and may not have moved. That could mean you just have to live with it, or put something under the radiator so it's sits higher all the time.

Another possibility is some kind of piping issue. The steam pipes typically have joints arranged in such a fashion to allow the pipes to expand and not move things around. Swing joints go a long way to allowing for movement. It sounds to me like either the swing joints aren't there, or at some point someone remodeled in such a way to negate the ability of the swing joint to do it's job.

What you are seeing would not be considered normal.

mattmia2

If you can move the radiator 6" or so you could put a swing joint somewhere between the riser and the radiator. You would have to be careful that it still had downward pitch after the riser expanded. Did you by any chance change the valve to a taller valve or something like that?

Thom18

Yes I changed the shut off valve, I used a designer one pipe steam valve, fancy polished nickel. Im not sure its any taller. The new valve is sitting directly on top of riser. Im not sure but think the levitation of the radiator only happens when the valve is turned on. I don't believe it happens when the valve is off. Ill check that out,( that's important) but its rather telling if it does not happen when the rad valve is closed but the heat is on? Its a designer kitchen so I am limited on the extent of piping that can be used unless of course you guys advise me that more piping is the perhaps only and correct remedy.

KC_Jones

The piping won't heat much with the valve closed. It's the expansion of the piping across 4 floors that is moving the radiator, not really anything in the vicinity of the radiator. The joints I'm talking about would be on one of the floor below, and maybe even in the basement.

I didn't know they made nice valves for steam systems, I've looked many times and only ever found hot water.

Thom18

Thank u, Castrads make them. Its a co=op so access is a prob to some degree. Perhaps I will work on it when heat is on and leverage valve and pipe up to maximum from floor and secure it in that position with metal washers or otherwise beneath the feet. as suggested, if it cannot go back down that should be a safe approach ?

EBEBRATT-Ed

I would say higher is better than lower as far as pitch goes. i would put shims under the rad and let it go......see what happens

DanHolohan

The Dead Men would anchor a riser that high at its center so it would expand in two directions and not lift the top-floor radiator. They used screwed escutcheons on the 3rd floor (floor and ceiling). These may have been removed during a remodel.