Pipes to one Steam Radiator Banging in Nursery

Where are you located? We may well know someone who can help…

In the meantime, a photo of a radiator? I'm concerned about two things: first, the location of the vent— on steam it should be about a third of the way up the radiator on the end opposite the steam inlet, not at the top. Second, it shouldn't let steam out — air yes, but not steam.

Have we ruled out thermal expansion / contraction causing the pipes to pop as they slide against something?

OK — on that type of radiator, the vent needs to be exactly where you have it! Great! That's why pictures are important.

Now the drip — is probably from the valve, and you might take a really close look. If it looks as though it's coming out on the stem with the handle on, that's easy (yeah, right) to fix — you will see that the stem goes through a fairly good sized nut which is threaded onto the valve body. That's called the packing nut, and if you can find a wrench which fits, try giving it a bit of a turn clockwise and see it that helps.

And the radiator does need to be sloped wo that the valve end is lowest — I'd say at least a half inch lower than the other end. Depending on how it's hung on the wall, you may be able to raise the end with the vent on it enough.

Make sure that that valve is all the way open!

All that may help with the banging — but I wouldn't count on it. For top quality steam service, though, try @New England SteamWorks .

Are the other radiators in the system also that type or has only that radiator been replaced? That type of radiator will be more sensitive to pitch than conventional cast iron radiators because of its lower mass and smaller passages.

As Paul has said, the problem is the saging pipe in the wall. If you have access to the basement, you might be able to identify the pipe going to this very radiator and raise it ever so slightly to fix the pitch. At the end of the day this is not rocket science. If you have access to basement and can fix the problematic pitch = great! If not, the walls have to be opened to find and fix the pipe.

@mcmurphynora Mentions here that the radiator is back-pitched. He may be able to lift/pitch the radiator toward the valve so that condensate can drain properly. I would do that before opening the walls.

or if those hangers are sagging you could just wedge something under the far end of it. It is much lighter than a CI radiator but it still probably weighs 100#-200#

i bet those hangers are supposed to be installed at 2 different points horizontally in the top 1/3 of the radiator so but someone didn't read the instructions. There is a lot of rotational force on the hangers where they are now.

That radiator will act a lot different than a cast iron radiator. It will be more like a convector or fin tube.

Since the mass of the steel tubing is much less than a cast iron casting it will heat much faster so the steam will progress in to the radiator much faster, in a cast iron radiator having to heat the cast iron will make the steam progress slowly so it will be able to heat any water in the bottom of the radiator more gradually.

That tube header at the bottom is much smaller than the nipples between the sections of a cast iron radiator so the steam that is coming in faster also has less room to pass over the water in the bottom of the radiator without interacting with it or picking up a slug of the water when the steam collapses at the surface of the water causing hammer.

Fixing the pitch and putting a slower vent on it may make the hammer go away if it still heats adequately with the slower vent.

slowing down the vent can help make an issue in the runout somewhere less of a problem even if it doesn't actually fix the issue with water being trapped somewhere.

Same with mine, there was no difference between no vent at all, and a Gorton #4.