Leaky cast iron steam radiator, sections are uneven

davevarga

Now I realize this 100 year old medium sized cast iron radiator has been leaking steam (no water drip) between sections, which was the cause of the bubbling paint. As I place a straight edge on the top going horizontally and use levels, I can see some of the sections have dropped down. How to fix? The truss nuts were already loose. With the radiator standing, loosen the nuts up a bit more and carefully insert wooden wedges on the bottom sections and section by section tap the wedges until they lift the drooped section until they all are in alignment? Then tighten the truss nuts?

Jamie Hall

Can you identify which section joints are leaking? With any kind of luck, this may be the type of radiator in which the sections are -- or were -- sealed together by means of tapered nipples which rested in -- and sealed in -- equally tapered seats in each section. Very shallow taper, usually. It is not uncommon for older radiators to eventually have one or more of those nipples rust out, at which point the radiator will leak.

If you can identify which sections are leaking, the best approach -- often the only one which will work -- is to separate those sections and examine the nipples. If they are rusted through, one can have replacements made -- or at least one could at one time. I don't have the source handy. For that matter, a really good machine shop can do it. Then put them back in and put the sections together.

Sometimes one can get by with sealing the sections to each other with red RTV sealant, or some such and pulling them together.

Do NOT use the tie rods (your "truss nuts") to try to pull the radiator together. They'll break. They are meant to be just finger tight when the radiator is cold.

You can split the sections with wooden wedges -- working evenly top and bottom and front to back, although the automotive trade has some nifty gadgets for separating ball joints which work just fine. Just take it easy.

The best way to pull the thing back together is long pipe clamps. You'll need four, to make sure it comes back together evenly.

JUGHNE

Some leaks like that have gone away by lowing the working pressure. If so then a center support to keep it from sagging more might work.

Steamhead

@davevarga , how about some pictures?

davevarga

Hi All,

Here are some pictures but not very helpful... The radiator was more recently stripped and repainted with black heat paint. I found that there are 7 sections and at least five of them need to be vertically adjusted. Some adjusted upwards, some need to be adjusted downwards. Seems 1/16"

Jamie Hall,
I am going to guess that the sections that are leaking, and there are more than one based on the paint that had bubbled before I stripped and repainted it, are the ones that have slipped vertically from their adjacent sections. And if they have slipped like 1/16", if they have the nipple devices connecting them - the nipples might still be intact enough to take a minor vertical adjustment?

That was helpful about the tightness of the truss rod nuts, never saw that crucial information before you just mentioned it. But if I find that the integrity of the nipples is shot, even if I use RTV to rejoin the sections (after cleaning them), w the truss rods not being significantly tight, there would not be structural integrity to maintaining the sections being aligned.

Are nipples standardized for these wayback radiators? You would think these nipples would be readily available from at least one source.

Jughne,
Do not think to lower the vapor pressure is a solution, pressure is in spec.

Yep, thank you for this, to answer my above note to Jamie, a structural workaround could be center support, or even support for all the sections from underneath.

Steamhead,
I just did a visual inspection, not seeing open spaces at the bottom joints, that might be because of the repainting and the point might be clogging any slits? See Pictures.

Best,
Dave

Jamie Hall

That is an elderly raisdator... There won't be any nipples of the sort to which I was referring across the top -- and maybe not across the bottom, either. I think your best bet, if you're feeling brave, is to simply take one apart -- split it between any two sections -- and see what does (or did!) hold it together and prevent leaking. Then go from there.

On the tension rods -- once you do figure out what is supposed to hold the sections together, you don't have to worry about them being too loose, provided they are finger tight or just beyond (maybe a quarter turn on the nut) when you're done. There isn't much force there to pull it apart.

JUGHNE

Jamie, could those be left hand/right hand nipples across the bottom?

mattmia2

JUGHNE said:

Jamie, could those be left hand/right hand nipples across the bottom?

I doubt it because the non-connected end isn't drilled. It certainly could have all been assembled from the other end, but it seems unlikely given both the undrilled end and the rods.

davevarga

Jamie Hall
Elderly radiator, is that just saying it is very old or is that a special type/make of a radiator. I am not finding much on that term when I search the internet. From the way you describe it, it sounds like a certain type?
Best,
Dave

Jamie Hall

Good heavens no, it isn't a specific make. Just a word to mean "old". Like me.