Panting steam radiators

DanHolohan

You're watching the steam surge toward the vent and then quickly condense, only to be followed by another rush of steam to fill the space formed by the collapsing steam. Insulating the pipes should help a lot.

Paul Fredricks_3

I've seen steam radiators pant in the past. Using a tissue, I watch the air come out of the rad for a second or two, then suck back in and repeat. The other day I saw radiators doing this, but they breathed in and out 3 -4 times per second. No insulation on the piping. Is this the reason for this fast panting?

ttekushan_3

panting

Hi Paul,

The panting is often due to a large section of missing insulation. Sometimes you won't see this if the boiler is large. On the other hand (just to complicate the issue), it usually doesn't occur (in my experience) without a complicating factor. For example, I looked at a "panting" system with missing pipe insulation, but also noticed that newer piping (actually several years old) was installed to replace leaking pipes. There was a bit more bounce to the water line than I was expecting to see on that make and model of boiler so I did a skimming, then had to resort to an eight(!) hour controlled surface blow off while the boiler was operating until the steam was dry. The result: the panting stopped entirely (the insulation was still missing) and the imbalance between the front and rear mains completely disappeared. The 10 minute lag on the second main's radiators decreased to 1 minute or so, and it was this second main that had the missing insulation.

I guess what I'm saying is that its a good idea to insulate the supplies, unless you are going to make someone angry for taking away their basement heat!

Bear in mind, though, that its often a steam quality issue. As a matter of fact I see uninsulated piping all the time but don't see this problem often. It usually shows up with a new boiler or piping repairs. Additionally, blowing off the controls or the boiler drain will never remove the oil film on top of the water. It can cause problems for years until another skimming or surface blowoff is done.

-Terry

David Nadle

Disappointed with cold skim

Terry,

Interesting post. I have mains and near boiler insulated, but not the takeoffs. I thought a little heat to the basement would be a good idea. But I am having some panting in the rads and I too think it might be wet steam and not uninsulated takeoffs.

I tried doing a cold skim, verry slow, maybe 2-3 gallons in about 5 hours. I think I just made things worse. Can you elaborate on "surface blowoff?"