Noisy steam rads

Dave Gateway

We repiped the near-boiler piping, cleaned & serviced the system, checked all rads and eliminated all the system noise EXCEPT... First cycle every am, 100 yr-old 3-tube American Rads knock & ping for 1/2 hour and then not again all day. Otherwise, system runs like a clock. I'm feeling like the large rad tubes are amplifying what would otherwise be an acceptable noise level for an old system. I'm trying to avoid the trial & error route, and if we're looking at new rads I can sell it, but its got to work. Any HELPFUL suggestions? PS-I've eliminated the setback T'stat.

Ken_8

Change the offending rad's

air vent and down size it one full "step."



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bob young

knocking

try disconnecting radiator and draining . condensate may be trapped in radiator. had an isolated situation many years ago.. even though radiator had some slight pitch it was still loaded with condensate. drained it and problem evaporated

Steamhead

Three more things

1. Does the system have main vents, and are they properly sized?

2. Are the pipes insulated?

3. Is the boiler grossly oversized?

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Dave Gateway

Steamhead;
1. Main vents consist of a couple of 1/8" Gorton "D"s drilled & tapped into the 2 x 1 1/4" ells at the end of the 2 mains (dropping to 1 continuous wet return around the basement floor). They didn't seem to be the problem, so I left them in.
2. The mains are insulated, what little I can see of the vertical branches are not.
3. Boiler is your standard 30% oversized, as are the majority of boilers I come across in this area.
I kinda like Ken's idea about stepping down the vents, but of course the ones banging the most are in the baby's room and master bedroom. I don't want to find myself back there in the winter when they're too cold.

Steamhead

How Long

are those steam mains?

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Weezbo

This is also important aspect in sizing.... to valuable to let

Fade away in to oblivion...Steam head is asking a very sane question here.