Radiator Air Valve On Main in Basement

thepaulcee

Hi - we bought our 1940's home about a year ago (NYC). The house is a single story ranch. We have a gas fired boiler / steam heat.

Last year, I noticed a couple of our cast iron steam radiators were gurgling / dripping water, but it was minor and we made it through the winter OK. This fall, I had the stop valves and air valves replaced on those two radiators. Now, everything is working great and the heat actually is much quieter and more efficient.

However, I was walking by the basement door when the heat was on today and heard a hissing noise. When I checked downstairs, I found an air valve on top of a pipe in the corner of the basement. It was hissing steam straight out of the top, into the ceiling cavity space. This is right under the basement ceiling. See photo of the valve here.

Is this supposed to be venting air while the heat is on? I don't think this was happening last year. The air was hot but not burning hot, and if I held my hand on the air for a few seconds, I would get a little condensation on my hand. Just concerned that this is a side effect of fixing those valves upstairs. Don't want to damage anything if this is faulty, but want to make sure it isn't normal first.

Thanks in advance!

ethicalpaul

Unless it was happening during the first few minutes of firing, it was probably leaking steam, especially since you got condensation on you.

It's a "main vent" and you should replace it with a Gorton #1 or #2 or a Maid O Mist #1 if you want to save money. You want to replace it because it shouldn't be leaking steam. It is there to let the air out of your main quickly when the boiler starts producing steam so that the steam can get to your radiators faster.

After my response, people will ask you how long and what size of pipe your main is and they will try to figure out exactly which size you should get.

thepaulcee

Thanks very much for the reply. Definitely wasn't the first few minutes of firing, it was while the heat was fully on, and continued until the boiler was off (which caused it to slow in intensity and finally stop).

The main is approximately 30 feet long, I can measure the pipe size later when I get home. Our home is only a 1-story ranch with a basement so it isn't a very big system overall.

ethicalpaul

OK very good, then if I were you I'd definitely grab a Maid O Mist #1 and put that into service there. Advertiser on this site supplyhouse.com has them:

https://www.supplyhouse.com/Jacobus-Maid-O-Mist-J1-1-3-4-x-1-2-Main-Vent-Valve-3563000-p

But I see they've gone up from $18 to $28 which is only marginally less than the probably-more-highly-thought-of Gorton:

https://www.supplyhouse.com/Gorton-G14-Gorton-No-1-3-4-x-1-2-Air-Eliminator-Main-Vent-Valve-3522000-p

They are nearly identical. The connection to them is the same and is quite flexible, with both a 1/2" female and a 3/4" male thread.

thepaulcee

Great, going to order the Gorton! Is installation of these straightforward? Pipe compound and teflon tape?

ethicalpaul

Very straightforward, an excellent first steam project (it was mine too). I just use Blue Monster tape but you can use any tape and/or pipe dope.