radiator airvent failure

billygoat22

I've been hanging around this site awhile , picking up on some finer points of hydronics, and putting them to use at work. I'd like your advice on a question that came up the other day. Was replacing and old boiler with new and noticed several radiator vents were missing the adjustment caps off them, and recommended their replacement. (I'd rather replace them all,of course.)I checked the other vents with a pc of glass to see if they were leaking steam, and several left a small 1/4 spot on the glass and one left a 1" spot, so I assume that one is leaking. Just how much can a vent leak before its bad? Thanks

Steamhead

They shouldn't leak at all

change them if they do.

If they're relatively new and are already going bad, I'll bet the vents on the steam mains are either too small or missing completely. This overworks the radiator vents.

Measure the length and diameter of your mains and tell us what vents are on them. We can tell you what you need.

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billygoat22

Air vents

Main air vents are new, #75 Hoffman. The longer main is 2" pipe 20' long, the second about 15',( 2" pipe).Thanks for the help, I also directed the HO to a location to buy pipe insulation, they wanted to insulate the steam lines themselves. I've also looked over the sites you recommended and have a set of Audel's steam fitter boooks coming. I also took notes on the main air vent sizing thread going these past days and plan to look up some manuf sites for more info. Thanks again for your help.

Steamhead

Those Hoffman #75 vents

should do fine on those relatively short mains.

For more info on vent sizing, order a copy of Dan's "Dead Men's Steam School" video and workbook. The workbook contains charts you won't find anywhere else. And the video takes you thru the process of designing steam systems, with Dan at the helm.

I have those old Audel books- you'll love them too!

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