fast failure of new air vents

fGbr56

I have a single pipe steam system in a 3-flat building in Chicago. A few days ago I bought a few Maid O'Mist #Ds for the third floor. For a couple days they worked fine but during the night they failed. One radiator just went stone cold. I've tried a number of different brand names of air vents but I continue to get these same results. It seems the issue has nothing to do with the brand name. Something else is happening and I have no idea what it could be.

Jamie Hall

What pressure is the system running at? Anything much over 3 psi peak makes vents very unhappy.

Waher

Sounds like the boiler pressure is set to high or you have dirty wet steam clogging the vents with debris.

Long Beach Ed

As the others have said, the boiler pressure may be too high.

If you are buying vents at a consumer store, consider buying a Gorton or Hoffman vent instead. We've found the Chinese ones commonly fail in a week if they work at all. We had a few that were even empty.

neilc

#pigtail

nde

The "stone cold" radiators sounds like the vent failed closed but could be a drop or so of water clogging the connecting nipple drain. If you take the vent totally out and shake it does water come out? Long burn runs or rads that fill quickly where vents open/closing can have this happen. Have not used mom but have seen this issue on hoffman 1as (think it is the tongue drain design was defective on some production runs).

I would try to set the thermostat to a fixed setting to see if that keeps the rad vents from cycling. In a properly sized system with good main vents and no thermostat swings, likely the vents will not even close or get over condensed with water. May be worth a try.