Two-Pipe Steam Radiator with Air Vent

miriamw09

Hi All -

I've been trying to get my two-pipe steam radiator system to quiet down for the past year, and I've recently realized that most of my traps have failed and need to be replaced. I had a plumber show me how to replace the trap, at which time he also replaced the air vent on the radiator. From what I've read, my system shouldn't need air vents, and that they were likely added to fix a different problem. Also, not all of the radiators have vents.

I'd like to replace the traps, install TRVs, and remove the air vents one radiator at a time, in hopes that the system will quiet down and function more efficiently.




Thanks for the help!

mattmia2

If there are traps in the system that are bad and passing steam, either on the radiators or between the mains and the returns, the steam in the returns will both block the air from venting out of any radiator it reaches before the air is vented and if it makes it to the outlet of a working steam trap it will close it from the outlet and prevent the radiator from venting or fully venting, so your bad traps may be the reason someone put vents on some radiators.(there are some 2 pipe systems that were designed to have radiator vents and there could be other unusual things about the design of the system).

Jamie Hall

But your system looks pretty conventional.

However -- a word of warning. Work around a little bit and try to identify all the bad traps and replace them all at once. Otherwise it really won't help as much as you'd like -- and there is a chance that bad trap B might damage nice shiny new trap A. Then set about taking off the air vents, which you won't need anymore (again, though, a word of warning. Make sure that you have more than adequate venting on the dry returns! That can get overlooked.) Then put TRValves on. They should well on your system (but get the system well balanced with the inlet valves first -- that's what the inlet valves are there for!)

PMJ

Yes, well filling a two pipe system so much as to need a trap to keep steam out of the dry return will be a noisy system for sure. The system I moved into was doing that, it was noisy and had vents on radiators here and there.

I decided it was dumb to ever fill radiators up with that much steam anyway. I don't allow that any more. I don't allow any air to go racing in and out every time the boiler fires either. That is a lot of noise for no reason. Now no trap is ever above room temperature because steam never gets near them. There is no air rushing in and out anywhere so there is none of that noise.

This is all pretty easy in 2 pipe if you are comfortable with some simple custom control. Feel free to PM me if you are interested to hear more.

Steamhead

@miriamw09 , it looks like you have a Vapor system. In this system there is supposed to be just one air vent, in the basement near the boiler (though some versions have vents on the steam mains as well) so vents on the radiators are not needed.

Can you take some pictures of the boiler and the piping around the boiler, as well as any vents or other devices you find there?

Also, where are you located?

mattmia2

Steamhead said:

@miriamw09 , it looks like you have a Vapor system. In this system there is supposed to be just one air vent, in the basement near the boiler (though some versions have vents on the steam mains as well) so vents on the radiators are not needed.

Can you take some pictures of the boiler and the piping around the boiler, as well as any vents or other devices you find there?

Also, where are you located?

I didn't look that closely at the valve. good catch.