Vapor System with a Return Trap and Air Eliminator

Kenny

We have an old steam vapor system that has the Dunham 9A
return trap and a Dunham 220 B air eliminator with an air
check. The problem is that steam is coming out of the air
check. I have never seen any parts breakdown on any of
these items. Does anyone know what is inside of the air
check, what can be used to replace it,or what the piping
schematic would be if you removed all of these and install
a condesate receiver.
Right now we have a piece of rubber cut and placed inside of the cap of the air check to prevent any more damage from the steam. .
Any help that you can provide will greatly appreciated.

Thank You
Kenny Allen

Christian Egli

Save the Dunhams

There is probably nothing wrong with the air eliminator. I wouldn't say it is meant to stop steam, it is there to keep a liquid (the condensate) from going where gases go to the outside (that's the air, but steam is also a gas).

If steam is coming to this part of your system, I would check all the radiator thermostatic traps.

It seems you have heap loads of steam coming out, I think it might be a cross over trap from the steam main to the return. One of them failed and is wide open.

It is the thermostatic traps that are supposed to keep the steam out of the return system.

Dunham made thermostatic traps, I am guessing your system has them.

Note, with the rubber plug, your air will have no place to leave the system, and with the air clogging the pipes, no steam will go anywhere else. It won't work long until the homeowner becomes angry.

Beyond that, nothing (almost) can go wrong with the return trap. It is basically a pump-less condensate pump. Replacing it with a condensate receiver and pump is no improvement.

Hope I helped. If there is no thermostatic traps, let us know what kind of orifice type valves you have.

Steamhead

I couldn't have said it better

Kenny, to locate the bad trap, feel the dry (overhead) return line. There should be no steam in this line at all. Find the return branches that are steam-hot and follow them back to the radiators (or end-of-main crossover traps). This is where you'll find the leaking traps.

Dunham is still in business, as part of MEPCO. You can get replacement parts for your traps from them, or from Tunstall (www.tunstall-inc.com) or Barnes & Jones (www.barnesandjones.com). The latter two have online catalogs. Any good supplier should be able to get what you need.

If you have "The Lost Art of Steam Heating", your Dunham system is covered in chapter 15. If you don't, order your copy on the Books and More page of this site. To locate a steam professional near you, use the Find a Professional page of this site. If you're in the Baltimore area, contact me.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Christian Egli

The good steam, bad steam routine

Dear Steamhead,

Reading your posts is always better than watching the usual police and detective drama. Ooh, the way those steamy branches need to be tracked down... I am thrilled you liked my contribution.

But I am most proud that I got here before you. Not by much, you'll note, but still, for just this once.

It's all for a good cause.

Good luck Kenny, and Dan Holohan's books are indeed worth it. Bestsellers.