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Fixed orifice steam traps ANYBODY?

Mike20 Member Posts: 37
Has anyone had any experience with Fixed orifice steam traps?

 I am thinking about placing a bid on a Project to replace some 300 steam traps in a PRE-WAR apartment building in Manhattan that has some issues with live steam return to the Boiler.

My initial thought would be to simply change the guts on the ones that exist , or replace with exact replacement valves.

However the idea of a fixed orifice valve  sounds interesting as well like a very simple, maintenance free solution to the problem.

It also seems to be a new craze among those that are looking to save energy in their buildings.

I cannot find anything other than generic information online. And I cannot locate Information online regarding manufacturers or pricing.

Please let me know if you have experience with these valves and/or if you are aware of who manufactures  them.

Thank you for your assistance

Mike G.


  • jumper
    jumper Member Posts: 2,206
    flexitaullic ?

    Flexitaullic sticks in my mind. I think it was the company promoting what they called diaphragm traps in seventies or eighties. Another company to contact is GEM.

    Two issues to consider. Getting air out if air gets in to system. And maintaining a pressure differential. A flash tank or a steam water separator can do this with a terminal exposed to lower temperature. Like inside an otherwise unheated room.
  • MTC
    MTC Member Posts: 217
    From what I've heard

    orifice TRAPS were more trouble than they're worth, with getting clogged up and the like. Orifice VALVES seem to be a little more time tested, so you could look for an orificed valve setup to replace the existing valves, but I wouldn't do an orifice system in the trap bodies.

    If you want to do fixed orifices (orifice plates you install in the supply knuckle), Tunstall is the only manufacturer of them. You can send them your EDR ratings etc and have the size the plates for you, or just order a bunch of 1/8" plates and drill them out larger as needed. This will require a little guesswork and/or return visits to pull the plate from the union knuckle, drill it a tad larger, and replace it. It will also allow near perfect balance of the building, should you so desire.

    Make sure the system has very good vapor controls, as orifice systems rely on very precise, low pressure. If you do orifices, you'll need to open the traps on at least the rads that don't heat and remove the elements... they may be failed closed. Be careful, not sure how it happened, but I popped one of those babies open last week and the radiator was half full of water! Small fountain in tenant's bedroom... quickly pulled the element and let the remainder drain down the return line.

    Also, be sure to rebuild any F&T traps and the like in the system at the same time, or all your work will be for naught... you'll still get steam returning to the system. I'd do the F&Ts first, will help protect the new rad traps, if you go that route.
  • Mike20
    Mike20 Member Posts: 37
    Fixed orifice steam traps ANYBODY?

    Thanks for your help

    I was going nuts about it

    I like the idea of the fixed orifice on the inlet even better than the outlet

    seems like even less chance for screw ups and clogs

    I appreciate the benefit of your experience

  • MTC
    MTC Member Posts: 217

    I should mention that failed closed traps are very much NOT the norm. I only found 1 out of 35 or so I was replacing that day last week. And from what I hear, its kind of unusual to have any failed closed.

    So, what you can do is just abandon the traps in place. The ones that still work will serve as a nice backup to the orifice system. The ones that have failed will almost always be failed open and not cause you any problems.

    You can just do all the orifices (and especially take care of all F&T traps etc that could allow steam into returns), then fire up the system, and see if a rad doesn't heat after that. If not, there's a good chance the old trap is failed shut and it needs to be removed. The rest you can just leave alone.
  • jumper
    jumper Member Posts: 2,206
    different animal

    Orifice supply is different from labyrinth trap. Should not be done by fixed price bid. There's trial and error involved. Undersize to begin with, and increase in rooms reported to be cold. Eventually building is balanced, everybody is pleased, and fuel consumption has decreased. Success of these surprise me, because load distribution can depend on time of day and on direction of wind.

    An aggressive gutsy guy can bid low, and stuff trap housings with boiled non-rust steel wool. Please don't use my name if you do that.
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