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One stubborn radiator in a two pipe orifice (I think) system

I have a two pipe orifice system, at least I think thats what it is.  It uses what appears to be Richardson  calibrated valves for the inlets and absolutely nothing in the outlets.  No check valves, no traps, nothing!   Believe me I have taken the elbows apart and shined a light deep into the radiator.   Also there are one and sometimes two vents on the radiators.  Yeah its weird but seems to work on 9 out of 10 radiators.

My problem is one stubborn radiator.  There was remodel done in the bathroom by the previous homeowner and they moved the radiator a few feet and re-plumbed with copper. 

 I thought I found the problem when I discovered the original valve stem packing to be shot but I replaced and still no luck. After the replacement  the radiator barely gets hot for the first few inches and is cold at the outlet.   I disconnected the radiator and its not clogged.  Steam comes out of the supply valve.  I also tried just connecting the inlet and leaving the outlet disconnected to see if anything would happen.  My thought process is steam always flows from high pressure to low pressure but its still cold.  I then cranked up the pressure at the pressuretrol to around 4 PSI and let it run for awhile and still nothing.

Could my problem be steam volume?  The way the remodel was done I can't see where they ran all the pipes and I am at the point where I just don't think there is enough steam energy at the inlet.    Any suggestions?


  • First.....

    I'd check for proper venting of the radiator return main and steam main.  Then I'd remove the vents on the other radiators.    If you have too much venting on the radiators, steam will prefer certain radiators over others. 

    Boilerpro....Chicago and surrounding states
    The Steam Whisperer (Formerly Boilerpro)

    Chicago's Steam Heating Expert

    Noisy Radiators are a Cry for Help
  • Unknown
    edited February 2010
    Stubborn Radiator

    Edit: I wrote the following before I'd seen Boiler Pro's post. He is a very experienced steam pro and so I would suggest you follow his suggestions. What he says makes good sense.

    I'm not quite sure what to tell you. From your description it sounds like you have perhaps a combo of several systems early vapor systems.  With vapor systems (or any residential  steam system for that matter) ranking  up the pressure is going the wrong way and will do more harm than good. Vapor systems were designed to work on ounces of pressure. 

    If you're are wondering about ample steam supply, I'd just turn off all the other radiators to check that. You should then get plenty of steam going to just the one radiator!

    Since the other radiators are operating satisfactorily and the known difference factor with this one, is that it was moved and the inlet (and outlet?)  piping was changed, I guess the piping would be a good place to start. I think you need to test if there is steam coming into the radiator. If you aren't sure the radiator valve can be closed so that it shuts off the steam, you'll need to get a 1/8 inch pipe nipple and a small ball valve (probably a 1/4 inch ball valve as they are more common that 1/8 inch valve. Get a 1/4 to 1/8 reducer bushing so it will fit the 1/8 inch pipe nipple.) I've attached a picture of a similar setup that i use for testing radiator vents. You'll only need the nipple and valve.

     Once you have a good way to cut off the steam , the test is done  by removing the air vent  and using a strip of tissue paper held in front of vent hole (or the hole in the ball Vale ) Don't use your hands or fingers to teat fore air movement as live steam can give you a very bad burn!  Hold the strip by one end out of the way and place the other end of the strip covering the vent hole, Any air coming out will move the paper. Do this with test with the other radiators shut off as otherwise pressure may be coming up the return with them on.  If the paper moves, be ready to shut the valve so steam won't escape.

    If you don't get air movement I would then suspect that there is some sort of blockage in the steam line to the radiator. Is there a possibility that the valve is internally out of alignment or something like that?  Maybe it was taken apart and was reassembled incorrectly or has somehow slipped internally so the orifice holes now don't line up?

    I'm not quite sure how you can check this other than removing the valve and testing it in the different valve positions by blowing through it.   If you take the valve off I'd see if you can blow through the intake line. A vapor system runs on ounces of pressure so if you can't blow through to the main easily you have a problem.  LOL- Please don't do this with the system on or hot.! :)

    Let's see what you find out and then we can go from there.

    - Rod
  • 1dodson
    1dodson Member Posts: 13
    edited February 2010
    I have steam -- but is it enough?

    When I disconnected the problem radiator to check for a blockage I did open the inlet valve to check for steam.  You are right - it can burn!   LOL

    So I have steam at the inlet but I am not sure it's enough or high enough pressure. I hate to shut down the other radiators since I am afraid to mess with the position of those Richardson valves.  Some are a little tough to move and all my radiators seem happy. 

    Crazy question -- do you think I need a vacuum to pull enough steam in?   Could this be a vacuum system gone bad?
  • Follow Boiler Pro's Suggestion

    I think you're kind of "chasing your tail" at this point. Higher pressure, vacuum etc aren't the answer. If you don't already have it you might want to get "The Lost Art of Steam Heating" as this explains problems with high pressure and vacuum in detail.

     When I posted my reply last night I hadn't yet seen Boiler Pro's reply. My immediate thought on reading Boiler Pro's suggestion was, "Eureka! That really makes sense!"  I was going delete what I had written but since it contained some info on testing flow and not burning yourself, decided to leave it on line.

    Boiler Pro is a very experienced steam professional. It might be of help to you to read an article he recently wrote. While the subject is on a different area of steam, his comments about venting speeds on older coal fired systems versus "modern " approach is very interesting and applicable I think to your situation. Here's a link to his article:

    What I think I would do if I were you, is do as he suggests and check that the venting on the steam main(s) and radiator return(s) is working and is adequate. (You should have a separate vent on each main and on each return) This would be beneficial to do in any case.   Rather than removing the radiator vents at this point, you can just deactivate them by turning them upside down. This is a "win-win" situation as you can easily restore your previous configuration if the experiment for some reason isn't beneficial.

    - Rod
This discussion has been closed.