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Wet underground return - why install a F&T trap???

elfie Member Posts: 266
have a vapor system with an underground return that connects to a condensate pump (pipe likely remains full of water and is not fully draining into condensate receiver)

there are no air vents, yet all rads are getting hot

seems installing a f&t trap would not be of <span style="text-decoration:underline;">no value</span> if underground return is filled with water

there are orafices on all the trapless radiators so by the time any steam reaches the end of the underground line it probably has been fully condensed.

end of main is also connected to underground condensate return pipe



  • Dave in QCA
    Dave in QCA Member Posts: 1,785

    Obviously an orifice system.  In a 2 pipe system, the venting occurs through the condensate return piping.  Is your condensate tank lower than the returns located in the trenches?  If so, that is the route that the venting takes on its way to  the tank, which is open to the atmosphere.

    If that is not the case, there must be some other way that venting is occuring.

    Curious, do you have key valves on the outlet of your rads?  if so, it is a Moline system.  If not, another type of vapor system.  Do you find any crossover traps?  probably not, since there are also no traps on rads. 

    F&T trap is approriate at the low end of a steam main, if it is being dripped into a condensate return line.  However, it sounds like we need more information and some pictures of your system.
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
  • elfie
    elfie Member Posts: 266
    condensate receiver piping

    here is a pic showing the underground pipe connection going into the receiving.

    you will also see another condensate return pipe joining the flow back to the receiver

    there is a slight upward pipe flow (see arrow) which suggests the underground pipe is not fully draining and other returning condensate from above can go both ways (ie. either to underground pipe or to the receiver)

    its an Arco model K system that we are trying to figure out (ie. when and why did they install the condensate pump) - the underground pipes have been dug up due to leaks and needed to be replace a couple times over past 10-20 or so yrs.

  • gerry gill
    gerry gill Member Posts: 3,078
    they probably installed the condensate pump

    because they didn't know what they were doing.
    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

This discussion has been closed.