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Steam trouble waterlogged radiators

I have a steam riser that feeds three floors with radiators on every floor.
The top floor has two radiators connected to each other sharing one steam trap. Steam passes through and hits the first two columns of the first radiator but won’t pass through to the other columns and to the second radiator. 
On the second floor it has one radiator and steam just barely passes through the control valve and stops before hitting the radiator.
On the first floor it also has one radiator and steam passes though to the first two columns of the radiator and stops dead in its tracks.
I suspect that the condensate return line is not draining properly and has flooded the radiators but have no idea how to remedy the situation.
The condensate return line drops to a horizontal line into a main condensate return line returning to the vacuum pump.
Is it possible that the horizontal condensate line returning to the main line isn’t pitched for the condensate to drain properly to the main line.
The beginning season everything was running smoothly but I had to add city water and may have added too much. (Bad traps and FT traps all over building). Still trying to get this building under control and this one has me perplexed.
The adjacent rooms have steam with no problems returning condensate to the main condensate line which they share back to the vacuum pump.
I have bled the radiators before which temporarily fixes the problems but ends up getting water logged again.
I will try and figure out a way to pitch the horizontal condensate line but this one has me scratching my head.

Anyone else ever have a similar problem and or constructive criticism helps…

-Dazed and confused


  • Jamie Hall
    Jamie Hall Member Posts: 23,635
    You may have multiple problems. On the top floor one, how does steam and condensate pass from one radiator to the next? Unless they are connected both top and bottom, I'm not sure I can see how this would work reliably -- if at all.

    On all three, the first check will be to break the unions on the traps or take the trap covers off. There should be no water there at all when the system isn't running. If there isn't, try pouring a generous amount of water into the trap --a gallon or so. It should disappear promptly.

    Then if that goes well, check that horizontal -- if it can hold water (pitched the wrong way) it may be blocking air from leaving the radiators. That will do it too. The vacuum pump won't clear that kind of puddle out!
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • newschooloperator
    Hey Jamie thanks for your input. I opened the steam trap and noticed the vacuum was pulling toward the steam side and not through the trap side. I knew something was either stuck or closed, but could not figure it out.
    I went back to that horizontal condensate line that leads to the main condensate line. It has a gate valve that I’ve overlooked many times and assumed that it was always open.
    Today I pull the wrench out, gave it some elbow grease, and lo and behold it was closed shut.
    I opened the valve, the condensate passes through, and now I get heat on all three floors.
    I’ve had nightmares about this one and all it took was an opening of a closed valve.
    Kicking myself in the a$$ and patting myself on the back at the same damn time.
    Cheers until the next one


    Here is the two radiators piped into one steam trap. 

  • Jamie Hall
    Jamie Hall Member Posts: 23,635
    Glad you found the valve!

    You know, that arrangement of radiators just might work... if it does, be happy and leave it alone!
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England