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one pipe two pipe mix

blunder Member Posts: 3
I have an old new york city one pipe steam system in a low rise multi story building operating at up to 2psi and which is controlled by a heat timer system.

An engineer designed in two return air handling system to heat basement space. New steam piping was connected to coils installed in a horizontal position and control valves sized around 3.5psi drop. the new coils are within the zone A. A two position steam control valve was installed. The purpose was to isolate the air handlers from the building heating so that when the heat timer calls for building heat the valve would open. The boiler would fire to create steam when either an air handler control valve or heat timer would call for heat. The new control valve however shuts off the equalizer when in the closed position (due to pipe arrangement). No steam traps are installed on the new piping.

The problem is that the boiler floods. Looking for inexpensive effective fix (Rub Goldberg is ok). Converting to a pumped condesate return is not the answer.

I am thinking to add a small equalizer, raising the boiler water level and dropping the pressure a bit. will this work as the least cost 

Putting the system back to normal with either electric or hot water coils is an option.

Cant wait to here responses.




  • Steamhead
    Steamhead Member Posts: 14,326
    "control valves sized around 3.5psi drop"

    are going to be a problem. Steam systems are generally designed to run at one pound or less. That engineer was way off.

    Is there a valve controlling the main system or just for the air handlers?
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
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  • blunder
    blunder Member Posts: 3
    control valve

    There is a main control valve ( 2 position) that opens and closes based on a call for building heat. However , when it is closed the equalizer is shut off to the return (by nature of the project piping)
  • Charlie from wmass
    Charlie from wmass Member Posts: 4,166
    Then another

    equalizer needs added. do you have a photo or a schematic of the piping?
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • blunder
    blunder Member Posts: 3

    agreed. I probabaly need the proper size. I was thinking smaller, 1inch, to save cost.  the system will have 2 equalizers; upstream and downstream of the control valve.

    can get a picture or sketch
  • GermanPlumber
    GermanPlumber Member Posts: 44

    Hi Guys ,

    I don't do a lot of steam and have a customer who likes to ad one radiator . Can I run copper? Is ph in condensate too low for that ? Thanks a lot ! Mario
  • Charlie from wmass
    Charlie from wmass Member Posts: 4,166
    No you should not

    iron should be used for steam piping. ph is not the issue. thermo expansion is the problem. it can and does pop soldered joints. I have also seen soldered joints you could twist apart by hand after 10 or so years of service on steam.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
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