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Idle steam boiler: how to maintain water level? (Bob Morrison)

> a 3/4" F&T trap into the header drip just above <BR>
> the waterline and drain the trap into the <BR>
> feed-pump's receiver. <BR>


  • Bob Morrison_3
    Bob Morrison_3 Member Posts: 54
    Two steam boilers, one idle: how to maintain its water level?

    Given two headered, lead-lag, low pressure steam boilers, what are methods from preventing the idle steam boiler from overfilling from condensate from the in-service boiler?

    One method would be to isolate it with an automatic control valve on its steam pipes, but that would be expensive. What are other ways?

    Thanks in advance.

  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 16,490

    a 3/4" F&T trap into the header drip just above the waterline and drain the trap into the feed-pump's receiver.
    Retired and loving it.
  • Spill Trap

    Put a tee on your equalizer(s) at the maximum height you can stand for a water line in the boiler. Pipe a 3/4" F&T trap there, with a gate valve to throttle the inlet, and VERY short nipples. Pipe it to the feed tank, or the wet or dry return.

    Use schedule 80 nipples there. The erosion goes through them FAST. I have no idea why.

    Much nicer climate here, Bob. Got snow?

  • Bill N.
    Bill N. Member Posts: 18
    Make sure you have same elevation waterlines

    Otherwise, you'll probably want to use a MD 150 set up to act as a high water cutoff. For example, if you have one big old boiler and a nice new boiler next to it with different elevations of waterlines and common feedwater piping (ie, one pump with many solenoid valves on the feeds) then you might want to worry that the big boiler's waterline might drop right into your smaller boiler and fill it up.

    Bill N.
  • Bob Morrison_3
    Bob Morrison_3 Member Posts: 54
    yes, you've got a better climate and better pizza!

    thanks, guys!

  • noel, can you post a drawing of that spill trap

  • Edward A. Carey
    Edward A. Carey Member Posts: 48
    Idle Steam Boiler

    Dan is on point with his suggestion of using the trap in the drip header. I am not saying that just because he is our host here. I have done it several times in the past, and it has worked well.

    BTW, one of the places where I used the trap method to unload overfill from and idle boiler and return it directly to the condensate reciever, was in the main building of Penn State University, Wilkes Barre Pa Campus. I installed 2 commercial Burnham boilers there, about 20 years ago. As far as I know, everything still working well.

    That building is a large mansion that was donated to PSU by the family of a mutual friend of ours, Donald (Jammer) Cuningham, of Eastern Penn Supply Co, (EPSCO), in Wilkes Barre Pa.

    I have known Don since I started in the business, aprox 32 years ago. Don is a friend, and he is an asset to the HVAC industry.


    Edward A. (Ed) Carey
  • Yes

    Let me make one up, now.

  • Noel, what would be used to control

    the on/off of two steam boilers set up this way? would that be a two stage t-stat? just curious
  • in this case,

    it was a college admin building. The radiators had TRVs and the boilers ran at and below 65° F. outdoor temperature.

    The boilers both had hi and low fire, so I had four vaporstats staging the boilers and the lo/hi fire on pressure.

    In the spring and fall, one boiler would do the job. In cold weather, the second boiler would run.

    The system was built in 1911, the boilers are about 10 years old.


    The boilers had individual feed pumps from a common tank. MM 150 water level controls ran each pump.
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