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Wet or Dry return

Small commercial apartment boiler. Underground return had been placed on the floor around the perimeter of the building. Yes it will be flushed out. The question is at what point is a wet return a dry return. The new boiler water line is 52” from the bottom of the pit and the return is 26” above the bottom of the pit. The Hartford tee is 48” from the pit floor. So they way I see it is I have about 22” of water above the return that is around the building. So i am pretty sure I won’t have a problem but my buddy insists on putting in a false water line.
The photos are of the old boiler so please just look at the return pipe that drops into the pit.

Comments

  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,564
    edited August 2019
    What is the height of the boiler water level from the bottom of the pit? As you know the water level in the wet returns rises and falls with the steam pressure. Lower ounces of pressure, controlled by a vaporstat, and verified by a good low pressure gauge will keep you out of trouble.
    I hope you are correcting the present “boiler-buster” supply piping with the new boiler so you are not back replacing this in a couple of years time.—NBC
    Ironman
  • Jamie Hall
    Jamie Hall Member Posts: 18,957
    Pay attention to @nicholas bonham-carter 's comment about the boiler piping. The present arrangement is guaranteed to damage the boiler with time.

    On the water line. What you need to watch is the elevation of your wet return at all the points where drips reach down to it in relation to the boiler water line. The wet return piping must be at least a few inches below the water line at all such points. If there is any concern, use an accurate level.

    From your description it sounds as though you are OK, although a boiler in a pit-- which is clearly a replacement for an older, bigger, taller boiler, is always a cause for caution.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • TitaniumHammer
    TitaniumHammer Member Posts: 8
    Yes I am going to correct and install a completely new header with a boiler that stands upright Peerless LC-06. The new water level from the bottom of the pit will be 48-50". The hartfordloop tee set at 48" and the wet return is 26" off of the bottom of the floor which will drop down to the pit floor and then come back up into the hartford tee. see attached drawing. Thanks
  • TitaniumHammer
    TitaniumHammer Member Posts: 8
    75" is to the lowest steam carrying pipe in the diagram
  • Jamie Hall
    Jamie Hall Member Posts: 18,957
    And you have, by your diagram, 53 inches from the water line to that pipe -- which is quite adequate for any reasonable pressure.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England