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steam boiler problem

ClaudeD Member Posts: 2
I am dealing with 3 low pressure weil-Mclain steam boilers connected in parrallel. Each boiler was equipped with 2 probe type low water cut offs. boilers ran out of water and 4 low water cut offs failed to isolate the boilers resulting in cracked and leaking boilers. boilers were replaced and each equipped with one float style and one probe style low water cut off. My problem is since then when boilers are operating, water disappears in one boiler shutting it down with low water cut off backing water up in next boiler over filling next boiler. then repeats this with next boiler like a yoyo. Cycle last 1 1/2 minutes alternating from boiler to boiler


  • Jamie Hall
    Jamie Hall Member Posts: 21,117
    How are the boilers piped together? The near boiler piping?
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • KC_Jones
    KC_Jones Member Posts: 5,410

    How are the boilers piped together? The near boiler piping?

    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
    JUGHNE Member Posts: 10,581
    Is there a feeder pump for each or all the boilers?
    EBEBRATT-Ed Member Posts: 13,460
    Code rules state that "two steam boilers should not be connected together below the water line" If they are you need a check valve on each boiler (not the best way) or a hartford loop on each boiler.

    When you have boilers connected in parallel the idle (cooler) boilers will fill with condensed steam. The boilers that are running as soon as they build steam will try to force water out through there returns into the other boilers.

    To manage these water issues you need hartford loops, correct near boiler piping and and overflow (spill ) traps on each boiler.

    If you are using a condensate tank to feed water to the boiler this won't work either. A boiler feed tank may be needed with either feed water valves to each boiler or a feed pump for each boiler
  • ClaudeD
    ClaudeD Member Posts: 2
    I understand what you are saying. I will try the check valves on each boiler as this will be the most financial resolution. It still leaves me wandering how the system worked well for near 80 years piped exactly as it is only difference is a float style LWC.
    JUGHNE Member Posts: 10,581
    Is this a pumped return?