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Trying to Understand My Hydronic System

TaylorB Member Posts: 2
edited November 2021 in Radiant Heating
I have a home built in 1954, and the inspection tag for my Hydronic baseboard system is still intact with 1954 as the date of the install for the system.  The boiler is newer but cracked, not the issue I need help with.  I am wanting to drain the system remove the boiler and set it up for either a new boiler or a tankless water heater.  However, as I was trying to trace the lines and figure it all out, I found a line that goes to my Fireplace then comes back to the main loop. See drawing.  There are 2 circulating pumps.  One has its power connected to the boiler with a pump controller and an on off switch, the other has its own power source with an on off switch and controller.  Both pumps lead directly to the or through to the boiler.  The drain spigot with a valve below it just above the circulation pump.  The fireplace loop is connected to, what I believe is the main circulation pump which is before the Flow Control valve. If I wanted to drain the system or flush the system I don’t think it would work.  FYI the system has been off line for years  previous owner installed forced air with a heat pump. 


    EBEBRATT-Ed Member Posts: 13,450
    Looks ok you have 1 main pump and 1 pump for the fire place. As far as draining you just shut off the make up water and drain the system. Once the pressure drops a little you need to let air in the system somehow so the water will get out
  • mattmia2
    mattmia2 Member Posts: 7,752
    The loop in to the fire place probably went to some sort of heat exchanger where they were trying to extract heat from the fireplace, it sort of acted like another boiler.
  • mattmia2
    mattmia2 Member Posts: 7,752
    And don't use a tankless water heater as a boiler, get a real mod con boiler or a conventional cast iron boiler, a tankless water heater makes a poor boiler.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 5,650
    If there are any "Flow Control Valves" or Flo-Check valves in the system, you will need to open them manually. "Flow Valves" will keep the water from draining back to the boiler.

    This is from page 9 of a text is used to teach a one day seminar on Hydronics.

    The text can be found here: http://media.blueridgecompany.com/documents/ZoningMadeEasy.pdf

    This has a wealth of information on your system... and it is a pretty easy read.
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • TaylorB
    TaylorB Member Posts: 2
    It is a Flo Control  valve as noted. Thanks Ed.