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Radiant heat control

I am an amateur trying to design a basic radiant floor heating system for one room in my house. I have a system 2000 boiler and currently have baseboards on one loop for my 1400 sq.ft. house. I installed this boiler used five years back and it has worked great. The house I took it out of had three zones, so it is still set up this way. I was planning to use one of these zones for the radiant heat. The room is approx 550 sq. ft. and square. I was planning to use two loops approx. 200 feet long under concrete. I know I will need a mixing valve and manifold, and want to keep it as simple as possible. The question I have is about the # of circulators. It is setup now for one taco circulator to run the three zones. Reading posts on this forum, I believe I will need another circulator to run the two loops. My question is what is the easiest way to add an additional circulator control. I do not want the loop circulator to run when the main circulator is running the baseboards only when the radiant heat is needed. Should I purchase a seperate controller or can I modify my current furnace control? When the furnace makes hot water it runs a seperate circulator with the main circulator so I know it may be possible.



Thanks for any help.

Comments

  • Gordan
    Gordan Member Posts: 891
    Why don't you start by...

    ...posting a picture, diagram, or both of your current near boiler piping layout?



    Is the room you're planning to heat with radiant, currently heated by any other means? Is your intention to use radiant as the only means of heating it?
  • Ironman
    Ironman Member Posts: 7,366
    That's About Half...

    The amount of tubing that you'll need if the radiant is your sole source of heat for the room. Have you done an accurate load calc?



    You'll also want to make sure you insulate underneath and the edge of the slab as well.



    And no, you can't modify the pump control. It can be added to, but not modified.



    Again, Pics of your current near boiler piping and controls would be helpful.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • amateur1
    amateur1 Member Posts: 3
    Pictures

    I have posted some pictures of my boiler. Radiant will be the only heat source. I am only going from memory but I believe I read I would need a 1/2 inch radiant tube every foot so I calculated 20 runs 20 feet long which would be two runs of 200 feet. This did not take into account the bends at the end so I would have to add 20 feet to each run. Does this sound far off? I got 2 inch rigid foam for insulation, r12.
  • Ironman
    Ironman Member Posts: 7,366
    Load Calc.

    The design phase is the foundation in any hydronics job. If the foundation's wrong, everything built on it will be wrong. The first step in design is an accurate heat loss calculation. This is not accomplished by "rule of thumb" or "I read somewhere". You must do the load calc. to determine what is needed in the way of radiation sizing. If you put insufficient tubing in the slab (which it appears you're set on doing), it will be wrong for as long as the slab exists.



    Do an accurate load calc. or hire someone who knows how and let them design it. You'll regret it if it's done wrong.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • amateur1
    amateur1 Member Posts: 3
    Control

    OK, thanks for the advice on running a heat loss calculation. I will start there. Any advice on a control system to add to my furnace? How about a book on radiant heating?



    Thanks
This discussion has been closed.