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System fluid capacity calculation?

CarGuy Member Posts: 19
<span>Hello, we will be filling our garage floor heating system soon (it is a closed system dedicated to a 40x40 detached garage). </span><span>Could anyone provide some insight as to how to determine the fluid capacity of a system with approaximately 1700 feet of 1/2" pex?  I ask as we will be using </span><span>the appropriate antifreeze at 50% (a product such as DOWTHERM) and I need to determine how much to buy for the mixing. </span><span> We are trying to find a supplier for the product in our area and I'd like to go in with some idea of quantity needed.</span> <span>Thanks</span> <span>Chris</span>


  • cattledog
    cattledog Member Posts: 60

    Wirsbo specifications indicate that 1/2" nominal inside diameter tubing contains .92 gallons per 100 feet of tubing.
  • meplumber
    meplumber Member Posts: 678
    50% is a little much.

    Unless you are in northern Alaska or Northern Canada, 50% might be too much.

    A 30% mix is sufficient for our climate here in Maine and keeps from putting too much strain on the circulator.

    Cattledog's information is dead on.
  • CarGuy
    CarGuy Member Posts: 19

    I'm in Southern Ontario Canada, similar climate to most northern states.

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