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Expansion Tank Pipe Size

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152NP
152NP Member Posts: 49
in THE MAIN WALL
Can anyone tell me how to correctly size the piping connecting an expansion tank to the system?  I am currently installing a 40gal tank on a 130,000 Btu system. Water temp in the boiler loop where the tank will connect will be 190, and the tank will be charged to 19psi.. The tank comes with a 1 1/4 inlet, which got me wondering. I figured I better check with those than know more than be before bushing this down to 1/2 in to connect to a spirotherm. The tank is large to accommodate a three story building with cast iron radiators, and to work with a solid fuel boiler without using a dump zone.

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  • Mark Eatherton
    Mark Eatherton Member Posts: 5,875
    1/2" should be fine...

    The velocity of the expanding fluid will be nil.



    The diaphragm is made for he temperatures and pressure it will be seeing, so no benefit to running a larger pipe to dissipate heat before it sees the bladder.



    ME
  • 152NP
    152NP Member Posts: 49
    Expansion Tank Pipe Size

    Thanks for the info. That is what I thought, but sometimes what seems to make sense to me turns out to be wrong for some unforeseen reason. I figured it was best to check with someone when potential safety is involved.
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