Coaxial Exchanger PSI drop?

Discussion in 'Vertical and Horizontal Loops' started by heatoldhome, Jan 1, 2015.

  1. heatoldhome

    heatoldhome Geo Student Forum Leader

    I've seen some of the recommendations for pump sizing on this forum, None seem to include the PSI/ ft hd drop in the heat exchanger.

    I'm wondering why? This is part of the system, and water has to flow through it also.

    I cant find a listing for Climate master, or Bosch w2w units psi drop in the coaxial exchanger.
    With the help of Google I found a 3ton coaxial exchanger that lists 4.4 PSI drop at 9 gpm or a little over 10 ft hd. This would make a big difference in the actual GPM flow if you did not figure this in.

    Are all coaxial exchangers the same? is it safe to assume a 3ton w2w GSHP has a 4.4 psi drop at 9 gpm?

  2. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    They are all very close. I will see if I can get you real numbers.
  3. dgbair

    dgbair Just a hobby Forum Leader

    Andy, it's in the document for the unit (in the performance charts)... The way the actual flow is measured on a unit is by taking the In/Out PSI and then looking up the gpm on the unit's chart. So given a unit, you know your target gpm, so you can see what the PSI delta should be.

    Looking at a older CM doc, 3 ton unit... EWT at 30 degrees; 9 GPM == 5.7 PSI or 13.1 ft

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