Hello, I'm in the process of putting the plumbing holes through the icf walls before the pour  and was wondering what size of a hole I should put in the wall for a potential geothermal unit?  I'm considering a six inch hole for my outdoor wood furnace pex plumbing.  Any comments appreciated.

ICF wall penetrations above grade or below grade?  If below grade, that single 6" penetration is going to be tough to properly water seal.

What size and type of loop field are you considering for that geothermal?  Vertical or Horizontal loops?  Close to the house or far away?  Header fused outside the wall or made up inside the wall?

In my case, I'm planning on a 3 ton geothermal unit with 3 vertical wells ~200' deep.  The wells will be ~20 from the house.  I will bring all six 3/4" loop pipes through the wall individually and make the header inside the ICF wall in my mechanical room which also has a floor drain.  I'm using six individual 2" SCH 40 PVC pipes for penetrations through my ICF wall.  When it comes time to seal the penetrations to the loop pipes, I will use 6 individual 2" reducing Fernco couplings to seal to the loop field pipes on the outside of the PVC penetration pipes.

See example below:

http://www.fernco.com/plumbing/flex...eeve-seals

For any hole you make, be sure to slope it downwards to encourage water to flow out.

If your house is going to use 6 tons or less, you could sleeve in 2- 2" sticks of PVC. This is what we use to protect our 1 1/4" headers from wall abrasion.
A house I'm bidding currently will have 2" headers so load can determine size of penetration.
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