header in side is more work. That is the only drawback that i see.

Access to the header and its connecting loop pipes might allow quick determination if one or more loops is for some reason not participating in heat exchange.

As an engineer, I always want access to more data. That said, once a loopfield is dialed in and purged of all air, it shouldn't need much attention or access.

I'm planning on having my header in the basement mechanical room. 3 tons, 3 vertical 3/4" U-tube loops ~250' long (~200'-220' down the holes which will be just in front of the house). I'm going to install six (6) 1-1/2" PVC sleeves through my ICF basement wall and bring all of the 3/4" lines into the basement through the sleeves where they will be terminated to the header.

Arkie, that's what I was considering. Have you verified 1-1/2" is large enough for the bend? Don't know how pliable the tubing is and wouldn't want any kinks. Would you install the sleeves when the basement is poured and later excavate to feed the loops into the mech room?

Engineer, I'm with you in wanting access. I'll discuss with potential installers before making decision. Perhaps an expansion of your tag line...

There are no problems, just solutions
There are no solutions, just alternatives

Inside or outside the choice is a installers prefrance.  I have also found it to be regional/union affected.  In central and north Jearsey for example they have a strong pipe fitters union and all piping goes inside to be headered.  I drilled a fourteen ton job in central Jearsey and when I went back later to see the resedential mech. room, it was better than some commercial projects I have been on!

There won't be any significant bends in my loop pipes when they enter the basement. I'm going to install my sleeves ~18-24" below grade level (anything >12" deep is frost protected here). The sleeves will be installed in 3 pairs, one 8" above the other for inlet and outlet so the inlet and outlet headers will all be in a horizontal line. This will be ~4' high inside my mechanical room. And yes, the sleeves will be installed before digging any of my loop trenches. I also have ~3-4' of overdig on my basement wall right now so I have plenty of room work outside the basement wall for installing waterproofing and such.

Most folks around here that header in the house do so because they don't trust their work or they are using other than fusion to connect the pipe.
One could have access to a header without it being in the basement.
By the way, if you "prefer" vertical because of the  "more efficient argument", don't.
In this instance "more efficient" means less pipe in the ground not lower operating cost.
Good Luck,
Joe

I would prefer vertical (1) over a pump and dump because the water here is pretty hard and (2) over a horizontal closed loop because the soil type here that requires periodic soaking via some joint buried water hose.    

Where else could the header be other than buried or in the mechanical room?  Or are you saying access is by digging up the buried header?  

Although based on what I've read in this forum and others that vertical can be somewhat more efficient than horizontal, I'm not basing my preference on that alone.  Maybe I just don't want a football sized excavation project to cleanup.  

Current Man J says 4ton system so say 4 loops.   Run from undergound header to mech room is about 35 ft.  So extra length would be 3 loops x 2 tubes/loop x 35 lf = 210 lf.    How much would an extra 210 lf of tubing  affect operating costs? 

Headers can be placed in vaults or large valve boxes depending on the design.

Thanks Eric. Now that you mention vaults/boxes, i recall seeing this done on large commercial projects. Ever do this on a residential project? Dave

I personally would never do it on a residential project,  but there is no reason why you could not if you want your system done that way.  Alot of horizontals get headered up in vaults and boxes due to the diy installer not trusting there fusion or balancing or to bring together a lot of loops for a bigger project.

We header inside whenever possible, It just seems to make good sense. I have made hundreds of fusions inside and out without a single failure. I certainly trust my work.

How much would an extra 210 lf of tubing affect operating costs? If you were able to give each loop its own trench, you would see an increase in efficiency rather than a decrease

HOH, Assuming a dedicated trench per loop, how do you configure the supply and return line? Side by side separated by 18 to 24"? Or one at apprx 6' and the other at apprx 4' depth?

I should expand on our house plan which consists of a single storey ICF with a slab on grade doubling as the finish floor. The mech room will take a roomy corner of the garage. So if we were to header inside, the loops or conduit for future loop installation would have to be done about the time we did sub slab utilities, right? Is this getting the horse before the cart? Looking at Arkie's plan above, is 1-1/2" conduit big enough for the loop tubing? Dave

Either is fine.

Thanks, the Metraflex looks like a sturdy seal.

I'm planning on extending my PVC sleeves far enough outside the wall to install a Fernco coupling on it to seal around the loop pipe.  These are readily available and fairly inexpensive.  Those Metraflex seals look to be high $.

Fernco Flexible Pipe Sleeve Seals

For sealing all through penetrations and sleaving we use Baroid Benseal. 12.00 50# bag. When mixed spairingly with water you get a pliable, non drying hydraulic seal that I have never had seap or leak.

Yes, you would definitely need to plan ahead and place your sleeves before pouring concrete.  If you are coming up through the slab, you will also need to get through or under the footing.    All of this needs to be decided on and put in place before you pour any concrete.

3/4" SDR 11 HDPE is a common size pipe used for vertical geothermal loops.  This pipe has an OD of ~1.050".  If you used the larger 1" SDR 11 HDPE loop pipe, it has an OD of ~1.315".  Unless you have very long loops, the 3/4" pipe is generally preferred for better flow turbulence and better heat transfer.

Standard 1-1/2" SCH 40 PVC pipe has an ID of ~1.590", thus it could be used as a sleeve for either 3/4" or 1" loop pipe.

If you have any concerns, just use 2" PVC pipe sleeve which has an ID of ~2.047".    This is large enough to accommodate 1-1/4" SDR 11 HDPE header pipe with an OD of ~1.660".  If you have to make any bends or sweeps in your sleeves to get through or under a footing, using the 2" PVC pipe might make more sense since it would be easier to push the 3/4" loop pipe through the larger sleeves if there are any bends involved.

Fernco makes a flexible pipe sleeve seal that will work with either the 1-1/2" or 2" PVC sleeves and 3/4" or 1" HDPE loop pipe, part number DTC 110 for the 1-1/2" sleeve or DTC 210 for the 2" sleeve.

http://www.geothermal-heat-pump.com/products/HDPE%20pipe%20and%20fitting.html

http://www.harvel.com/pipepvc-sch40-80-dim.asp

http://www.fernco.com/plumbing/flexible-couplings/pipe-sleeve-seals