Considering 3/4" HDPE x 4200 lineal feet per 8' deep for 6 ton system. Contractor says 7 ton loop field for 6 ton will increase efficiency 30%, and keep the electric heat assist from coming on until ambient temperature is at 12 degrees outside. Water table is at 7' maximum year round, higher during spring. Doing 600' per ton plus extra for the said above. Any other considerations I should know ?

Posted By GreenAnythingDotNet on 29 Nov 2013 09:25 AM
Considering 3/4" HDPE x 4200 lineal feet per 8' deep for 6 ton system. Contractor says 7 ton loop field for 6 ton will increase efficiency 30%, and keep the electric heat assist from coming on until ambient temperature is at 12 degrees outside. Water table is at 7' maximum year round, higher during spring. Doing 600' per ton plus extra for the said above. Any other considerations I should know ?

Not true. Increasing the loopfield by 15% will not increase the efficiency by 30%. I would say 3%, if at all. I like large loopfields, but the entering water temp might go up a couple degrees, if that much. It will also not ensure that your balance point, where you need supplement heat, is changed significantly. That is only determined by the capacity of the unit, not so much by increasing the entering water temperature.
Again, I like large loopfields, and always oversize them slightly, but it certainly does no accomplish what you have been told.

I agree completely.
Larger loop field do have benefit, but it is NOT by any means a 30% increase.

OK..

How is pressure testing done after the lines are laid (before buried) and heat fused to test for leaks ?

Loops are installed, fused together, then PSI tested.
We test ours at 30 psi, then 60 psi, then 80 psi for 20 minutes before backfilling.

Screw in some fittings with a compressor pipe into the PE, pressurize it, see if it holds the pressure.

OK. Wonder if any garden hose couplings will work on 3/4" also. How often do you find leaks in these pipes after install ?? Almost never ?

About 1% of the installs. I had a hole in the pipe coming from the manufacturer, and I had 2 fusion joints leaking.

Got to install 8 - 800 ft loops with no connections. Should just be able to pressure test them all in coils ?? Or will the unraveling produce any manufacturers flaws ?

Posted By GreenAnythingDotNet on 08 Dec 2013 11:44 AM

Got to install 8 - 800 ft loops with no connections. Should just be able to pressure test them all in coils ?? Or will the unraveling produce any manufacturers flaws ?

Now you are up to 6400 ft? There is usually a vacuum seal in the pipes, so when you cut them open, you should hear if they are sealed and tight. What do you mean by "no connection"? Do you plan to header it inside?

Excuse me, 6 - 800 ft loops. 4800 feet total.

No connection: 400 out and back each loop.

Yes, header with manifold flow center immediately inside the basement.

Is it OK to send 6 loops (12 lines when done laid) next to each other for the first 130' to the loop field or does it defeat the purpose ? Better yet, could I dig two trenches from the house and put all the "Returns" and "Supplies" pipes in each respected trench ? How exactly could it be worked ?

Posted By GreenAnythingDotNet on 08 Dec 2013 07:51 PM
Excuse me, 6 - 800 ft loops. 4800 feet total.

No connection: 400 out and back each loop.

Yes, header with manifold flow center immediately inside the basement.

Is it OK to send 6 loops (12 lines when done laid) next to each other for the first 130' to the loop field or does it defeat the purpose ? Better yet, could I dig two trenches from the house and put all the "Returns" and "Supplies" pipes in each respected trench ? How exactly could it be worked ?

As long as you keep them 1' apart, you would actually get some heat transfer out of it. If you don't have the room, run 3 lines out at 8' and another 3 at 5-6'. Same with the return lines for the 2nd trench.

Would it be easier to lay 6 slinky loops ? An how do they calculate lengths out of 3' overlapping loops ? Would there be any efficiency loss ?

If this is your first install, keep it simple and go with straight pipe. One side of the trench out, the other side of the trench back. What size bucket do you have?

12,24, & 36" buckets.

Would u consider doing this if I provided the materials?

http://www.geoexchange.org/forum/threads/lots-of-confusion-with-quotes-and-designs.5758/page-4

You do realize Docjenser is in Buffalo NY?

Chris

No.

Some people like to travel.

it seems to me that you are over thinking this. If you know how much pipe is needed. just dig the trench and put it in.

Looking for a good pattern for my layout that's least invasive.