Here's a diagram of my Loop Field...
...as you can see, I planned for more loops than I actually put in.
If I need to, I can add more loops in the future. There's even room in the front yard for maybe 6 additional loops. During the summer, I measured the pavement of the street in front of my house, and it was 145 degrees F on the hottest day. Some serious heat under that street, and with my name on it too!
I arrayed the boreholes as I did to get them as close as possible, like how honey bees arrange their cells. It allowed me to pack more holes in the space I have, but it really made trenching more difficult. If I had more space to work with, I would definitely put them in a grid pattern.
The hook-up sequence was arrived at because I wasn't sure how much pressure would be reduced by stringing all the loops in series. As I have it, I can cut in after the 8th loop and re-connect the field as two branches, each with 8 loops.
It's much simpler with one loop, but if I can't get the flow rate I want, I may change it in the future.
[EDIT (2015-04-22) the idea to leave the possibility off future change turned out to be very important. My total loop field pipe length was 720 feet, way too long for 3/4" pipe and required almost 1/4HP pump. I subsequently cut the loop in the middle which gave me two loops and it cut my pump power requirement by a factor of 4! (1/16HP), because I was able to get the same flow quantity at half velocity, and flow resistance increases (& decreases) by the square of velocity.]
Here's the loop field after trenching, before connecting all the loops:
I found that it really pays to run the trencher as close as possible to the plastic pipe, without hitting the plastic. Making corrections for a wide space (I had many) has been very time consuming.
Also the trencher threw the dirt up just over the edge of the trench and quite a bit fell back into the trench. The trusty Rigid shop vac was the perfect tool for clearing out the trenches and reclaiming those precious extra inches.
Here's Rhonda-the-Grandma, demonstrating good trench-vacuuming technique:
As I stated previously, I though I'd need to use barbed connecctors in the trenches, but later realized that I could pull the pipe up tight, weld the connection, working just inside the trench and then push the pipe in and cover it while holding it down with anything heavy (like large stones or my foot).
Here's a pic of the welding jig as I used it in the trench. I put a cinder block under it to hold it up. By tightening the hose clamps on one side of the jig and leaving them a bit slack on the other side, I was able to free up a hand which I'd then use to hold the fusion paddle.
After each weld, I'd let it rest for about 5 minutes, then I'd fill it up with water and gradually introduce air pressure to 90 psi. This should be done gradually, because if you hit the water filled tube fast, it gets the water moving pretty quick which can exert much more than 90 psi on the branch under pressure. I didn't do it, but I'm pretty sure that it would be possible to rupture a water-filled branch by pressurizing it too fast. I think this is referred to as "Water Hammer". I tested every weld, every time. Leaks were very easy to spot, water was spraying out of the few bad welds. Using a water bath method and looking for air bubbles to find leaks was out of the question.
Here is a pic showing two welds:
The top weld is a nice looking weld, the bottom one was done in a hurry and looks pretty crappy.
However, when I filled them with water and pressurized them, they both held just fine.
That's what really counts.
Best Regards,
-AC_Hacker
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