Got around to running my elevations while it was nice out today. The basement floor is 1' foot above the pitless adapter. The static water level was 9" above the pitless adapter today with geo cycling on/off all day. The drain was ~4' below the basement floor at the riser pipe or roughly 3' below the pitless adapter. I have seen the static water level below the pitless adapter before but I don't know how much. It seems to occur in the summer during the dryer months. So now it does look like there is potential to siphon out of the well. The well is about 100 ft from the house and the drain where I took the elevation at is about another 100ft back out from the house. The first 100 ft of pipe from the well is only 3/4". I can make the rest anything I want at this point as long as I can shove it down 3" pvc pipe. So using all 3/4" line I will need to overcome 10ft of head just in piping at 4 GPM plus head for fittings, valves and the coil. Currently the geo uses a cheap irrigation solenoid valve. How would this behave under a vacuum? Doesn't it use the pressure on the upstream side to close it? Do you think it is possible to have 55F EWT with no pumping power? My other concern is how to overcome an "open" 3/4" line when the pump comes on if someone might exhaust the bladder tank while the geo is on. I know Eric showed me the twin pitless adapter but that would need another 100 ft line burried back out to the well but I agree that would probably be the best solution.
I like closed loop systems. The cheap valve should be OK. If you are worried add a vacuum breaker down hill of the geo unit. You need bigger piping. Mark
Well that didn't go very good. I picked up some SIDR15 3/4". I see now where the 3/4" HDPE is 3/4" ID the PEX is 5/8" ID. Anyway started to shove it down the pipe and I hit a snag about 20ft in. I ended up kinking the SIDR15 stuff. I have pulled the 1/2" pex up before to determine it has ~60ft of line down the pipe. I remember taking a while to get by one part with the PEX also. Almost like there is 90 that I run into. I eventually get the 1/2" pex by it (twice now). Wasn't so lucky with the HDPE. The pex is much stiffer and harder to kink. Is the SIDR11 comparable? I think with something stiffer I might have a much better chance to get by whatever I am hitting. Other choice is to float a string down the line and then pull a rope back up then pull the HDPE back down. Any way to stiffen back up a kink?