Hello again! OK, time for another question about our cheap-and-cheerful attempt to turn a 3 season greenhouse into a 4 season greenhouse, with the help of a 500 foot PE-RT loop. We haven't bought a GSHP for it yet, because I'd really like to test the loop first. As waterpirate suggested in my original thread (https://www.geoexchange.org/forum/t...ul-system-step-1-how-to-test.8233/#post-67749) we did indeed clamp a barbed adapter to each end of the PE-RT. I then attached one "100 PSI Air/Gas Test Gauge" (from PEX Superstore) to each end and pressurized the loop via the air chuck on one of them, to 50psi. Here's what the setup looked like: (please pardon my lack of photography skills) That was Saturday evening. This morning, we were at 10psi. Hmm. Wondering how much of that was the pipe stretching, I pressurized it to 54psi this morning - but by evening, it was at around 30psi. I realize that these systems are meant to be tested with water, not air, and I also realize that the chance of my having a leak in a system with no junctions should presumably be very low. I had tried to be careful about putting soft dirt (not rock) on the loop while refilling it. There had been one area that kinked, but I did straighten it out immediately; the next morning I looked at it and couldn't even tell where it had been kinked. I was still worried about it, so I called Oil Creek Plastics (who made the PE-RT) and spoke with an engineer there. He said it would probably be OK, but should perhaps be run at a little lower pressure - say 50psi. What do you think? Did I do more damage with that kink than I'd thought? Or is my connection between the loop and the test gauge maybe not as tight as I thought it was? Or is air just so useless for testing loops that there's no point in trying to interpret these results? Thanks in advance!