I recieved my IGSHPA Installer certification almost 2 years ago with the intention of installing a system in my home. I have teamed up with a friend of mine who has 18 years of commercial and residential HVAC experience. We will be installing a 3 ton unit w/ horizontal loop in the coming weeks. I'm a Civil engineer and a Professional land surveyor with 13 years of site civil / construction experience. I've got a firm grasp on all the components involved in this installation and how things fit together. What I am lacking is some of the practical knowledge that a seasoned loop installer would have. My questions are as follows but what I am really hoping for is someone who is willing to give me about 10 minutes of their time over the phone to just clarifiy some things for me. Send me an email with your phone #. firstname.lastname@example.org. Questions: 1. When do you pressure test the line? My loop field will only require socket fused connections at the manifold and in the pipe leading from the manifold to the flow center. 2. My soil in this area is heavy clay. Should I backfill with some sand around the pipe to ensure proper heat transfer around the pipe. If so should I install some drip irrigation line above the sand to make sure it stays wet during extremely dry conditions? My trench is 6' deep with a pair of pipes on the bottom and a pair of return pipes at 4' deep. 3. Can you flush and purge the loop prior to installing the heat pump and then install the unit without introducing a bunch of air into the system. What fittings / devices are available out there to trap the small amount of air introduced by installing the pump in this manner. 4. Any other things you can think of that a first timer should know. I really appreciate anyones help. I just got laid off from my regular job the day before thanksgiving after being with the company for seven years. I am trying to make some things happen on my own without having to go on unemployment. Keep your fingers crossed! Thanks guys! Eric M. Lang, P.S.