I built a new building and went with geothermal. The contractor turned on the air handlers in June. The system has 6 air handlers totaling 20 tons and has 25 grouted 200' bore holes. The system is a single pressurized ethylene glycol loop with 5 circuits. We are able to hear air flowing in loop piping any time you get close to the loop pumps. The installer has been out 7 times now to re-flush the loops. The first couple of times he just spent about 3 hours flushing the loops, but the last few times he has spent between 8 and 9 hours flushing. The loop psi dose drop about 3 psi between flushes. I do know that I’m one of the largest installs that company has done. I have asked a few times about installing an air eliminator on the highest heat pump, but he says they lead to more issues than they solve. The list of excuses about the air in the system is to long to post. I'm thinking he needs to do a loop by loop flush (I think the last time that was done was in June). What are your thoughts on air eliminators? Is there anything else I should talk to him about?