A homeowner agreed on a job with a set price. There is a 4 ton and a 5 ton heat pump with 12 3/4" 700' slinkies on 36" pitch with a length of 125' installed at 6' deep with 15' spacing. The homeowner is refusing to pay saying that this is an inefficient system and not the "best". He says that pipe overlapping on the slinkies and pipe in the header pit is not acceptable. He doesn't believe any pipe should touch or overlap. The homeowner claims this system will not work in Central Missouri and that it needs to be trenched in or drilled. Keep in mind this is all after agreeing on the job and after the slinkies had been installed. What do you guys think? He also claims that heat pump manufacturers do not recommend slinkies and that pipe companies do not allow them because pipe will crimp and be worthless.