Hi: I am new to this forum and looking to see if anyone has had the same problems I am having with two brand new 3 ton Carrier central air units. We had two 3 ton units installed in a 2800 sq ft older home complete with furnace assemblies with the variable speed fans. Within the first 3 weeks of operation we have had the dealer out 5 times due to them not being able to cool the house much below 79-80 degrees when set at 77-78 degrees. After 5 attempts(one was due to a blown fuse on the one unit)another was something to do with a valve not backseated properly..the units run practically 24x7, my July utility useage jumped 150% over previously highest month with two old 20 year old units.They now say both units have bad TXV's and they bypassed them with some sort of piston valve until they get replacement parts. Carrier said they had no replacement TXV's since the units are so new?Of course that makes no sense since I assume they are building them daily..but I find it strange that both brand new units have bad TXV's? Anyone else experience similar and what's the odds of both failing or is something else wrong and they are grasping at straws to solve the cooling issue?