re: HVAC Help Needed

most assuredly the coil. tell him to look harder. all 3 of mine (Trane) failed within 10 yrs. None under warranty. (2) were replaced. I bought the parts and paid someone to install. Can't remember the labor cost.It didn't strike me as unreasonable, though. last one was 2.5 ton, rarely used, upstairs unit. so just replaced the whole AHU.