I am in the process of having my existing HVAC system replaced. Everything except the existing duct will be changed out. My existing condensor had a burn out therefore I requested that the original lineset be changed. The condensor being installed is a 4 ton 14 Seer Goodman CLT48 and the coil is a Goodman CAPF061C2A and the furnace is a two stage Goodman GMV90905CXA.
My question is regarding the lineset size. The installer is planning on replacing the lineset with another 7/8" suction line. I was reading in the installation manual that Goodman specs a 1 1/8" suction line for installations with lineset lengths greater than 25'. My lineset length will be just under 35'. From the coil it will run about 2' up and out of the utility closet and about 22' through the attic and then drop from the eave about 8' and then about 2' over to the condensor. The installer indicated that the 1 1/8" is overkill for this installation and that 7/8" should be used. What are your professional thoughts on this? Also, is 3/8" insulation on the suction line adequate? I am concerned because this line will be running 22' through a hot Texas attic.