Ok, we have a Goodman unit we installed. The unit is a 14 SEER 410a unit. Everything checked out fine. It does have a Variable Speed Airhandler. The problem is the unit will freeze up. We replaced 2 defrost boards in it and then swapped out unit. Still have same problem. It will test into defrost. Yesterday we had a "goodman rep" out and he said everything looked good and had us changeout the T stat wire. I asked the tech why they just didnt ohm out to see if had short. The rep said could be intermitten problem, but all AHU setting were correct as well as charge. Any thoughts.