I did a changeout today and removed a 150k btu lennox furnace. Originally, I was only going to change the coil, line set, and condensor but the discharge opening was 30x20 and nobody makes a coil with those dimensions. So it all had to go. Furnace had a 5 ton drive and the condensor was a 5 ton luxaire. The coil was a dual circuit with two suction lines going to a heder and then into the condensor. The discharge was 1/2 inch. I replaced it with a 4 ton system, 100k 90% Gibson. I will be there again tomorrow. Should be easier with out all the lifting. That furnace was a beast to get up the stairs. Just my blaber for the day.