This is my 1st installation after getting my EPA certificate. I'm trying to connect a Frigidaire 4 ton condenser unit, 3/8" liquid line and 7/8" suction line, to a horizontal furnace that has a label rated for 4 ton evap. However, the pre-existed plumbing lines through the walls are 3/8" liquid line and 3/4" suction line (instead of 7/8"). Will this unit function normally if I use a reducer 7/8" to 3/4" on the suction line? My other thought was to return the 4 ton for a 3 ton condenser unit which has the 3/4" suction line. Also, I have not purchased the evap coils yet.