OK, IF you had air flow from the OLD furnace set up thru all registers and now you do NOT, you have either MISSED connecting a duct hose or you have a FLOOR duct connection(rectangular) that you did not knock out that plug which is NOT round. This type the furnace when installed SITS on top the underfloor duct assbly. You will still have the 4 inch round knock outs as well. Doug
PS, when I replace a same model furnace, the FURNACE is the only thing I replace. NOT the outer casing, because the ductwork is already punched out and connected.
