What should the temp rise be on a Ng Lennox Dimension 93% 2 stage furnace from return to just at the AC coil with new filter, clean squirrel cage and all ducts open and on low fire of a 2 stage. Mine is
67 in 137 out a 70f rise. Isn`t that to high indicating it is oversized for the ductwork. I thought 50- 60 was inline. It is a bit oversized and I am looking at less Btus on a replacement. The Lennox supposedly was sized correctly as return and supplies were added.