Blower BANGS when furnace stops
As far as the 'banging', could it be the ducts flexing back in place? To check this, the next time the unit comes on, go down there and put your hand on the plenum side of the unit (the output side.) WHen the unit shuts off, you'll know if it's the duct or not. I did have this problem and fixed it by bracing the 'soft spot'.
My best to ya and hope this helps.
Jay J -Moderator
PS: The new blower may have a greater 'push' than the old one. It's just a hunch I have.
You are exactly correct, sorry for the latent heat terminology, I should have used residual.
However, since an increase in fan speed results in a higher delta temp of the combustion gas through the heat exchanger, (the flue gas exits the heat exchanger at a lower temp) the net result is the furnace becomes more efficient.