I'm a newbie heat pump owner and will try my best to describe my concern.
I have a split system Luxaire 92% efficient propane fired updraft furnace and outdoor 12 SEER York heat pump. The setup is such that the furnace is stacked on top of the indoor coil. The order is cold air return to indoor coil to furnace to plenum to trunk. I think it was setup out of laziness by the previous owner when he ripped out the older electric furnace and just stacked propane furnace instead of rearranging everything.
I've had 4 different techs work on this system for periodic maintenance and other things. All have said the coil is in the wrong place, and should be above the furnace. That is it should go cold are return to furnace to indoor coil to plenum to trunk.
The youngest tech, a pimple-popping fresh out school cocky teen, was appalled at this setup and gave other wrong information. I give his opinion the least weight. One older gray-haired tech who really seems to know his stuff from what I can tell, measured delta temperatures (inside the plenum to outside) in heat or cool mode at the plenum (just above the furnace) and said they were "textbook" (i.e. prefect).
Still no one has explained why this setup is wrong. In fact, the older gray-haired tech said this setup might have the advantage of being able to run the HP and furnace in tandem, instead of exclusively.
Can anyone tell me if this is wrong, and if so why? And how bad is it?