This was from today’s Inspect don’t even want to start the write up, its going to be nasty
No safety pan under A-coil
Return air duct separated allowing attic air into return
Supply air duct separated and crushed at coupling
The return air blower compartment not sealing allowing return from attic
Burners were rolling out
The supply plenum had been added on to accommodate an added on area of the home and was robbing most of the air for the original section of the home.
This was a 1979 Rheem and the Delta T was 20 degrees hard to believe