At a loss today. 1943 built home with furnace that is only a couple years old. High effeciency oil burner. Then I noticed that the barometric damper had been sealed with clear silicone. Has anybody seen this done before? And perhaps a reason why?
Also, in opening the cabinet, there was a lot of powdery substance in the bottom of the tray. Not sure what it is except maybe an absorbant for spilled oil. The furnace tech was leaving just as I arrived. Any clues?