I have this sticky black liquid slowly leaking from my gas furnace / ac unit. I called an HVAC repairman and he wasn’t sure what it was. He said he thinks it’s an old drip pan made of tar (not sure that makes sense.) He said he cleaned it up a bit and to call if it started leaking again.
It’s one week later and it’s started again. I’m not sure what it is or if it’s a fire risk. He said the AC unit sits above the furnace and that it’s coming from the AC. It’s winter here so the AC unit is never running, just the furnace below it. I included a picture, does anyone have any idea what this is and what’s causing it?