What's this device (circled in blue) that's attached to my furnace? It recently got replaced and I forgot what the HVAC technician called it, or what its function is.
I do rember that they said to put some vinegar in the U-bend (circled in red) once or twice a year. I forgot to ask why this is necessary, but I'd guess that it tends to collect moisture, and the vinegar will prevent mold?
Condensate pump. It fills up with water and then pumps it up that pipe and outside somewhere.