condensate drain to sewer line??

I’m sure this has been asked before, I did a search of the MB, but couldn’t find a definitive answer. A new (6 month old) high efficiency nat. gas hot air furnace has it’s condensate pump on the floor. The drain tubing ran up to a floor joist, across the basement, and is connected directly into the septic main. There is no trap or air gap, and the horizontal portion of the tube is full of water- I observed an air bubble travel up FROM the septic line to the horizontal section of the clear vinyl tubing. Seems to me that this has to be wrong! Am I right?

Yes. It needs an air gap/indirect connection where it can’t syphon back.

Thanks, Larry. I was pretty sure that I was correct, but wanted to be sure.

Won’t an air gap allow sewer gasses to enter the living space? I think it needed a trap. A furnace won’t siphon but you could wind up with sewer gas entering the supply air stream via the condensate tube at times when it’s not full of condensate.

And that needs to be an air gap, not an air break… which means that most of the indirect receptors for HVAC systems I see are wrong.

DWV - Air Gap vs Air Break - Diagram.gif

Yes Kenton a trap is needed and a funace condensate line can siphon back to overflowing the condensate pump and all over the floor. I’ve seen it from a laundry tub.