Need assistance on trap selection

I recently received a code violation from a plumbing inspector in a rental home owned by our family, the nature of the violation was due to the furnace's A coil drain line being directly connected in a straight line to the house's drain stack. Originally the inspector stated that I needed to move the line to a floor drain across the room but when I told him that I'd prefer to not do that since the floor drain in this area frequently backs up and I'd prefer to keep the floor drain closed he stated that I could just install a trap in the existing line to prevent the sewer gas from entering the house. That sounded easy enough to me since I'm fairly good at sweating pipe so I figured I could just go and buy a 3/4" copper trap or something like that but after looking around I cannot find such a thing and I'm assuming the answer doesn't involve 4 elbows but I could be wrong!

Included below is a picture of the line in question... basically there is this small section of pvc that is connected to the copper which is about 3 feet long which connects to the drain stack. I haven't begun looking around for a pvc part yet because if it exists I'd prefer to do it in copper but at this point I'd just like to find the appropriate, readily available part to accomplish the job.

Thanks in an advance for any assistance you can provide!

It would look like this, but I also think he is worried about the direct connection to the soil stack.

You need a plumber to pipe this for you. My opinion.

trap

Most areas will not allow what you want to do for the simple reason that when the air conditioner is not operating, as in the winter or mild seasons, there is no condensation to maintain the trap seal and the blower will draw sewer gas from the drain system, just like it does now. The condensate HAS to enter the drain system through a trap which is maintained by other usage, such as the washer trap standpipe, or a sink tailpiece.

It would have to drain by an air gap, into a vented trap and as HJ points out, if the trap dries out it will stink the house up. Drain it outside. And if it's below grade, use a condensate pump.

hj & nhmaster, makes perfect sense. I just wonder why the inspector told me I could trap it then if that solution is only going to help me four months out of the year... if you're going to let me just do that you might as well just let me leave it the way it is considering it's been that way for at least 40 years now and there hasn't been any recent work to it at all!

The house does have a sewer smell and after all the remodeling we've been doing and the fact that we're ultimately going to sell it I'm at least considering running it to the floor drain or possibly another option? Can you roughly guesstimate the costs of material to go the condensate pump route? I'm within 5 feet from an exterior wall that I could run the pvc to.