Little residential hvac help please. Newer unit leaks water once a year.

67Dart273 said
EDIT. Just now saw ^^ Dicer's post. DO that. Add a tee and a short standpipe, perhaps 6"

I AM CONFUSED I used to do HVAC /R service and install and DO NOT KNOW what I am looking at

Is this a heat pump? Is this on the return side of the furnace? If it is on the RETURN side, the coil will be under a VACUUM, and the damn thing will attempt to suck water up and keep it up in the pan. (If this is NOT a heat pump and if it IS on the return side, IT DOES NOT BELONG THERE. The coil, that is.)

Anyhow you may be better off WITHOUT a trap at all. What may happen without a trap, is it may gurgle some when running, as it is trying to suck up water and air is blowing past. the water in the piping.

The unit is a heat pump, with the A/C fan unit outside, in my simple terms. The drain pipe is under the A/C bits that are inside the indoor unit, and there is a drain pan under that to catch the water that drips off the ac pieces in the basement portion of the unit. Idk if it's the condenser, compressor, etc, but the triangular thing made of coils in the pic (I have the panel off). The drain tube, made of pcv, is as the unit installer left it last. It connects to that drain pan. Not saying it's right, as the first time the plumbed it, they blocked the filter, and came out and redid it. I'm also noticing they didn't even plug a 2nd 3/4 port a little higher uphill, on the drain pan. The unit is a carrier, and it's honestly a pos. It works ok when it's working, but at only 5 years old, they have come out ay least 5 or 6 times for various faults. 2 of which are this water leakage issue at first start in the spring. Always no defects noted. And off they go with thier money in hand after mopping it up. It's also the loudest blower I have ever heard. We literally have to turn up the TV to hear it when it kicks in.
This time, the leakage came after a 18 hour power outage. Which again leads me to thinking it's some kind of trap, or siphon issue. The whole drain pcv tube does run downhill. No junk in the tube at all. I poured in extra water and it does drain out the tube...but it's still getting water on the floor somewhere.