HVAC condensate drain

[Blackhawk]

I understand that I can't connect my HVAC condensate drain directly to the sanitary sewer if I am only using the condensate line trap. Is it OK to attach the condensate line trap to the fixture side of a laundry sink trap? This would keep the condensate line trap from drying up.

[HayZee518]

the only reason for having a trap in the condensate drain line is to eliminate sewer gases from infiltrating into the a/c drain pan. if you drain the line into a laundry sink, the sink already has a trap so I'd eliminate the trap on the a/c altogether.

[Blackhawk]

Well, after looking at this further. I don't think it would be good to attach my condensate line to the fixture side of the laundry trap in my situation. My HVAC unit is in the same room with my laundry sink. The condensate exit from the HVAC would be only a couple of inches higher than the bottom of the sink. I think that you would want the condensate exit to be at least as high as the top of the sink. If I ever dumped a huge bucket of water in the laundry sink, I could see the water backing up into the condensate line before it could drain out of the sink trap. I think that I will just run the condensate line to a condensate pump under my sink and then let it pump the condensate up and over the side of the sink. If anyone has any simpler ideas that would save me the cost of a pump, I am all ears.

Hayzee - I agree that if I could have attached my condensate line to the fixture side of the sink trap, I could eliminate the condensate line trap. But, I have read that the condensate line trap is recommended if you have it draining to the open, as through a wall to the outside or to a sump pump. What I read explained that the trap helps to prevent cold air from leaking out and also prevents insects from getting into the HVAC unit.

[HayZee518]

ok, now I understand the reason for it. but thinking about the size of it 3/4 or 1 inch, is it that much air flow leakage through it?

[Redwood]

Many units require a trap to keep the airflow in the unit sealed as well.

Your planning sounds on target Proceed!

[LazyPup]

AC condensate drains are required to be discharged outside the structure or into an approved "Indirect Waste Receptor". They may not be connected directly to the house DWV system.

To create an Indirect waste receptor the lowest portion of the condensate drain line must remain 2x the pipe diameter or 2", whichever is greater, above the flood level rim of the receptor.

The intent is to prevent bacteria from the DWV system from getting into the condensate line and eventually into the AC evaporator where it could become airborne throughout the structure.