It doesn t seem correct.
Condensate into attic sewer vent.
I would imagine sewer gases could vent into the air handler.
In older homes condensate lines located in the attic where the evaporator coil is busy removing humidity and cooling the air with refrigerant charged lines are not tied to a home s plumbing system.
There is a trap but it dries out during the winter.
According to some experts and plumbing codes this is an improper plumbing connection and for some lines there also is no condensate trap in this plumbing arrangement risking possible bacteria or even dangerous sewer gases entering the building air handling system.
And to clarify that an indirect waste pipe is something upstream of a trap rather than downstream and this includes the main venting stack as well.
This backup condensate system requirement refers for example to an indoor air handler installed in an attic or in living space where leakage into the attic ceiling or onto a floor system could cause damage to the structure.
Normal condensation in a plumbing vent pipe should stay within the pipe.
The pipe is also picking up heat from the central heating.
This is causing the condensation.
Below is a second example of improperly connected air conditioner condensate drain lines to a plumbing vent.
The vent opening should always rise above the trip level of the condensate overflow switch when it is in the primary drain line or pan or above the secondary aux overflow port on the primary drain pan.
The air in the attic is a much lower temperature than the hot water running into the soil pipe.
I was adding insulation to my attic recently and noticed that the air handler condensate line was running into my stack vent.
The other possibility is that a large amount of air is leaking around the holes in the dw and depending on the house.
This helps ensure that if a backup occurs that the water properly trips the switch instead of overflowing out of the vent.
Should this be fixed or should it be left alone.
The trap in the bathroom sink also prevents the sewer gasses from coming into your home and into your air conditioning system.