Why is A/C evaporator drain dripping?

Question

I noticed that my secondary drain line from my home A/C evaporator coil was dripping, so I went to the attic to check the primary drain. I disconnected the primary drain line and it was wet inside, but water was not backed up in the line and I could easily blow through it.

All seems to be clear, however, the secondary drain outlet is still dripping into the pan. Why is it doing this?

Answer 1

As you know, the one thing that makes the drain line "secondary" is that it is positioned above the primary drain, and won't get any water unless the primary is blocked in some manner.

The only thing that I can think of is that the horizontal installation of the air handler has somehow got the secondary line in a relative position to catch water without a drain back-up. As unlikely as this seems, I am baffled otherwise; unless the dripping is merely condensation, as your other answerer has suggested. In that event, insulating the cool surfaces with cork tape or Rubatex should solve the problem.

Answer 2

why would the secondary or primary drip INTO the pan. the pan collects condensation which drains into the primary...if this becomes clogged then the water will rise to the secondary and drain the pan. if you mean that you find the sec drain doing the the work and you are positive the primary is clear then the pan is not level and as has been already answered the water is being directed to the higher of the two drains. if the condensate is covering the the inlet to to the primary then it is clogged and needs to cleared.

Answer 3

It is part of the cooling process. Like water drops on the outside of a cold glass of water. Not to worry.