Why doesn’t the air conditioner’s drip pan drain properly

air-conditioningcentral-airhvac

My AC Unit in my attic is roughly 10 years old, still heats/cools exactly as it should, but I noticed yesterday that the drip pan is overflowing.

What do I need to do to get the drip pan to drain? And what is causing the drip pan to fill?

Best Answer

I had a problem like this many years ago. I did some experimenting:

  • I found if I disconnected the condensate drain pipe, the water would flow out of the A/C without restriction.
  • I could pour water into the disconnected pipe and it would flow easily.
  • My condensate drain pipe ran to the drain pipe of a nearby bathroom sink, which was draining just fine.

I concluded there was a pressure problem and the condensate drain pipe would work correctly if I added a vent.

Here is a picture of one person's solution. It doesn't look too elegant, but it illustrates the method.

My drain pipe ran from the condenser to an elbow, and then vertically downward, IIRC. I just replaced the elbow with a tee and added a short length of pipe at the top of the tee, leaving it open at the top end.

Problem solved, in my case.

Now, it had been working fine before all of this happened. But the problem showed up just like you described it. I don't know why or how it was working before I did this, but I never had trouble again.

enter image description here

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