A draining experience with our central air conditioner

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

We had moved into our new home in late June of 2013. One of the ‘joys’ of home ownership is finding that something was not built so that it could be maintained properly.

 

Sometime in August I heard water dripping behind the wall of the master bedroom. One possible source was condensate from the part of the air conditioner located up in the attic. Access to the attic is via a hatch on the ceiling to the walk-in closet off of the master bedroom. I climbed up there and found that the secondary drain pan (shown above) was overflowing. After I bailed the water out, I could see the opening for a plastic pipe running out the back side. It exited the back wall of the house above a second story window. The builder had warned us that if we ever saw water coming out, then there was something very wrong. I stuck a four-foot wooden dowel rod into the pipe to clear it.

 

Then earlier this August the secondary drain pan overflowed again. Of course, it happened at 10:30 PM on a Saturday night. I felt water drops from the smoke detector on the ceiling of the second-floor hall. Then I stepped into a puddle on the carpet. I got a ladder, went up to the attic, and bailed the water out.

 

Later I looked up some YouTube videos about air conditioners and their condensate drain systems. The air handler box for an air conditioner contains an A-shaped coil which cools the air. If air is cooled to the dew point, then condensation occurs. The bottom of the air handler has a primary drain pan for collecting that water. A plastic primary drain pipe runs from the wall of the pan to a trap, and then downwards to eventually leave the wall near the air conditioner condenser unit on the ground outside.

 

Another overflow pipe leads out from the primary drain pan and into the secondary drain pan. It also has an emergency plastic drain pipe running from the wall of the pan out to the wall of the house, above a window. Sometimes the secondary drain pan has a float switch to turn off the air conditioner (Ours did not).

 

If debris collects in the trap on the primary drain pipe, then it can get clogged. The videos advised that you should take off the cleanout cap, and push a plastic cable tie or snake into the pipe to break up the clog. But I didn’t have a cleanout cap on my drain pipe (yet), just an elbow heading downward.

 

Then I tried removing the access panel on the air handler to get at the pipe from the inside, but still could not get to the clog. Videos also said you could connect a wet shop vacuum to the outside end of the drain pipe to suck the debris from the pipe. I tried that without effect. At this point I gave up on my do-it-yourself approach, and called Advanced Heating and Cooling.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Their technician redid the drain piping to add a cleanout cap (as shown above in a close-up). He blew out the line with nitrogen gas, and then flushed a couple gallons of water down it to finish cleaning away any debris. Now the primary drain is working correctly, and I know how to maintain it.

 

Apparently back in 2013 the primary drain was not completely clogged. It took eight years for that to happen. So back then I had missed going after the root cause of the problem.