How to Stop AC Water Leak

By Vernon Trollinger, July 26, 2017, Energy Efficiency, Green, Home Improvement, Save Money

Welcome to the How Do I Do This? series from Bounce Energy. Each month, we’ll dive into what it what you need to know to shop for, install, or repair those things in your home to keep your life affordable and convenient. Plus, you’ll (hopefully) learn some useful tips for other projects along the way.

How To Stop AC Water Leak

The last thing you want to see when you enter your home after a long day at work is a steady stream of water falling from a badly stained ceiling into the middle of your living room. Not only is it making a mess, but you know for certain that apart from the Christmas decorations and two boxes of old clothes, there’s nothing else up there except for the air conditioning system.

The Cause

Where’s the water coming from?

Water condenses on the air conditioner’s cooling coils, dribbles down into a collection pan, and then drains away down a pipe. You don’t know the water’s even there because you never see it.

Why am I seeing it, now?

It’s likely the drain on the AC units condensate drip pan, or the drain line, has gotten clogged. It’s a common occurrence that can happen without some periodic maintenance.

What causes the clog?

A medley of dust, mildew, and bacterial slime.

Is fixing this going to cost me a lot?

You could call a professional to come. But with all this summer heat, you might wait a day or two until somebody can come to your house. In the meantime, you’d either have to turn off your AC to stop the water leaking or start using buckets to catch the falling water.

However, this problem is easy to fix and requires no special skills. All you’ll need is a small bottle brush, a wet dry vacuum cleaner, a spray bottle containing a cup of bleach or vinegar, and some paper towels.

The Cure

For safety, turn off your AC system before you begin. You’ll want to wait a little while to let the leaking water drain.

  1. Look for the drain tube from the condensate collection pan outlet. It’s usually a PVC pipe located below the coolant line connections.
  2. Disconnect the drain tube from the collection pan outlet and use the wet-dry vac to suck up any remaining water coming out of the drain.
  3. Carefully insert a small bottle brush to ream it out. You want to clear out any and as much gunk as you can. After that, spray some bleach or vinegar into the outlet hole.
  4. Next, use wet-dry vac to suck out any debris or other gunk that might have accumulated in the pipe. Afterwards, pour a little bleach or vinegar down the drain pipe to kill any mold or mildew.
  5. Reattach the drain tube to the collection pan outlet. You should be good to go.

I can’t remove the plastic drain piping from the pan outlet. It’s glued in place!

You’ll need to saw off some of the PVC pipe and then make a new detachable connection.

  1. Look for a straight section one or two inches downstream from where the PVC pipe connects to the thread pan outlet connection and cut the pipe.
  2. Using a pair of gas pliers, unscrew the PVC pipe from the threaded pan connection.
  3. Clean out the pan and drain piping as described above.
  4. Reattach the threaded PVC connections. Use the PVC coupling to join the pipe where you cut it. Don’t glue this connection since you can disconnect it for periodic maintenance.

TIP—Because periodically cleaning the condensate drain and pipe is cheaper than cleaning up a costly leak, it pays to make the job easier by installing a simple clean-out using a T-joint and a snug fitting pipe cap.

Caution— Do not install the T-joint downstream from the condensate trap. Like water in a sink trap, condensate traps fill with water. This protects your AC system’s efficiency by preventing cooled air from blowing away down the drain pipe.

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A native of Wyomissing Hills, PA, Vernon Trollinger studied writing and film at the University of Iowa, later earning his MA in writing there as well. Following a decade of digging in CRM archaeology, he now writes about green energy technology, home energy efficiency, DIY projects, the natural gas industry, and the electrical grid.

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