Keeping Your Home Cool during the Sweltering, Summer Months

Uh Oh... The Air Conditioner Is Leaking!

by Anthony Graves

When you descend the stairs into your basement and see water puddled on the floor around your air conditioner, it's normal to feel a bit panicked. What's wrong with your air conditioner? Has something major broken, and how much is it going to cost? Take a deep breath, and stay calm. There are several possible causes of leaking air conditioners, and most of them are fairly innocuous and easy to fix. You might not even have to call your HVAC technician at all. Here's a look at the most likely causes and how to fix them.

1. A clogged drain line.

Your air conditioner does generate moisture as the evaporator coil pulls heat out of the air. Normally, this moisture drips down into a drain pan and is then pumped through a condensate drain line either to a drain or a sink. If the condensate drain line becomes clogged (which can happen quite easily in a dirty basement or if you don't change your air filter often enough), the water won't leave the drain pan. Instead, it will flow over its edges and onto the floor.

You can check for a clog in the drain line yourself. The line is usually made from clear, flexible rubber. So, just look through the rubber to see if you can spot any debris. If you do see a clog, hold a wet/dry shop vac nozzle against the end of the line. This should suck out the debris, allowing water to flow through the line again. In the worst case scenario, the clog won't come free. If this happens, turn your AC off temporarily. Then, you can simply detach the drain line from the pump and take it with you to the hardware store to buy another identical section. Reattach the new drain line, and turn your AC back on again.

2. A dirty filter and coil.

You're meant to change your AC filter about once a month during cooling season. If you let the filter get too dirty, dust starts building up on the evaporator coil. The dust impedes the coil's ability to absorb heat from the air, so the coil gets too cold. Condensation starts freezing on the coil, and then when the system switches off, this condensation melts. If there is too much condensation at once, it tends to overflow the drain pain and end up on the floor.

If it has been a while since you've changed your filter, swap it out for a new one. Also, turn your system off and clean your evaporator coil to nip the freezing-melting-dripping cycle in the bud. Coil cleaners are sold at most home improvement stores. You simply spray them onto the coils and let them work their magic. They'll drip off, along with dust and debris, as they work. Then, you just clean the cleaner up off the basement floor. Follow the directions on the label of the particular coil cleaner you buy for best results.

3. A broken condensate pump.

If your drain line is not clogged and you've been keeping up with filter changes, then your condensate pump may simply not be working properly. Sometimes the motors burn out prematurely. Watch the pump to see whether or not it switches on at all. It may switch on but make a struggling, grinding noise rather than actually pumping water out of the drip pan.

Replacing the condensate pump is a job for your HVAC technician, albeit not a very large one. The pump is usually a separate unit from the AC unit, so your technician should be able to replace just the pump without making any major changes to your system. In the meantime, you can place a big bucket under your drain pan to collect any water that drips down. This will allow you to keep using your AC until your HVAC technician arrives without flooding the floor.