Wonder Why Your Air Conditioner Leaks Water? Here's What You'll Want To Know

Posted on

Of all the things that could happen to your air conditioner, a water leak is perhaps the most surprising. Finding a puddle of water near your A/C unit can be puzzling and sometimes frustrating, especially if you don't know where it's coming from. Fortunately, the following explains how this happens and what you can do to stop it in its tracks.

How Water Forms in Your A/C System

Located within the air handler plenum, the evaporator coil lies at the heart of your A/C system. This radiator-like device is what helps your unit pull latent heat from the air that passes near and through it. But the act of removing latent heat also removes moisture – as air temperatures decrease, so does the air's ability to hold moisture in vapor form. As the evaporator coil lowers temperatures by pulling in latent heat, the moisture in the air condenses into liquid form and falls into the drip tray below.

How Leaks Occur

Ideally, the condensate that falls into the drip tray ends up being funneled through a nearby drain, where the condensate is then flushed into a drainage point within or outside of your home. However, there are a couple of ways that simple process can go awry:

  • Blockages – Dirt, dust and debris can collect inside of the condensate drain, creating blockages that allow the condensate to accumulate and eventually overflow out of the drip tray. Mold and algae can also grow within the damp confines of the plenum. When it reaches the condensate drain, it can also cause blockages that lead to leaks.
  • Drainage line leaks – A loose, cracked or completely broken drainage line can also allow water to leak through. Most leaks are caused by accidental damage of the PVC line, insufficient or failed adhesive between PVC joints or an aging PVC line that needs replacement.
  • Drip tray leaks – Plastic drip trays can develop cracks and leak water, while metal trays experience rust and/or corrosion. Either way, the tray itself can become a problem.

Dealing with Leaks

Before you get started, you'll want to shut off your A/C system at the circuit breaker to minimize the risk of shock. Use a wet-dry shop vacuum or a mop and bucket to remove any standing water pooled around your A/C unit.

Now you can carefully inspect your A/C system for leaks. Start by taking a look at the drip tray. Get rid of any remaining water in the drip tray and then check the pan and drain for signs of debris blockage and/or mold growth. Most drain blockages can be removed with a little suction from the shop vacuum, although stubborn clogs may have to be dislodged with a small plumber's snake.

Afterwards, give the drip tray a thorough cleaning with some mild detergent and warm water. This also gives you an opportunity to carefully check the tray for any cracks or signs of corrosion. In most cases, spotting either usually means the entire tray has to be replaced. Otherwise, finish up by pouring a half-cup of bleach or vinegar down the drip tray drain. This will help curtail mold and algae growth.

Next, take a look at the PVC drain pipe leading from the drip tray to the drain outlet. Carefully inspect the piping for cracks and gaps. Depending on the size of the crack, most can be patched up with plastic or PVC pipe sealant. If a portion of the pipe has come undone due to weak or failed adhesive, use a putty knife and coarse sandpaper to scrape away as much of the old glue as you can and reapply fresh glue to the fitting.

With these tips, you can solve just about any water leak you happen to encounter when using your A/C system. For more information on resolving A/C system issues, check out a company like Always Ready Repair.