What Causes A Central Air Conditioner Unit To Leak Water?

Many homeowners notice their AC unit leaking water and are instantly filled with dread. Truth be told, not being able to cool in the middle of the hot summer days or warm yourself when temps drop outside can cause headaches. This guide is created to help deal with a leaking air-conditioner unit yourself and know whether it’s time to call a professional. Of course, it is always better to act proactively than try to fix a problem. In this case, ensure you have your HVAC unit tuned up every fall and spring by a pro. Then, you can address efficiency enhancements and little repairs all by yourself, especially if you’re a savvy homeowner.

So what causes a central air conditioner unit to leak water? Read on to find out!

The first course of action

If you find an AC leak, make sure you handle the problem immediately before it creates any major issues. This is because leaking air conditioners can “eat” your walls and destroy your ceilings — and anything else around them. With the slightest sign of an AC leak (i.e., water under the indoor air handler), turn off the unit at the breaker box.

Reasons for AC leaks

Below are some of the most common causes of air conditioner leaks:

1. Problem with the drain pan

The evaporator coil is housed in the drain pan, which is right underneath your indoor air handler. Note that air conditioners usually have two drain pans. One is permanently fixed and located underneath the evaporator coils, and the other is removable and is found underneath the unit. If your drain pan is cracked or overflowed, the pipe that’s connected to the drip pan won’t be able to discharge the condensate outside, causing the AC unit to leak.

What to do

First, clean the overflow pan using a wet-dry vac. Then, inspect the edges, corners, and bottom of the pan with a flashlight. If you notice any cracks in the drain pan, you can use a water sealant for a temporary fix. The best course of action, however, is to replace the damaged pan. Although you can replace the auxiliary pans yourself, it will be challenging to change the primary pan as it is welded in place. In this case, you will probably need the services of a professional.

2. Frozen evaporator coils

A clogged air filter is the primary reason behind a leaking air conditioner. When it’s dirty, it hinders the passage of air, which in turn freezes up the evaporator coils. When the airflow is obstructed or restricted, ice forms (remember that the refrigerant that uses the evaporator coils to flow through requires proper airflow to absorb heat effectively). As a result, water drips from the formation of ice. It should be noted that frozen evaporator coils can also cause issues to your compressor as the refrigerant can no longer take in the heat from the room. Not having enough refrigerant, blocked registers, dirty coils, a broken blower motor, and blocked vents can also be blamed for frozen evaporator coils.

What to do

Turn the AC unit off pronto. Only turn back on when the issue is remedied. Replacing your air filter every one to three months will also help avoid frozen evaporator coils. You can set calendar reminders to keep track of when you need to check your air filter. Not covering your registers or air vents will also do. Now if the problem is not solved even after you clear all your vents and replace your air filter, it’s probably best to call for the services of an HVAC professional.

3. Clogged condensate drain line

With the right tools, this one will be a relatively easy task for a DIYer. Debris, algae, and fungi can block the condensate line. That’s why it’s critical to clear it every now and then to help eliminate any fungi or algae that develop in the line. 

What to do

First, locate the PVC pipe, which usually has a piece of pipe sticking up with a small cap on it. It will normally be near the drain pan of the air handler. Unscrew the cap and pour vinegar down the drain line. Around six ounces will do. If the line does not get unclogged with that method, you may need to either clear the line yourself with a wet-dry vac or call a professional.

If you prefer to go with the DIY idea, connect the wet-dry attachment to the condensate drain line and turn the vacuum on. If your wet-dry vac does not feature such an attachment, you will most likely be able to find one in the nearest home improvement store. You will know it’s time to use a pro’s repair services if the drain line is not connected properly, despite your hard efforts.

Conclusion

Running into a leaking air conditioner? Now you know where to start looking for a solution to your problem and how to fix it! If you don’t feel comfortable doing it yourself, you always have the option to call an HVAC specialist. Good luck!