AC Unit Leaking Water: Common Causes & Solutions
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What to Do If Your AC Is Leaking

Diagnosing AC leak problems and determining potential solutions
Read Time: 6Dec 10, 2020

A leaking air conditioner almost always indicates a mechanical problem that’s normally associated with a lack of maintenance. Air conditioners produce condensation as a byproduct of cooling, but when dirt or debris interfere with its production and drainage then leaking or flooding may occur inside and outside of the air handler.

Potential Problems That Could Cause Your AC to Leak

There is no one single reason for your AC leaking water. When you begin to notice a buildup of standing water, you’ll have to do a bit of sleuthing to uncover the exact reason. In some cases, the true cause of the AC leaking may not be something you can diagnose on your own.

If that’s the case, you’ll need to bring in an HVAC technician to figure out what’s causing the leak. But it’s worth a shot to try and figure it out on your own. There are some causes for leaking you can easily fix on your own.

Note: Before you begin inspecting your AC to determine a potential source to the leak, always do the following:

  • 1. Shut the unit off. You don’t want the system to continue leaking water.
  • 2. Clean up any standing water to prevent water damage to the surrounding area.

Taking the proper precautions can help to diminish any further damage to your unit or the area surrounding your unit.

Your Air Filter is Dirty

Man changing air filter

A dirty air filter reduces the airflow over the coil and slows the heat transfer from your home’s air to the refrigerant. You should regularly replace your air filter. A good rule of thumb is to change it every sixty to ninety days. You should replace it more often if you have a pet as more hair and dirt will collect over a shorter span of time.

You can try replacing your air filter to see if it helps to correct the leaking. But more than likely, once your AC is leaking, you’re past the point of a simple air filter change fixing the problem. Dirty air filters can cause problems with the AC evaporator coil which will then need to be fixed separate of the air filter.

Solution: Replace your air filter, and form a habit of replacing it every sixty to ninety days moving forward.

Refrigerant Levels in Your Unit Are Low

Low refrigerant levels will cause the unit to become too cold. This will result in the evaporator coil becoming too cold. The evaporator coil will then freeze over. The idea here is similar to how a dirty air filter can cause leaking to occur in your AC unit. Once the evaporator coil freezes it will thaw and drip water into the drain pan. This, over a period of time, will overwhelm the drain pan and can result in leaking.

While this problem turns into a problem with the evaporator coil, it originates with the refrigerant levels. You’ll want to monitor the levels of refrigerant in the system to ensure it never becomes too low and turns into a larger problem.

You can tell the AC leaking is caused by low refrigerant levels because your AC unit will stop cooling your home. If this is the case, you’ll need the help of an HVAC professional to have the refrigerant levels restored.

Solution: Have your refrigerant checked by an HVAC professional.

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Clogging or Cracking In Your AC’s Drain Pipe and Pan

HVAC unit outside of home

Overflowing water caused by a clog or crack in your drain pan or pipe can easily be fixed by identifying the crack, replacing the cracked AC part and removing any clogs.

Over time, the drain pan and drainpipe for the AC can clog from dirt, dust, mold, and even yard debris. Check the pan at the base of the air handler and remove any debris. Outdoors, remove any blockage. You may need an HVAC technician to clear a completely clogged drainpipe. A professional will have access to chemicals and snakes to clear the line.

When searching for cracks or clogging in the AC drain pan and pipe, you’ll first need to remove any water. You can do this using a wet-dry vac to accomplish this. Then take a close look for any cracks. You can use a flashlight if you need to more closely check the pan for cracks.

If the leak is due to a crack in your drain pan you can patch the problem with a water sealant. You won’t want to use the water sealant as your final solution, however. Order a replacement pan to keep the leaking from coming back.

Solution: Clear away any debris and replace the drain pan if cracked.

The Evaporator Coil Has Become Frozen

You’ll probably know when your evaporator coil has frozen before you notice the leaking air conditioner. When the coil freezes over, cooling stops even though the system may continue to run. Reduced airflow is the primary cause of a frozen coil, generally caused by excessive dirt.
Over time, dust can collect on the coil, especially if your system hasn’t been professionally maintained. Running it without an air filter or with an overly dirty one will deposit dust over the coil, or the coil may be covered with mold. Because the evaporator coil is not having constant flow over it, it will become too cold and freeze. As it melts and refreezes and melts again, the excess water can overwhelm your system and lead to leaking.

An HVAC technician can clean the coil and routine air filter changes will prevent dust from building on the evaporator coil. If mold is present, have your HVAC technician install UV (ultraviolet) lights that shine on the coil to prevent biological growths.

Low refrigerant can also cause a frozen evaporator coil, a condition only a licensed HVAC technician can diagnose and solve. If none of the other mechanical problems exist with your system, call your contractor for a system check.

Solution: Replace your air filter and have an HVAC professional check your refrigerant levels and clean off your evaporator coil.

Is a Small Amount of Water Leakage Normal?

Water drop falling in puddle
A small amount of water from condensation from your AC unit is completely normal. It’s the amount of water leakage you’ll want to keep an eye on if you begin to suspect your unit may be broken. Your AC should not be leaking water from condensation when it’s not running. You’ll also want to check that any puddles that form beneath your unit dry within the day. If it doesn’t, it’s time to begin inspecting the unit for potential breaks.

Is Water Leaking from an AC Dangerous?

Water leaking from your AC unit isn’t necessarily dangerous to the occupants of your home. However, it can be damaging to your home if not quickly cleaned and repaired. Water damage can set in within 24 to 48 hours and cause a bigger headache than necessary.

While water leaking is the more common type of leaking in AC units, there is a small possibility of refrigerant leaking being the cause of your AC’s leak. If you suspect this is the case, you’ll need to contact your local HVAC professional immediately. Refrigerant leaks can be incredibly dangerous to occupants of your home when the refrigerant turns to gas.

Is It Okay to Use My AC While It’s Leaking?

It is better to keep your AC unit off while working to get the leak solved. By keeping your unit on you could cause further or increased leakage. This can not only damage your unit further but it could also cause damage to the surrounding area. Cut back on an extra headache by doing whatever you can to avoid water damage to your home.

What is the Best Way to Fix a Leaking AC Unit Quickly?

HVAC technician checking refirgerant levels

If there is no simple, DIY solution to your AC leak it’s time to call in the experts. Having your local HVAC technician take a look at your unit can help you quickly and easily find a solution. Your technician will be able to quickly find and repair the cause of your AC’s leak.

Prevention is the best way to avoid a leaking air conditioner. Having an inspection once to twice a year will help detect and treat problems. Having a standard inspection done in the spring and fall can prepare your unit for the seasons when it has to work the hardest (and is susceptible to needing repairs).

Whether you’re looking for a simple inspection or are hoping to get your unit fixed, contact Rinaldi’s Energy Solutions for top-notch HVAC services for Orlando-area homeowners.

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