You may not think about water leaking when you think about your air conditioner, so it might be surprising to find water seeping from your unit. Discover where this water comes from and why your air conditioner may be leaking.

Where Does Air Conditioning Water Come From?

Let’s start by examining how and why an air conditioner produces water in the first place. You might already know your air conditioner uses refrigerant as a crucial component in cooling your house. To cool your home, the pressure of the refrigerant reduces, causing it to get cold inside the evaporator coil. This process allows the refrigerant to absorb heat from the air circulating through the air conditioner. This heat is pushed outside, cool air is directed inside, and your home becomes a comfortable haven!

Have you ever noticed how a cold beverage sweats on a hot and humid day? When the temperature of a surface is lower than the dew point of the air, moisture in the air will condense on that surface. This causes a cold beverage to “sweat” and is the same principle that causes your air conditioner to produce water.

When working properly, that water, also called condensate, drips onto a pan placed under the evaporator coil. This pan has a drain pipe attached that allows the condensate to drain away from your unit. Depending on your home, this could be piped over to your sump well or through the wall of your house. In some cases, there may be a pump to help remove the condensate from the drip pan if the system isn’t positioned to allow gravity to do the work.

When this system is not working properly, you will start seeing issues with condensation leaking around your indoor unit. Here are some problems you may face lead to water leaking around your AC unit.

Clogged Condensate Drain

One of the most common issues causing AC water leaks is a clogged condensate drain. There are several things that might clog your drain. As condensate drips from the evaporator coil, it may pick up small bits of metal or rust from corrosion, or it might grab onto airborne contaminants like dust. The condensate drain is also a primary breeding ground for mold, mildew, and fungus because it is a moist and dark area.

To keep the condensate drain clear, it needs periodic cleaning. An HVAC technician will clean the drain as a part of a professional AC maintenance visit. You can also clean it yourself by pouring a cup of bleach, vinegar, hot water, or hydrogen peroxide down the drain at the access point. Do not mix bleach and vinegar because it will produce toxic chlorine gas.

Clogged Air Filter

A dirty or clogged air filter is the underlying culprit behind many problems with your air conditioner. All these problems occur because too little air is moving through the system. One such problem is a frozen evaporator coil. When insufficient air moves through the coil, it gets too cold. When this happens, condensation freezes on the evaporator coil. When that ice thaws, it releases more water than the condensate drain is designed to handle at one time and can cause the drip pan to overflow.

To prevent this, check your air filter every month and gently vacuum off the intake side. The common 1- and 2-inch filters usually need replacing about every 30 to 90 days, depending on whether they are flat or pleated and your home’s indoor air quality. Larger filters may last longer, so talk with your maintenance technician about the expected service life. Regardless of the size, when you see dirt visibly collecting on the intake surface of the filter, it is time for a replacement.

Leaking or Low Refrigerant

Your air conditioner relies on having enough refrigerant charge to regulate the pressure in the evaporator and condensing coils. When there is not enough refrigerant in the system or if there is a leak, the system may freeze because the refrigerant pressure is too low. The refrigerant system is sealed, so unless there is a leak, it should maintain the proper charge continuously.

Checking your refrigerant charge requires specialized equipment most people do not own, but is a common part of an HVAC professional’s toolkit. A technician will check the charge in your system when they come out for your annual AC maintenance visit. If it is low, they will discuss the options for tracing the leak and recharging the system.

Mechanical Issues

There are multiple mechanical issues that will also lead to a frozen evaporator coil and water leaking from your unit. In the indoor unit, your circulating fan may not be spinning as quickly, reducing the amount of air moving through the system. Like a clogged air filter, this can lead to a frozen evaporator coil inside.

A malfunctioning thermostat can also cause the coil to freeze, leading to the dreaded water leak. A thermostat will usually last 10 to 15 years, after which it may stop sensing the temperature accurately. When this happens, it can make the system run longer cycles or cause the compressor to work too hard, wearing the system excessively. As this occurs, it may not control the refrigerant pressure properly, allowing the refrigerant in the evaporator coil to get too cold and cause the coil to freeze.

If your system has a condensate drain pump, this may also leak. You could have corrosion where the pipe attaches to the pump or a mechanical problem within the pump itself.

Incorrect Installation

Incorrect installation may include a unit that is not leveled properly. This changes where the condensate falls, potentially allowing it to drip on the floor rather than in the drip pan. If this is an issue, you will notice when you start using a newly installed AC unit. Contact your installer to have them come out and correct the issue.

Plumbing Issues

It may be that your air conditioner isn’t the true source of the water leak you see. Depending on the location of your system, it could be piping above the air conditioner that is leaking. In some cases, it could be the condensate drain piping or your sump piping that has sprung a leak. Take the time to investigate if there is possibly a different problem that needs attention. A leak, especially above the air conditioner or air handler, can wreak havoc on your system, so contact the appropriate professional to resolve it quickly.

Join everyone in De Pere and the surrounding communities who has trusted the award-winning team at Healthy Home Heating & Cooling LLC to keep their homes comfortable. Our technicians provide heating and air conditioning maintenance, repair, and installation services. We are also experts in heat pumps and ductless systems. In addition, we offer indoor air quality and duct cleaning services. Call to schedule your AC maintenance or repair appointment with one of our high-experienced technicians at Healthy Home Heating & Cooling LLC today.

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