Noticing water leaking out of your furnace or pooling up on the floor around it when your AC is running can be quite scary and may lead you to think the worst. This is a common problem and, luckily, one that is usually easy to resolve. Although it may look like the water is coming from your furnace, the fact is that this issue is still related to your air conditioning system. Before we discuss the issues that can cause this type of leak, it’s first necessary to take a quick overview of the different parts of your air conditioning system to help you understand where the water is coming from.

Understanding the Parts of an AC System

Central air conditioners work by using a cold refrigerant to remove heat from the building and thus lower its temperature. Outside the building is the AC compressor, which both supplies cold refrigerant to the system and disperses the heat that the system absorbs from inside.

A set of copper refrigerant lines run from the AC compressor to the evaporator coil inside the building, which is located within the air handler compartment. For buildings that have both a furnace and an air conditioner, the air handler is the large metal chamber that typically sits on top of or possibly next to the furnace.

When the AC is running, the HVAC blower is constantly drawing hot air into the air handler. The temperature difference between the cold refrigerant flowing through the evaporator coil and the hot air being forced over the coil causes moisture in the air to condense into the water on the coil. This water then drips off the coil into a drain pan that sits directly below it. From there, the water then travels through a series of condensate drain lines that empty out either into a floor drain or directly outside.

Any issues with this condensate drain system can lead to water beginning to leak out of the air handler. Since the air handler typically sits directly on top of the furnace, this can make it look like it is the furnace itself leaking when really the issue is related to the AC’s condensate drain system. Although water leaking from your AC isn’t always a major issue, it is still something you should take care of as soon as possible since it could damage your furnace if the water starts to drip inside of it.

Condensate Drain System Is Clogged

The most common reason that water will leak out of the air handler is due to a clog somewhere in one of the condensate drain lines. If there is a clog in the system, the water that condenses on the evaporator coil will eventually back up to the point where it starts to overflow out of the drain pan and leak out of the air handler.

The combination of the warm air being drawn into the air handler and the moisture in the condensate system means that mold, algae, and slime often start to form inside the system. Over time, this can build up to the point where it begins to clog the drain line and lead to water overflowing from the drain pan. If the system is clogged, you will typically need to hire an AC technician to unclog it, as it usually requires specialized equipment.

If the condensate line that leads out of the air handler is damaged or there are any loose pipe fittings, it can also result in water leaking out and starting to pool up around your furnace. The same can also happen if the floor drain that the condensate pipe empties out into is clogged and starts backing up.

Drain Pan Is Leaking

The drain pan itself can also crack, rust, or otherwise become damaged with age. This will lead to water dripping out of the bottom of the pan and eventually starting to leak out of the air handler. In this case, the solution is to either repair or replace the drain pan. Unfortunately, some systems have the drain pan welded in place. This means you will need to replace the entire evaporator coil assembly if the drain pan is leaking and can’t be repaired.

Evaporator Coil Is Frozen

Air conditioners can also leak if the evaporator coil freezes up, which can happen for a variety of different reasons. If the coil ever does freeze, more and more ice will continue to build up on it until you shut your AC off. Once the AC is off and the coil begins to thaw, it can sometimes result in more water entering the condensate system than it can handle and thus cause the drain pan to start to overflow.

Louisville’s HVAC Pros

At Element Air LLC, our certified technicians can help you overcome AC leaks or any other problems. We service and repair all types of air conditioners as well as furnaces in Louisville, KY, and the surrounding areas. We also specialize in heating and cooling installation. For more information or to schedule a service appointment, give us a call today.

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