3 Reasons Why Air Handler is Leaking Water

The air handler unit in your air conditioner has the sole function of circulating air around the home without changing the temperature. You might experience problems with your AC unit if your air handler is leaking, so what usually causes this, and can it be fixed? 

Your air handler is leaking water because you have a dirty or faulty condensate drain pipe. Other causes include a dirty air filter,  a bad drain pan, a dirty evaporator or low refrigerant. Thankfully, most of the fixes are relatively simple. 

This article will guide you on the most common causes of an air handler leaking water, with a few tips on how you can solve each problem. 

1. Dirty Condensate Drain Pipe

The most likely cause of any leakage in an air handler is having a dirty condensate drain pipe. Every air handler has a condensate pipe to convey water from the indoor air. Dirt builds up little by little as water passes through the pipe, and in time, traces of minerals, dirt, and debris from the water will stick to the pipe. 

When the dirt and debris block the pipes, it eventually blocks the moisture coming out of the house. Now, the HVAC system is working harder to drain more moisture from the air, but with nowhere to go, the moisture accumulates and causes leaks

How To Fix?

If the cause of your air handler leaking is a clogged drain pipe, then it is an easy fix that you can solve independently. You can clean the drain pipe with a wet or dry vacuum. 

This process is relatively straightforward, but it still requires some steps to ensure you do not damage the drain. Here are the steps to follow:

  1. Put on a face mask, as the smell can be awful.
  2. Turn off the air conditioner for safety reasons.
  3. Identify the pipe you want to clean. You can check below the air handler for any lines connected to it. 
  4. Clean all parts of the pipe thoroughly. Before you use the vacuum, ensure you use a clean rag to clear all debris at the entrance and around the line. After that, use the vacuum to remove the clogged part, and if you can, clean off the residue left behind with a damp cloth. 

You can check this YouTube video to get a more visual representation of the process:

You need to contact a technician if your vacuum doesn’t do the trick. The technician will have a vacuum designed for cleaning pipes, and they can even help to prevent any future clogging.

Read: Does Air Handler Have Filter?

2. Dirty Air Filter

Depending on the HVAC design, three types of filters may be in your HVAC system. These types include: 

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  • HEPA filters
  • Fiberglass filters
  • Pleated filters

These filters may not be directly inside the air handler, but they affect the working process of the device. The air filter’s job is to stop airborne particles from entering the home. Over a short period, these filters can get dirty and affect the air flowing to the evaporator coils in the air handler, causing leaks. 

How To Fix?

It is possible to clean an air filter, but it’s usually best to replace it altogether.

No matter how good the air filter in your home is, it should be replaced regularly. The perfect timeline for changing your air filters depends on the home traffic, but you shouldn’t keep an air filter for more than three months. Some of the factors that affect how regularly you change air filters include the following;

  • The number of people in your home.
  • The presence of pets.
  • The design of the HVAC system.

Changing the air filter is not exactly challenging if you can identify the location and have the right tools to open the area up. However, a full replacement should be done with an HVAC professional (at least the first time) to avoid mistakes.

Read: Which Side Of Air Filter Faces Out?

3. Faulty Condensate Pump

The design of your HVAC system depends mainly on your home’s setup. If the HVAC system is higher than the home’s drain, you will not need a condensate pump. However, if the HVAC system is at the same level or below the drain, you will need a condensate pump. 

Most condensate pumps are centrifugal and automatically pump the water when it reaches a certain level. When this pump breaks or goes bad, the water will stay at one point, causing leaks. 

How To Fix?

The best thing to do in this situation is to replace the condensate pump altogether. This YouTube video will give you insight into how to check and replace the pump:

However, I strongly recommend that you do not attempt to fix or replace this pump without the help of an expert.

4. Bad Drain Pan

Every HVAC system has a drain pan with the sole purpose of collecting the moisture removed from the air. The drain pan is located below the evaporator coil (in the air handler) to absorb the water. However, you may need a secondary drain pipe in the system if you have a horizontal drain pipe.

There are three materials used to make HVAC drain pans to ensure their longevity, including the following:

  • Stainless steel
  • Polymer 
  • Galvanized steel coated with acrylic

Most drain pans’ designs ensure it works for an extended period, but not forever. Over the years, the drain pan may get damaged or rust due to the volume of water running through the pan. When this aspect of the system fails, the water will leak through the air handler.

How To Fix?

After you have checked the system to be sure that your drain pan is the problem, you’ll need to replace it. The best way to do this is to call an HVAC professional. 

Drain pan damage is a sign that your HVAC system is quite old, so having an expert check the whole system while replacing the pan is never a bad idea. 

5. Low Refrigerant and Dirty Evaporator Coil

The refrigerant of your air conditioning system is the part of the system that controls pressure levels, and when the refrigerant reduces, it reduces the pressure

The reduced pressure of the refrigerant will cause the evaporating coils inside the air handler to freeze, causing leaks when the coils unfreeze. When the frozen moisture on the coils condenses, it may be too much for the drain pan to contain. 

Additionally, if the evaporator coils get dirty, they hinder how the water moves from the coil into the drain pan. 

How To Fix?

Whether the problem is with the refrigerant or the evaporator coil, you need to contact an expert to help in this case. 

If the refrigerant is the problem, you will need an expert to help you fill it to the appropriate point. On the other hand, if the evaporator coils are dirty, you’ll need to give them a good clean.

Final Thoughts

If your air handler is leaking water, it is most likely due to a dirty condensate pipe. This pipe is essential to release trapped moisture, so any buildup will likely cause a leak. 

Low refrigerant levels and a dirty air filter may also cause leaks. It’s usually recommended to contact an HVAC professional to fix any problems you’re experiencing since bad fixes will lead to expensive repairs in the future.