Doing Your Part to Keep Your HVAC System Running

A few months ago, my air conditioner completely died. I woke up in the middle of the night covered in sweat, and I didn't know what to do. The next day, I called an HVAC expert, and they came out to inspect my system. It turned out that it had failed because of filthy filters and a clogged return duct, which made me sick to my stomach. I had caused the problem, and I needed to learn how to fix things. My HVAC professional taught me a few easy maintenance techniques that I didn't know before, so that I could maintain my new system. Check out this blog to learn more about HVAC yourself.

Diagnosing Condensate Drain Problems


One of the tasks your air conditioner performs is dehumidifying the air. Water holds onto heat, so extracting as much water from the air as possible helps keep the area cooler. While the A/C unit is designed to safely dispose of the water, sometimes the drain malfunctions, causing leaks and other problems. Here are some of the issues that can develop with your condensate drain and how to repair them.

Water Leakage

One of the most common issues caused by malfunctioning drains on air conditioners is leaks and overflows. For one reason or another, the water is blocked from passing through the drain like normal, resulting in water flowing to places it shouldn't, such as down walls, on floors, and even inside the appliance itself.

Clogs are probably the main reason this issue develops. The combination of warm air and condensation provides an optimal environment for algae to grow. Over time, the algae gets so big or numerous that it stops water from flowing freely through the drainage system. You can tell this is the problem by opening up the air conditioner and inspecting the drain line and/or trap.

Luckily, this particular issue is fairly easy to fix by cleaning the drain system, using a shop vacuum to suck the algae out and flushing the pipe and line with bleach water or hydrogen peroxide to kill any remaining organisms.

Damaged, missing, or misaligned parts in the drain system are other reasons for leaks and overflows. The drain pan may be missing or cracked, allowing water to seep through the machine and into your home. In this case, you'll need to replace the part. Sometimes the issue is the drain pain and line aren't tilted enough to allow the water to flow through naturally, so you'll need to adjust them slightly to fix this issue.


As noted previously, the warm wetness of the condensate drain is the perfect breeding ground for algae, but it can often also be ground zero for mold growth. While mold generally doesn't cause blockages in the drain line, it can lead to other problems. For instance, if it's not caught in time, it can spread to the evaporator coils, reducing airflow. More concerning, people with respiratory issues such as asthma and allergies may experience worsening health problems from breathing in mold spores dispersed by the air conditioner.

Like with the algae growth, eliminating mold is as easy as thoroughly cleaning the system. The challenge is making sure you can access all the affected parts to clear away the disgusting organisms. Be sure to use face protection to avoid breathing in the spores, and let the unit dry completely before putting it back together to avoid kick starting another mold colony. Inspecting and cleaning your unit on a regular basis can help prevent this problem in the future.

Sewer Smell

Central air conditioners are typically installed so that the water from the condensate system drains directly into the plumbing pipes. Because of this, a trap is typically built in to prevent sewer gases from escaping into the environment. The trap is supposed to contain a little bit of water to keep the drain area moist and sewer gases in the pipes. Unfortunately, sometimes the drain trap dries out because of improper installation or the drain was used so infrequently that the water in it naturally evaporated.

If your home fills with a terrible sewer smell each time you turn it on, this is likely the problem. One way to fix it is to pour water down the drain to remoisten the area, which may be the best option if the trap is dry because of disuse. Another thing you can try is to adjust the drain line to ensure the water is flowing into the drain properly. A third thing to try is to replace the drain seal if it appears it has deteriorated and is no longer functioning properly.

For more information about repairing an issue with your condensate drain system or help making repairs to your air conditioner, contact an AC maintenance professional.


1 November 2017