Condensate drainage isn't a topic that many homeowners spend a lot of time considering. Your home's air conditioning system removes humidity, but where does that moisture go? The answer is the moisture condenses onto the evaporator coil as the coil transfers heat energy to your refrigerant. When everything works as it should, this condensate falls into a pan and drains away.

However, condensate drainage is more than just a nice-to-have feature. Without adequate drainage, your system may experience several substantial failures. The earlier you recognize the warning signs of a problem with your air conditioner's condensate drainage system, the more likely you'll avoid issues arising from an overflowing condensate pan.

What Happens When Condensate Can't Drain?

Residential air conditioners typically run in cycles. The time for a cycle will vary based on your air conditioner and the conditions in your home, but it's normal for most systems to run a few times per hour. While running, condensate will collect on the evaporator coil. In between cycles, that condensate will drain into the condensate pan.

These cycles are crucial to maintaining proper humidity levels in your home. If your system continued to run in between cycles, the blower would pick up moisture from the evaporator and redistribute humid air throughout your home. However, problems with your condensate drain can create a similar situation, and you may initially notice unusually high humidity levels in your home.

As the problem progresses, additional issues can develop. Your system may begin to short cycle if excess condensation freezes on the coils. Most systems also contain condensate drain switches that will stop the system when condensate levels become too high. If there's no drainage, the system may not turn back on. Finally, water may begin to pool near the base of your air handler unit.

Why Do Air Conditioners Develop Drainage Issues?

The most basic drainage system design for an air conditioner consists of a drain pan and a pipe that gravity feeds into the home's plumbing or to an outdoor location. You will typically find these systems in attic air conditioners or in any location where the air conditioner is above the home's drain system. On the other hand, basement air conditioners often require pumps to feed condensate into the plumbing.

Clogs in the condensate drain are the most common failure point, but issues can also develop with the pump or the float switch that engages the pump. In some cases, the condensate drainage overflow switch can also fail. This switch acts as an emergency shut-off, and a faulty switch may command your AC to shut down even when no other drainage problem is present.

Regardless of the underlying cause, you should never ignore a condensate drainage issue. Increased humidity levels can create a breeding ground for mold and may also lead to rust inside your AC cabinet. Since most drainage issues are relatively cheap and easy to address, there's no reason not to contact an HVAC technician when you notice a problem.

For more information on air conditioning repair, contact a professional near you.