Don't Let These Condensate Issues Send You Down The Drain

Posted on: 18 June 2015

As your air conditioner works hard to remove latent heat from the surrounding air, it also removes moisture by condensing it from vapor to liquid form. The liquid condensate drops into a drip pan below the evaporator coil, where it's eventually channeled through a drain into the nearest drainage point.

There are a lot of things that can get in the way of proper condensate drainage. Read along and find out which problems could lead to drainage failure and what you or your HVAC technician can do to fix these problems.


Blockages can occur when dirt, dust and debris clog up the condensate drain, causing the water to back up and eventually overflow out of the drip pan. When that happens, you might see water pool around the bottom of the A/C cabinet. You can easily resolve blockages through the following:

  • Start by removing visible debris from around the drain inlet. You may be able to fish out some of the shallow crud within the inlet with your own fingers. Of course, it's always a good idea to wear protective gloves while clearing the drain.
  • For deep clogs, break them up using a condensate drain brush or a long piece of plastic tubing. Carefully work out as much of the clog as possible without breaking the drain line itself.
  • If necessary, use compressed air to blow out the drain line. Be careful, as doing so could cause a drain line connection to break.

It also pays to make sure the condensate drain lines are properly installed. Not only should all condensate drains have their own drain lines, but these lines should also have a steep enough angle throughout its run to allow condensate to quickly drain away from the drip pan.

Mold Growth

Mold growth is one of the most common problems faced by your A/C system and for good reason. The area housing the evaporator coil happens to be an ideal spot for mold growth – it's dark, damp and warm enough to facilitate it. As mold spores settle on the condensate drip pan, mold growth can proliferate throughout the area.

Not only can mold growth create blockages that prevent condensate from draining properly, but it can also spread throughout the entire home via the HVAC system. Mold spores can also trigger allergy symptoms and cause respiratory issues in those most vulnerable, including children and elderly adults.

Here's how you can resolve mold growth issues in and around the condensate drip pan:

  • After thoroughly cleaning the pan and condensate drain, pour a half-cup of bleach or white vinegar down the drain. Doing so will disinfect the drain and kill off any remaining mold growth.
  • Use pan tablets to prevent mold-related blockages from happening. These tablets can also help prevent scale buildup as well as control odors. Most tablets are designed to be used on a monthly basis.
  • Consider investing in an ultraviolet (UV) lamp near the evaporator coil. UV lamps emit the same spectrum of radiation as natural sunlight, which works to destroy bacteria and mold spores on a molecular level.


Aside from blockages and overflow issues caused by debris and mold growth, there's also the danger of leaks in the drainage line itself. These leaks are often caused by small cracks in the PVC piping or loose, ill-fitting connections. Leaks can even come from the condensate drip pan itself, especially if it's suffered from the effects of rust and corrosion.

The following shows how you can check for leaks:

  • Carefully check the condensate drain pipe for signs of cracks and other damage. Most cracks can be repaired with a little sealant. If chunks of existing pipe are missing, then it's better to replace the entire pipe section.
  • Make sure all connections are sealed with the proper glue. Without it, the connections can come loose and allow the pipe to leak condensate.
  • Check the condensate drip pan for signs of rust and corrosion, as well as cracks and other damage. If the pan is damaged, it'll have to be replaced entirely.

These tips can help you resolve just about any condensate leak issue you have with your A/C system. Should you have any other questions you can contact a professional or click here for info.


HVAC For The Layman

Do you remember the last time your air conditioner died? Although you might have been tempted to write off the problem as a simple quirk, serious air conditioning issues might mean that your family gets stuck living in a hot, humid, uncomfortable environment. I have been a homeowner for a long time, and you wouldn't believe how many times I have come across issues with my HVAC systems. I want you to know how to recognize the early signs of trouble, which is why I decided to put up this page. By reading here, you might be able to learn the intricacies of HVAC in layman's terms so that you can get things resolved as quickly as possible.