First-Time Homeowner? What You Need To Know About Condensate Lines For Your HVAC Systems

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First-Time Homeowner? What You Need To Know About Condensate Lines For Your HVAC Systems

13 October 2015
 Categories: , Articles

As a homeowner, it's important for you to have an understanding of the various parts of your home's utility systems, including the heating and air conditioning units. One thing that many first-time home owners don't understand is that most HVAC systems produce condensation that needs to be carried away from the units to the drainage system. When problems occur in the drainage system or the condensation lines, it can cause leaks and water damage in your home. Here's what you need to know. 

Where Condensation Comes From

Your home's heating and air conditioning systems can produce condensation. Air conditioning systems generally operate by condensing the air, which makes condensation form. Many air conditioning units produce 5-9 gallons of condensation per day. 

Some furnaces and other heating systems can produce condensation as well, particularly if they are high-efficiency and/or gas-operated. Typically, a 100,000 BTU high-efficiency furnace that is running constantly can produce as much as 0.8 gallons of condensation per hour. That water has to go somewhere. 

Condensation Drains 

Within the systems, there are condensate pans with pumps to pump the water out of the system and into a drain. The pans are designed to collect the condensation and pump the water out once it reaches a predetermined level. They use floating devices that trigger the pump, similar to what is found in a toilet tank.

Typically, floor drains are commonly used, but condensation lines can run to sewer lines or sump pumps instead. The set up depends on where your units are located and which type of drain is the nearest in proximity. For example, heating and/or air conditioning units that are in basements are generally connected to floor drains or sump pump pits. Units located in attics or on rooftops are typically connected to a sewer line. 

Most units have a secondary pan to catch overflowing condensation in case the floating device doesn't trigger the pump to activate. These secondary lines can also be connected to a drain but not necessarily. Sometimes, the secondary catch pan is connected to an alarm that will sound to tell the homeowner that there is a problem with the condensation pans, such as a blockage in the drain line.

If your system does not have a secondary catch pan connected directly to a drain, it would be a good idea to asks your HVAC technician to retrofit your unit with an automatic shut off switch to turn off the unit when the secondary catch pan reaches full capacity. That way, you can avoid the leaks and water damage that would likely occur if the system continues to operate and causes the condensation pans to overflow. 


If the condensation drains do not drain effectively, you may notice puddles unless the secondary pan is directly connected to your home's drainage system. If this is the case, you may never know that there is a problem with the primary pan until there is a clog in the drainage system at some point in the future, such as a clogged sewer main. 

If you do not have a secondary pan or it is not connected to a drain, you will need to troubleshoot the cause of the problem, or you could experience flooding and water damage. Here are a few possibilities for why condensation drains do not drain into sewer lines, floor drains or sump pump pits. 

  • clog in the tubing between the condensation pan and the sewer line, drain or sump pump pit 
  • break in the tubing, possibly from a ruptured line due to freezing and thawing of the condensation 
  • clogged sewer line, floor drain, or sump pump pit 
  • broken internal drain system plug inside your HVAC unit 
  • condensation pan pump failure 

To troubleshoot what the problem could be, you first need to know where your condensation lines are. To learn the setup of your system, ask a professional HVAC technician, like those at A Absolute Plumbing & Heating.

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How dark is your basement? Do you use your basement for things other than storage? Maybe, it is time for you to look into getting some basement windows installed. My website is stuffed with information that I had learned as I completed a full basement renovation. Before the renovation, my basement was nothing but cement floors and cinder block walls. Now, it is the perfect living and game room for my family to enjoy throughout the year. We have more than enough space to host the family gatherings and the setting is bright, comfortable and pleasing to everyone that comes for a visit.