Cleaning Condensate Lines

In the southeast, it is a given that the evaporator condensate line will get clogged with slime. The only questions are how long will it take and how messy will it be to clean up? What we often did in the past was to cut out the section of drain near the coil, blow out the drain line, and rebuild the drain with new PVC ells and pipe. However, that means the owner is constantly paying for you to rebuild something that should be cleanable. That is why every evaporator condensate line should have a way to open the drain to facilitate cleaning. In fact, this is now required in the most mechanical codes. You can add cleanout spots by replacing ells with tees, or by using a manufactured product made just for that purpose. Rectorseal and MSD Research both market drain cleanout devices which make complying with the mechanical code and cleaning the drain easier. Ideally, you should be able to clean out the line in both directions – from your cleanout to the evaporator and from your cleanout to the outside.

A Gallo gun using CO2 charges works well for blowing out the drain line. Nitrogen does a good job too, but getting a nitrogen cylinder to the cleanout spot can be difficult. Another option is a sludge sucker. It uses nitrogen to create a vortex, which sucks the condensate and goo out of the drain line. The sludge sucker typically connects to the drain outlet. Some techs use wet vacs and connect to the drain outlet, or to points on the condensate cleanout. Even if the drain is not stopped up, clearing the evaporator condensate line should be part of normal service. Don’t make the customer call you back later because the condensate line plugged up.