A condensate drain line clog is one of the most common AC calls in Port Charlotte, and it is almost always algae. Our systems pull gallons of water out of the air every day in summer, and that warm, dark PVC line is a perfect place for slime to grow.
When the line backs up, one of two things happens. If there is a float switch in the pan or line, it shuts the AC off and the house warms up. If there is not, the pan overflows and water ends up in the ceiling, the closet floor or the garage. We see stained ceilings under attic air handlers every week of the summer.
We clear the line with a wet vac from the outdoor end, then flush it with water and a cleaning treatment from the indoor side. We check the trap, confirm the line has proper slope and look for sags where water sits. If there is no cleanout tee near the air handler, we add one so the line is easy to service.
The Florida mechanical code calls for a secondary drain pan or a float switch on air handlers installed where an overflow would cause damage, such as in an attic. If yours is missing or not wired, we install one.
For homes with a history of a condensate drain line clog, we recommend treating the line a few times a year with a cup of white vinegar through the cleanout. Line treatment is part of every AC tune up we do.