(2019 update) Although this post is still accurate, I have a more updated and detailed version on how to keep your condensate drain line clean here.
So here I am in the sunny state of Florida, and the people are starting to turn on their air conditioning systems again here at the 500 unit apartment complex, and it is time for me myself to go back to some of the HVAC training that I have learned in the past. Being that I am in Florida I do not get much chance to work on heaters, thought this year was a little bit different, as the temperatures here in Florida were a bit colder. But let’s get onto some more hvac training and troubleshooting, particularly keeping that condensate line clear and free of slime sludge and other things that will eventually cause the line to clog up, such as dead lizards and stuff.
So here at the complex our HVAC systems are electric when it comes to the cooling part. It is a split HVAC system, meaning that the air handler, which has the cooling coil inside of it, is located inside of the apartment, and the condensing unit is located on the outside of the apartment. Inside the air handler is a drip pan, where the lines will condensate when the coil is removing the heat from the room, then the condensate drips into the drip pan, then into the pvc piping which leads to the outside, where the condensation will drain.
Now this works quite well but there always seems to be problems with the condensation lines getting clogged up with slime sludge growth, and it tends to build up the most during the ending of the winter month. When the line gets clogged up, the water, or condensation will have nowhere to go anymore, and it will back up into the drip pan and either hit the float switch, thus shutting the air conditioning units down, or the air conditioning will continue to run and flood your apartment, or home. Hopefully you have a float safety switch installed in the air handler, as if it is a newer air handler it is mandatory and up to Florida code that you have one installed on your air conditioning system.
There are a couple of ways that you can clean out condensate lines. One way would be to use a wet/dry vacuum and suck the line out, although this could leave some slime sludge behind, and a couple of months later if not sooner you will have the same problem again. Another way that you can clean out a condensate line is by using a type of air gun, also known as a gallow gun. What it is basically is a gun that you load up with c02 cartridges, you cut the pvc line and insert the gun into the line and blow away. This usually does a fairly good job of cleaning the line out.
Some people will even go as far as pouring bleach or drain cleaner down their condensate line to clean it out, which will also work in some cases. So for the purpose of this hvac training, what is really the best way to clear a condensate line? I use the combination of the gallow gun and at the same time use the wet/dry vacuum outside.
This way I know for a fact that the line is going to be cleaned out. After that I would insert slime tablets into the drip pan, there are lots of brands out there and they will prevent the growth of slime inside of your condensate line, meaning that you should not have as much as a problem getting the line clogged, most require you to use the tablets monthly.
If you have done the above and know that the line is clear, but it is still backing up, you may have to level your air handler. You will also want to make sure that at no point is your drain line rise above the drip pan, if it does it is not going to drain properly unless you have a drain pump that is attached to the condensate line. Hopefully this was enough HVAC training to cure your clogged condensate line problem as it is what I deal with day in and day out and always fix the problem, any questions or concerns drop me a comment and I will get back to you soon!