The air conditioner was running fine. Then it stopped, and there is water around the air handler or a stain spreading on the ceiling below it. Nothing sounds broken. Nothing smells burnt.
Nine times out of ten in South Florida, this is a clogged condensate drain line, and it is the most common service call we run.
Where all that water comes from
Your AC does two jobs here. It cools the air and it pulls moisture out of it. In a humid South Florida summer a single system can pull 5 to 20 gallons of water out of your house in a day, depending on the size of the home and how hard it is running.
That water condenses on the cold evaporator coil, drips into a pan underneath, and leaves the house through a narrow PVC drain line. The whole system depends on that one small pipe staying clear.
Why it clogs here more than anywhere else
Warm, wet, dark, and full of standing water is exactly the environment algae likes. In our climate a slimy biological sludge builds up inside that line over a season and eventually plugs it. Dust pulled through the system, insulation fibers, and the occasional insect add to it.
Once the line blocks, the water has nowhere to go. It backs up into the pan, the pan fills, and then one of two things happens.
The float switch is doing you a favor
If your system has a float switch, and most do, it senses the rising water and shuts the whole air conditioner off on purpose. That is why the AC stops for no apparent reason. It is not broken. It is protecting your ceiling, your drywall, and your floors from a few hundred gallons of water.
If your system does not have a working float switch, you find out a different way: water coming through the ceiling, or a soaked closet. That repair is dramatically more expensive than the drain line ever would have been.
The two minute check before you call anyone
There are a few things worth looking at yourself.
Find the drain pan under the air handler and see whether it is holding water. Look for the drain line exit outside, usually a white PVC pipe near the condenser or coming out of a wall, and check whether anything is dripping from it while the system runs. If the pan is full and nothing is coming out outside, the line is blocked. Check the breaker too, and confirm the thermostat is still set to cool and below room temperature. Sometimes the answer really is that simple.
A wet or dry shop vac held to the outside end of the line will sometimes pull the clog free. It is worth trying. If it works, you just saved yourself a service call, and we would rather tell you that than not.
When it needs a tech
If the line will not clear, if it clogs again within a few weeks, if the pan is cracked or rusted through, or if there is water damage to the ceiling or wall, that is the point to call. A repeat clog usually means the line has a sag holding water, a slope problem, or a section that needs to be reworked rather than just cleared.
How to stop it happening again
This is the part most homeowners never hear. A clear drain line is maintenance, not a repair. Flushing the line, treating it to slow the algae growth, confirming the float switch actually works, and checking the pan for corrosion are all part of a proper tune up, and doing it twice a year in this climate is what keeps you from finding water on the floor in August.
It costs very little to prevent and a great deal to clean up after.
A Kool Saver is a licensed Florida mechanical contractor serving Miami Dade, Broward, and Palm Beach. If your system has shut itself off or you are seeing water where it should not be, get a free quote, or read more about our AC maintenance and repair services.