When the AC stops cooling on a hot Central Florida afternoon, it's natural to want to call right away, and that's fine. We're open 24/7. But some of the most common causes are simple, and you can check them in a few minutes without any tools. Here are seven things to look at first.
One ground rule: anything beyond resetting a breaker, changing a filter or clearing a drain line, such as electrical parts, refrigerant or opening up the units, should be left to a licensed technician.
1. Check the thermostat
It sounds obvious, but it happens to everyone. Make sure the thermostat is set to Cool (not Heat, Fan or Off), the set temperature is below the current room temperature, and no schedule or vacation hold is overriding it. If the screen is blank or dim, replace the batteries if it uses them. With a smart thermostat, check the app and its Wi-Fi connection, since settings can change after an update or when someone else in the house adjusts them.
Also check the fan setting. If it's set to On instead of Auto, the blower runs constantly, even between cooling cycles, which can feel like warm air coming from the vents.
2. Look at the air filter
A clogged filter is one of the most common reasons for weak cooling. It chokes airflow, makes the system work harder and can even cause the coil to freeze. Pull it out and hold it up to the light. If you can't see light through it, replace it. Because air conditioners here run most of the year, it's smart to check your filter monthly.
3. Check the breakers
Most systems have two breakers in the electrical panel: one for the indoor air handler and one for the outdoor condenser. Storms and power surges can trip them. If one is tripped, switch it fully off and then back on, one time only. If it trips again, leave it off and call us. A breaker that keeps tripping points to an electrical problem that needs a professional. Also look at the outdoor disconnect, the small box on the wall near the condenser, and make sure it hasn't been switched off.
4. See if the outdoor unit is running
With the thermostat calling for cooling, go outside. You should hear the unit running and see the fan on top spinning. If the fan isn't spinning but the unit is humming or buzzing, turn the system off at the thermostat and call us. That often points to a failed capacitor or fan motor, and running it that way can damage the compressor. Never poke anything through the fan grille.
While you're out there, make sure the unit isn't smothered by shrubs, vines, grass clippings or leaves. It needs open space around it to release the heat it removes from your home. If you clear debris, turn the system off first, and trim plants back so air can move freely on all sides.
5. Make sure vents and returns are open
Walk through the house and check that supply vents are open and not blocked by furniture, rugs or curtains, and that return grilles aren't covered. Closing a lot of vents doesn't save energy. It reduces the air moving across the coil and can cause poor cooling or even ice.
6. Look for ice
Check the larger copper refrigerant line at the outdoor unit and, if you can see it, the area around the indoor coil. If you find frost or ice, turn cooling off and set the fan to On so it can thaw. Don't chip at the ice. Ice usually means low airflow or a refrigerant problem. We explain the causes and what to do in Why is my AC freezing up in Florida humidity?
7. Check the condensate drain and float switch
Your AC pulls a lot of water out of Florida air, and that water leaves through the condensate drain line. Algae and sludge love that warm, wet pipe. Many systems have a float switch, a safety device that shuts the AC off when the drain backs up so water doesn't damage your home. If the system won't come on and you see water in the drain pan or around the air handler, a clogged drain may be the reason. Our FAQ walks through how to clear a drain line safely, starting with turning off the power. If the water keeps backing up, give us a call.
When to stop and call us
Turn the system off and call a professional right away if you notice:
- A burning smell, smoke or scorched wiring
- A breaker that trips again after one reset
- An outdoor unit that hums or buzzes but the fan won't spin
- Hissing or bubbling sounds, or ice that keeps coming back
- Water leaking that you can't stop
- Air from the vents that still isn't cool after you've checked everything above
These usually involve electrical parts, refrigerant or the compressor, and they need to be tested with the right tools. Our AC repair technicians find the actual cause and give you the price before any work starts. If you're weighing a big repair on an older system, our guide to repairing or replacing an AC in Central Florida can help.
Prevention beats a hot afternoon
Many of the problems on this list, like clogged drains, dirty coils and worn capacitors, are exactly what a tune-up is designed to catch early. Our Comfort Club plans include two maintenance visits a year with drain line cleaning at every visit, or you can book a one-time AC tune-up.
