AC not cooling? What to check before you call
Most of these checks take a minute and need no tools. Run through them in order, and if the system still isn’t cooling, you’ll be able to tell us exactly what you saw.
Six checks, in order
Start at the thermostat and work your way outside.
Thermostat
Make sure it’s set to cool, not heat or fan, and that the setpoint is a few degrees below the room temperature. Set the fan to AUTO, because on ON the blower keeps running between cooling cycles and the air at the vents will feel warm. If the screen is blank, replace the batteries.
Breakers and the disconnect
Check the breakers for the air handler and the outdoor unit, and the disconnect switch in the box beside the outdoor unit. A tripped breaker can be reset once. If it trips again right away, leave it off and call, because something on that circuit needs a professional.
Filter
Pull the filter at the air handler or the return grille and hold it up to the light. A filter you can’t see through can choke off airflow badly enough to freeze the coil.
Outdoor unit
With the thermostat calling for cooling, the outdoor fan should be spinning and you should hear the compressor running. If the unit hums and the fan sits still, turn the thermostat off. A failed capacitor is a common cause, and it’s a repair for us.
Ice
Look at the larger copper line where it enters the outdoor unit, and at the indoor coil if you can see it. Ice means the coil got too cold, usually from poor airflow or low refrigerant. Switch the thermostat to off, let it thaw on its own, and don’t chip at it.
Water and the float switch
If the system is dead at the thermostat and there’s water in the pan under the air handler, the float switch has probably shut it off because the drain is clogged. The switch is one of the backups Florida code allows for exactly this situation. Leave the clearing to a technician.
What the symptoms usually point to
Warm air and a silent outdoor unit
No power reaching the outdoor unit, a float switch that has tripped, or a thermostat that isn’t calling for cooling.
Outdoor unit humming, fan not turning
Most often a failed capacitor. Turn the system off and call.
Ice on the lines or the coil
Restricted airflow from a dirty filter, or low refrigerant from a leak.
Runs all day and never catches up
Low refrigerant from a leak, or a dirty outdoor coil that can’t get rid of heat.
Cold but clammy
Often an oversized system that shuts off before it has pulled the moisture out of the air.
Water on the floor
A clogged condensate drain, with a float switch that’s missing or not working.
Where the float switch lives
Look at the base of the air handler and you’ll usually find the drain coming out as white PVC, often with a clear cleanout cap and a small float switch mounted in the line or in the pan. When water backs up, the float rises and cuts the system off.
A system shut down by its float switch looks broken, but it’s doing exactly what it was installed to do. The repair is clearing the drain and working out why it clogged.
What not to do
Don’t chip ice off a frozen coil. The fins and tubing are thin metal, and a puncture turns a thaw and a cleaning into a coil replacement.
Don’t keep resetting a breaker that trips. Don’t pressure-wash the outdoor coil either, since high pressure flattens the fins. And leave refrigerant to a technician: if a system is low, it has a leak, and adding more doesn’t fix that.
When to call us
If the thermostat, the breakers and the filter all check out and it still isn’t cooling, call or text and tell us which of these checks you ran and what you found. ’The outdoor unit hums but the fan won’t spin’ or ’there’s water in the pan and the thermostat is dead’ tells a tech far more than ’it’s broken,' and it means the right parts come on the first trip.
Condo owners whose outdoor unit is on the roof may not be able to see it at all. That’s normal, so skip that check and let us know where the unit is when you call. For more on how we handle the visit, see AC repair in Naples.
No cooling? Call or text us.
Or open the chat button. Tell us what the system is doing and where the equipment sits, and we’ll set up a visit.
Need ac repair?
AC repair is what we do every day. Call or text and tell us what the system is doing.
Questions we get
Is it safe to run the AC with ice on it?
No. Switch it off at the thermostat and let the ice melt. Running a system with a frozen coil can damage it.
Why does my AC run but the house stays warm?
The usual suspects are a dirty filter, a dirty outdoor coil, and low refrigerant from a leak. If the filter is clean and the outdoor unit is running, it’s time for a diagnosis.
Can a clogged drain really shut off my AC?
Yes. Florida code requires a backup for a clogged primary drain, and one of the allowed options is a water-level switch that turns the equipment off when the drain backs up, so the system stops before the pan overflows.
Should I turn the AC off while I wait for you?
Yes, if there’s ice, water on the floor, a humming outdoor unit or a breaker that keeps tripping.