How to Reset Your AC Unit (and When Not To)
After a power outage, a tripped breaker or a thunderstorm, a central AC sometimes will not start again on its own. A careful reset often brings it back. Here is how to do it safely, and the signs that a reset is not the answer.
Before you reset
- Check the thermostat first: COOL mode, a setting below the room temperature, fresh batteries. See how to reset your thermostat.
- Check the air filter. A clogged filter can freeze the coil and make the system shut down.
- Look for water in the drain pan under the indoor unit. A full pan can trip a float switch that keeps the AC off. See AC leaking water.
How to reset a central AC
- Turn the thermostat to OFF.
- Turn off power: switch off the AC breaker (or breakers) in your electrical panel. Many outdoor units also have a disconnect box on the wall next to them; pull it or switch it off too.
- Wait at least 5 minutes. This lets the system and its safety controls settle.
- Turn the power back on: disconnect first, then the breaker.
- Set the thermostat to COOL a few degrees below the room temperature.
- Give it a few minutes. Many systems have a built-in delay before the outdoor unit starts. See the 3-minute rule for AC.
Does my AC have a reset button?
Some outdoor units and some furnaces or air handlers have a small reset button, but many do not. If you find one, press it once. Do not keep pressing it. A system that needs repeated resets has a problem that a reset will not fix.
When not to keep resetting
- The breaker trips again after one reset. Leave it off and call. That points to an electrical or compressor problem.
- You smell burning or see scorch marks near the unit or panel.
- The outdoor unit hums but the fan does not spin. That is often a failed capacitor. See bad AC capacitor signs.
- There is ice on the copper lines or indoor coil.
- It runs but blows warm air. See AC running but not cooling.
Still not running?
Cowboy's answers 24/7 with our own dispatch on Blanco Road, and you get the price in writing before work starts. See AC repair in San Antonio or our 24/7 emergency HVAC service.
Frequently asked questions
How do I reset my central air conditioner?
Turn the thermostat off, switch off the AC breaker and the outdoor disconnect, wait at least 5 minutes, turn the power back on, then set the thermostat to cool and give it a few minutes to start.
How long should I wait to reset my AC?
Wait at least 5 minutes with the power off. After you turn it back on, many systems wait a few more minutes before the outdoor unit starts.
Why did my AC stop working after a power outage?
A power surge or outage can trip the AC breaker or leave the system in a safety lockout. A careful reset often fixes it. If the breaker trips again, call for service.
Where is the reset button on my AC?
Many central AC systems do not have one. Some outdoor units, furnaces or air handlers have a small red or black button. Press it once, and call if the system needs it again.
Is it bad to keep resetting my AC?
Yes. If the system keeps shutting off or tripping the breaker, something is wrong, and repeated resets can damage the compressor.
Related service: AC repair in San Antonio · 24/7 emergency HVAC · Cowboys Air Conditioning & Heating. Cowboy's AC answers 24/7 at (210) 495-7771.
