To reset an AC, turn the thermostat to off, switch the AC breaker off, wait several minutes, then switch the breaker on and set the thermostat back to cool. One reset is reasonable. A second trip means something is wrong and a licensed pro should look at it.
Climate Pros Tucson can match you with a licensed local pro when the reset does not hold.
When is it safe to reset an AC?
It is safe when the system quit once, nothing smells burnt, and the breaker is not hot to the touch. It is not safe to keep resetting a unit that trips again right away, hums without starting, or makes a burning smell. Repeated restarts stress the compressor and can turn a small fault into a costly one.
What are the steps?
- Set the thermostat to off.
- Find the AC breaker in the main panel and switch it fully off.
- Wait several minutes. The manual for your unit lists the wait the manufacturer wants, so check it.
- Switch the breaker on.
- Set the thermostat to cool and a temperature below the room reading.
- Listen for the outdoor fan and compressor to start, and check that cool air comes from the vents.
Before you reset, check the basics: a clean filter, a thermostat with working batteries, and a clear space around the outdoor unit. The monsoon season runs June 15 through September 30, and its dust storms can load a filter or outdoor coil fast. A choked filter or coil can make a system shut itself off on a safety limit, and a reset won’t hold until it’s cleared.
Where is the disconnect on a split system and on a rooftop package unit?
A ground-level split system usually has a gray disconnect box on the wall near the outdoor unit. A rooftop package unit has its disconnect on or near the roof, and the AC breaker in the panel is your safe shutoff from the ground. Flat roofs in a Tucson summer are hot, slippery with dust and a fall risk. Do not climb up to flip a switch. Use the breaker in the panel, and leave anything on the roof to a pro.
What about a reset button on the unit?
Some units have a small red reset button on the compressor or a safety switch. Pressing it is a pro’s job. If you open any panel on the outdoor unit while the power is on, you risk shock.
What if the AC quit after a monsoon power outage?
Storms can trip breakers or interrupt power more than once in a few minutes. Switch the thermostat to off, wait several minutes after power returns, and then follow the steps above. Starting an AC the instant power comes back can short-cycle it. If the unit will not start at all, see AC not working after a power outage.
When should you stop and call?
Stop resetting and call a pro when the breaker trips again, when the unit freezes up or leaks, when it blows warm air after a restart, or when it makes grinding, banging or burning smells. See AC tripping the breaker and AC not turning on for causes. Heat is a health risk in Tucson summers, and the CDC advises older adults to stay in air-conditioned buildings in hot weather and not rely on a fan as the main cooling when it is very hot. If your system is down and someone vulnerable is at home, tell the pro when you call, and review what to do while you wait.
When to call us
For AC repair, the pros we send diagnose the fault and tell you what it needs before the work starts. Browse our Tucson HVAC coverage for the areas we match in. Call (520) 353-2520 and we’ll match you with a licensed local pro.