Wait Five Minutes; Reset a Tripped AC Breaker Once
Power is back but the AC is not. Follow a safe five-minute reset, read the breaker’s behavior, and know whether to call HVAC or an electrician.
For a central air conditioner or heat pump, set the thermostat to Off, make sure house power appears stable, and wait five minutes. Reset the HVAC breaker only if it has tripped, and reset it only once. Do not remove the panel cover or open an electrical disconnect.
| What you find | Next action |
|---|---|
| Thermostat says “Wait” or “Starting Soon,” or “Cool On” is flashing | Leave it alone for at least five minutes |
| Labeled HVAC breaker is tripped | Move it fully Off, wait about five minutes, then switch it On once |
| Breaker trips again or will not stay on | Leave it Off and call for service |
| Smoke, sizzling, a burning smell, visible damage or unusual heat from the panel | Do not reset anything; move away and call emergency services if there is a fire, otherwise call an electrician |
| Lights are unusually dim or bright, or only part of the home has normal power | Keep the AC off and report the supply problem to the utility |
Use this reset sequence
- Make sure restoration appears complete. If power is still switching on and off, leave the AC off. Ready.gov advises disconnecting appliances and electronics during an outage to avoid damage from electrical surges when power returns (Ready.gov).
- Set the thermostat to Off. If its display is blank, replace user-serviceable batteries if that model uses them. Do not remove thermostat wires.
- Wait five minutes. A “Wait” message or flashing “Cool On” can indicate a built-in compressor-protection delay rather than a fault. Honeywell Home says this delay can last up to five minutes, while Trane also describes a delay following power loss (Honeywell Home, Trane). Follow the equipment manual if it specifies a longer delay.
- Look at the labeled HVAC breaker without removing the panel cover. A tripped handle may rest between On and Off. Move it fully to Off, wait about five minutes, and then switch it to On once. Carrier recommends this sequence and says to leave the breaker off for professional inspection if the AC does not start or the breaker trips again (Carrier).
- Set the thermostat to Cool and select a temperature below the room temperature. Allow several minutes for the system to respond. Observe whether the indoor blower and outdoor unit start, but do not reach into either unit.
If the breaker was already On, do not cycle it merely to force a restart. Limit other checks to ordinary user controls: thermostat settings and batteries, a clearly labeled furnace or air-handler switch, and the filter. Do not open the outdoor disconnect, replace fuses, test voltage or touch capacitors.
Decide whom to call
Call a licensed electrician if the breaker will not reset or trips again, the panel shows signs of overheating or damage, or the home has partial power or abnormal lighting. For a partial-power problem, contact the utility first; if it confirms that its supply is normal, keep the AC off and call an electrician. See A House-Only Power Outage Points to an Electrician and How to Tell If a Circuit Breaker Is Bad.
Call an HVAC technician when house power is normal and the breaker stays on, but the system still does not start or cool after the delay. Indoor airflow with a silent outdoor unit, buzzing, repeated clicking, ice or a burning odor also warrants service. An outage immediately before the failure does not, by itself, prove that a surge damaged the AC.
For a window or portable air conditioner, use only the reset procedure in that model’s manual; plug and control-panel designs differ. If indoor heat is becoming dangerous, stop troubleshooting and move to an air-conditioned location or cooling center.