If your home's central air isn't working at all, check the main electrical panel in your house. It could just be a tripped breaker or blown fuse. If that's the issue, just reset the breaker or replace the blown fuse. Your thermostat setting could be another reason why your central air isn't working.
The main reasons your AC unit outside is not turning on could be something that has tripped the circuit breaker, something is blocking the fan's airflow, or the condensing unit is damaged. Other potential issues could be the thermostat isn't set correctly or the compressor could be malfunctioning.
Checking basic thermostat settings, power supply components, and air filter conditions are essential to troubleshoot why an AC unit isn't turning on. More advanced issues requiring professional attention include faulty wiring, a malfunctioning outdoor unit, a bad capacitor, or incorrect thermostat calibration.
Check your circuit breaker if your AC is not turning on. If the circuit breaker has tripped, you will need to reset it for the air conditioner to start working again. If your circuit breaker does trip, here's how to reset it: Locate your main circuit breaker and switch it back to the "On" position.
In the majority of cases, your AC system will return to functioning normally after this breaker reset. It's important to know that this isn't an instant fix and may take up to an hour to get back up and running as normal again.
Inadequate Maintenance. Dirty Filters and Coils: Can cause the system to malfunction and lead to premature compressor or fan failure. Solution: Change filters regularly. Ensure filters fit securely to prevent air bypass.
It Won't Turn On
Check your breaker box for a blown breaker or tripped fuse. You may be able to fix this AC issue with the flip of a switch. If that doesn't do the trick, check the wiring in your thermostat. A loose or frayed wire could also prevent your unit from turning on.
Absolutely. While it may seem like a small part of your HVAC system, the thermostat plays a crucial role in ensuring your home stays cool and comfortable.
Most modern thermostats will have a clearly marked reset button inside the panel. It's usually small and recessed, so you might need a pointed object like a paperclip to press it.
Resetting your thermostat is often all that's necessary to get it working again. A tripped circuit breaker is another common reason why your AC won't turn on. Using too many appliances at once can trip the circuit breaker. This is also common when there are power surges after a big storm.
Check these issues when the unit won't kick on: Check the thermostat and adjust the settings if it isn't set to Cool and an appropriate temperature setting to call for cooling. Examine the house circuit breakers for the AC unit and reset any tripped breakers. Check the air filter and replace the filter if it's dirty.
Blowing the fuse cuts the power to the unit to prevent electrical damage. If your AC has shut down and won't start again, especially if you've noticed odd electrical behavior immediately before the shutdown, chances are the fuse has done its job and will need to be replaced.
Connect the red wire of the multimeter to the red wire of the thermostat and the black wire of the multimeter to the black or white wire from the thermostat. A functioning thermostat should have readings close to zero or zero. If not, there is a problem with the thermostat.
Replacing a Thermostat. You'll pay between $15 and $300 for the unit in addition to labor ($65 to $100 per hour) to replace an old thermostat with a new one. However, installing a brand-new thermostat is more involved and, therefore, more expensive.
Air Conditioner Won't Turn On
Be sure the thermostat is set to “cool” mode and the temperature is set low enough to call for the A/C to come on. Look for a tripped circuit breaker or blown fuse. If you're satisfied that the system is getting power, a faulty thermostat may be preventing the system from turning on.
Reset the AC Using the Isolation Switch
The isolation switch looks like an ordinary light switch with a knob. Once you locate it, turn the knob to the off position and leave it for at least 30 minutes up to an hour. This will allow the electrically operated components in the AC to reset.
There are a number of reasons why your AC unit may stop working unexpectedly, including electrical problems, blockages, thermostat issues, and more. Troubleshooting includes checking your circuit breakers, thermostat settings, and replacing your air filters.
Shut off your system by hitting the isolation switch, wait 30 to 60 minutes and then turn it back on. This manual reboot fully disconnects your AC unit from power, allowing all electrical components to reset.
Circuit breakers can be found in homes, businesses, and industrial facilities. They are typically located in the main electrical panel, which is typically located in the basement or garage.