What to Check When Your Air Conditioner Won’t Turn On

man adjusting smart thermostat on wall

Is your air conditioner shutting off right away or refusing to run at all? Fortunately, the problem might be easier to fix than you think. You might not even need to call a technician!


If your air conditioner won’t turn on, check the following items to restore cool air to your home.

1. Did your AC trip the circuit breaker?

Air conditioners require lots of power, and occasionally, they can trip a home's circuit breaker – especially if they coincide with a brief power surge. If your air conditioner is unresponsive, check your home’s circuit breaker panel for a tripped breaker.

2. Is your thermostat unresponsive?

If your thermostat isn’t responding to changes on the dial or its display is just a blank screen, then chances are it isn’t getting power, and you won’t be able to use your HVAC system. An unresponsive thermostat usually has one of these problems:

  • Its batteries are dead.
  • It tripped the circuit breaker.
  • There’s something wrong with the thermostat’s wiring (most digital thermostats are hardwired). For this issue, you will need a technician.

3. Is a power switch turned off?

Your home’s central HVAC system has two power switches. One is located indoors by the furnace or air handler. The other is located by your outdoor AC unit, typically in a metal box on your home’s exterior wall.

When your system receives service, the technician may forget to turn one of these switches back to the “on” position. Flipping these switches back on should restore power to your AC and allow the equipment to run again.

4. Is the air filter dirty?

If your AC runs briefly before shutting off, this is a sign that the equipment is probably overheating and shutting off to protect itself. Dirty air filters are the number one cause of overheating AC equipment. When you keep an air filter in place too long without cleaning or replacing it, dust blankets the filter and blocks air from flowing into your HVAC system. A lack of airflow causes the equipment to overwork itself and overheat.

Remember: the more often you use your AC, the faster the filter will get dirty. During the warmest months of the year, you may need to check on the air filter more frequently than you’re used to.

5. Does your air conditioner need to be reset?

Similar to a computer, sometimes your AC needs a hard reset. This is typically necessary after your AC trips the circuit breaker. Before resetting your AC, we recommend that you be familiar with your air conditioner and verify whether or not resetting the unit will impact your warranty.

Consulting the owner’s manual is the best way to find out how to reset your air conditioner. If you’ve lost the owner’s manual, you can most likely look it up online by searching for your air conditioner’s model number.

6. Is the condensate drain line clogged?

Your air conditioner creates a lot of condensation during the cooling process. This condensation collects in a drain pan and leaves your home through a condensate drain line. Without routine maintenance, this drain line can get clogged with dust and other debris. Consequently, water will back up into the drain and fill the drain pan.

Many newer systems have a safety switch that shuts the equipment off when the water level in the drain pan rises to a certain point. This prevents water from entering your HVAC equipment and damaging it. It also prevents your system from running until you can get the drain line cleaned.


At Logan Home Energy Services, we provide top-quality AC repair services throughout Winston-Salem and nearby areas of Central North Carolina. Schedule your service with us by calling (336) 203-7630 or contacting us online.

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