Why Your AC Unit May Not Be Turning On: Common Issues and Solutions

Tripped Circuit Breaker:

Sometimes, a power surge or an overload can cause the circuit breaker that powers your AC unit to trip. This is a safety feature designed to protect your electrical system. To resolve this, locate your home’s electrical panel and check if the breaker linked to your AC is in the “off” position. If it is, reset it by switching it back to the “on” position. If the breaker continues to trip, this could indicate a more serious electrical issue that needs professional attention.

Thermostat Settings:

The thermostat acts as the command center for your AC unit. If it’s not set correctly, your AC won’t turn on. Ensure that the thermostat is set to “cool” mode and that the temperature is set lower than the current room temperature. If it’s a programmable thermostat, verify that the schedule settings are correct and that it’s not set to turn off at certain times.

Dead Batteries in the Thermostat:

If you have a battery-operated thermostat, the batteries might be dead or low. This can prevent the thermostat from communicating with the AC unit. Replace the batteries and see if this resolves the issue. It’s a simple fix that is often overlooked.

Blown Fuse:

AC units have fuses in the condenser unit (outside) or air handler (inside). A blown fuse can stop your AC from turning on. To check this, you may need to access the fuse box or control board of your AC unit, which might require some electrical knowledge. If you’re not comfortable doing this yourself, it’s best to call a professional.

Faulty Wiring:

Over time, wiring connections can become loose or damaged. Faulty wiring can interrupt the electrical flow to your AC unit, preventing it from starting. Inspect the wiring for any visible damage or loose connections. Again, if you’re not experienced with electrical work, it’s safest to contact a professional technician.

Motor or Capacitor Issues:

The compressor motor and capacitor are essential components of your AC unit. If the motor has burnt out or if the capacitor is failing, the AC unit may not start. Signs of a faulty capacitor can include a humming noise or the unit struggling to start. These parts can be dangerous to handle without proper knowledge, so it’s recommended to seek professional help.

Refrigerant Leak:

The refrigerant is the lifeblood of your AC system. If there’s a leak, the refrigerant level can drop too low, triggering safety mechanisms that prevent the unit from operating to avoid further damage. You might notice reduced cooling efficiency or ice buildup on the coils. Fixing a refrigerant leak is a job for a licensed HVAC technician who can safely handle the chemicals and repair the leak.

To Conclude: 

By methodically checking for common issues such as a tripped circuit breaker, incorrect thermostat settings, dead batteries, blown fuses, faulty wiring, motor or capacitor problems, and refrigerant leaks, you can potentially identify the problem and restore your cool sanctuary. Each of these issues has its unique signs and solutions, some simple enough to handle on your own, while others may require the expertise of a professional HVAC technician. 

Remember, timely maintenance and prompt attention to these issues can not only bring immediate relief but also extend the lifespan and efficiency of your AC unit. So next time your AC doesn’t turn on, don’t sweat it—follow these steps and consider calling in a professional to ensure your home stays comfortably cool all season long.

If you’ve checked these potential issues and your AC unit still isn’t turning on, it’s best to reach out to a professional HVAC technician. They have the tools and expertise to diagnose and fix more complex problems.

Written by: Koba Razmadze.

Koba Razmadze is the owner of RK Mechanical Air Services and holds a C20 Contractor License (#1064548). With over 35 years of experience in the HVAC industry, Koba specializes in both residential and commercial HVAC systems, ensuring expert-level service and advice.