To find out why your AC device won’t turn on, first make sure the circuit hasn’t tripped. Next, make sure your thermostat is working properly. If so, go outside to check the condensate pump and electrical connections. Finally, try testing the device’s dual-function capacitor. If you aren’t sure, we always recommend reaching out to a reputable HVAC contractor to get a professional opinion.
Once you figure out why your air conditioner won’t turn on, the repair can often be surprisingly easy. We’ll walk you through the troubleshooting steps and the steps you can take to resolve the issue you’re experiencing. You can now restart your air conditioner. First, go to your circuit breaker.
Check the Circuit Breaker
Your central electrical panel distributes power from your main distribution line to every electrical appliance in your home. This can include both your thermostat (if it is plugged in rather than running on battery power) and your air conditioner itself. Circuit breakers trip to protect your devices when they detect a dangerous power surge. Tripped circuit breakers cut off all power to the device they are protecting until you reset them.
Tripped circuit breakers are surprisingly common. You may not notice a circuit breaker tripping until you notice the light won’t turn on. Find your main electrical box and look for tripped circuit breakers. The tripped circuit breaker is moved to the “OFF” position instead of the “ON” position and may also be indicated by a red warning sign. Simply turn the circuit breaker back on and see if your air conditioner restarts.
Test the Thermostat
If your thermostat isn’t working properly, it may not be sending the correct cooling instructions to your air conditioner. Even if the air conditioner works perfectly, it never turns on because it doesn’t know what you ask it to do! Defective thermostats are usually easy to spot. If the screen does not turn on, does not respond to input, or programming is immediately lost, there is an error. Try replacing the batteries or tripping a circuit breaker again.
If all is well with your thermostat, there is a relatively easy way to test it. First, turn off the power to your thermostat. You will need a screwdriver. Remove your thermostat and open the access panel on the back. Locate the red and green wires, unscrew them from their terminals and manually wrap them together. Then disconnect the wiring and turn the circuit breaker back on. If the air conditioner starts, you need to replace the thermostat.
Clear the Drain Line
With the access panel open, locate your unit’s condensation pump. This pump removes moisture that accumulates in the unit’s condensation pan by pumping it through the drain line. This drain line safely drains condensation outside the device. However, if the drain line is clogged, the pump cannot pump out the condensate. Instead, it accumulates inside the AC device until the device’s safety features prevent it from activating.
Cleaning the drain pump from blockages is relatively easy. First turn off the mains power. Locate the tub, pump, and drain line. If you have a handheld vacuum, vacuum up any excess moisture in the container. Then disconnect the drain line and vacuum the blockages inside with the handheld vacuum cleaner. If you don’t have a handheld vacuum, use water or compressed air. After assembling the components, add some moisture back into the tub to ensure everything is working properly.
Replace the Dual Run Capacitor
Dual-run capacitor malfunctions (or dual-round capacitors) are among the most common AC problems. These capacitors are located in the access panel of the AC unit and provide power to the fan and compressor at the same time. If they stop working, the fan and compressor cannot start the cooling process. Locating, testing, and even replacing the dual run capacitor in your AC unit is easy. Here’s how to do it step by step:
What you need: a screwdriver or socket wrench (depending on the device), pliers and a duster.
- Turn off both the power to your AC unit and your thermostat.
- Open your access panel using the screwdriver or nut driver. Don’t lose the screws!
- Locate the Dual Run Capacitor. It’s usually located on the upper component box within the access panel. Dual Run Capacitors are cylindrical, bolted to a holder, and connected to the electrical supply via three differently-colored wires.
NOTE: The Dual Run Capacitor may be located next to another capacitor. In that case, look for the capacitor labeled with “COM,” “FAN,” and “HERM” inputs. - Dust off the upper component box with your duster. Check the wires for signs of damage while you’re at it.
- Unscrew the Dual Run Capacitor from its mount and remove it.
- Check the labeling on the side of the capacitor to find the capacitor’s microfarad rating (which will be labeled “uf”). This is the rating you’ll need to know to buy your replacement capacitor. Take a picture, write it down, or take the actual capacitor with you when you buy a replacement.
- Buy your replacement capacitor either online or at your local hardware store. Make sure you get one with the same microfarad rating.
NOTE: Your new Dual Run Capacitor may be smaller than your current one. That’s not necessarily a mistake. You may need to adjust the capacitor mount when reinstalling. - User the pliers to disconnect the capacitor from the three wires connecting it to the power supply. Make sure you remember which wire goes where (consider taking a picture with your phone).
- Connect each wire to the new capacitor.
- Re-mount the new capacitor back in the upper component box. You may need to adjust the mount or re-mount the capacitor yourself.
- Restart your power and adjust your thermostat to test the new capacitor. It may take 10-15 minutes for your AC unit to restart.
If you’ve tried each of these general troubleshooting steps and still can’t turn on your air conditioner, don’t panic! These steps do not exhaust all possible quick solutions; Just the ones you should try for yourself.
Whether you have exhausted your troubleshooting options or not, you can always call Tudi Mechanical Systems for assistance. Our professional HVAC offers reliable, licensed help that will solve your problem and get your home cool again quickly. Air conditioning is especially important in summer when we cannot leave the house. So stop cooking for yourself – if your air conditioning won’t turn on, call Tudi Mechanical Systems now!