Why Is My AC Unit Not Turning On?
An air conditioner that won’t turn on can be frustrating, especially during peak summer months in and around Cary, NC. Whether it’s a simple fix or a sign of a deeper issue, diagnosing the problem quickly is key to restoring comfort in your home.
Get help quick by calling Comfort Pro at 919-887-8889 in Wake County, NC when your AC unit doesn’t turn on when you need it!
DIY Air Conditioner Troubleshooting
We’ll give you some common reasons why your home air conditioning unit won’t start and provide step-by-step troubleshooting DIY methods to help resolve the issue.
Check the Thermostat Settings
One of the most overlooked reasons an AC won’t turn on is incorrect thermostat settings.
Ensure the following:
- The thermostat is set to ‘cool’ mode and not ‘heat’ or ‘off.’
- The temperature is set lower than the current room temperature.
- The batteries are functional (if your thermostat uses batteries).
- The thermostat display is working. If it’s blank or unresponsive, consider replacing the batteries or resetting the unit.
Inspect the Circuit Breaker & Power Supply
A tripped circuit breaker is a common culprit for an AC unit not powering on.
Here’s how to check:
- Locate your home’s electrical panel.
- Find the breaker labeled ‘HVAC’ or ‘AC.’
- If the breaker is in the ‘off’ position, switch it back to ‘on.’
- If it trips again immediately, this could indicate an electrical issue requiring professional attention.
Also, ensure the AC unit’s power switch (located near the indoor unit) is in the ‘on’ position.
Inspect the Air Filter for Clogs
A dirty air filter can cause multiple issues, including restricted airflow, overheating, and AC failure.
Follow these steps:
- Turn off the AC unit.
- Locate the air filter (typically inside the return vent or near the air handler).
- Check if the filter is dirty or clogged with dust and debris.
- If dirty, replace or clean it based on the manufacturer’s recommendations.
- Reset the system and check if the AC turns on.
Examine the Condensate Drain Line
Many AC units have a safety switch that shuts down the system if the condensate drain line is clogged. Here’s how to check:
- Locate the drain pan under the indoor unit.
- If it’s full of water, the drain line might be clogged.
- Use a wet/dry vacuum to clear any debris from the drain line.
- Reset the AC system and try turning it on again.
Test the Capacitor and Contactor
If your AC unit is unresponsive, faulty electrical components like the capacitor or contactor may be to blame.
- Capacitor Issues: A weak or failed capacitor prevents the AC compressor and fan from starting. Listen for a clicking sound or humming noise without the fan running.
- Contactor Failure: A damaged contactor won’t send power to the compressor and fan motor, causing a complete shutdown.
Professional testing and replacement of these components may be necessary.
Inspect the Outdoor Unit
The outdoor condenser unit is essential for AC operation. Ensure:
- No debris (leaves, dirt, or grass) is blocking airflow.
- The unit is receiving power (check the disconnect switch).
- The condenser coils are clean.
If the outdoor fan isn’t running, the motor or capacitor could be faulty.
Look for Refrigerant Leaks
Low refrigerant levels can prevent your AC from turning on. Symptoms of a refrigerant leak include:
- Ice buildup on refrigerant lines.
- AC blowing warm air before shutting down.
- Hissing or bubbling sounds from the unit.
A licensed HVAC technician must handle refrigerant leaks and recharging.
Reset the AC System
If none of the above steps work, try resetting the system:
- Turn off the thermostat.
- Flip the circuit breaker off for 5 minutes.
- Turn the breaker back on and wait a few minutes.
- Restart the thermostat and set it to ‘cool.’
When Should You Call a Professional HVAC Contractor?
If your AC still won’t turn on after trying these troubleshooting steps, it’s time to call Comfort Pros at 919-887-8889 .
Common signs you need expert help include:
- Repeated circuit breaker trips.
- Burning smells or electrical sparks.
- Loud banging or grinding noises.
- Complete compressor failure.
No One Wants To Feel Hot Inside When It’s 90 Degrees Outside
By following this troubleshooting guide, you can diagnose and fix some common air conditioner issues efficiently. If problems persist, seeking professional HVAC assistance ensures a reliable and long-term solution. Call Comfort Pro at 919-887-8889 for all your air conditioning repair and HVAC installation service needs. We’re available 24 hours a day.
