Common AC Problems:  Tips to Troubleshoot & When to Call a Professional HVAC Technician

As summer temperatures climb, your air conditioner becomes one of the most essential systems in your home. But when it starts acting up: blowing warm air, making strange noises, or failing to turn on altogether, it can quickly turn a comfortable day into a stressful one. 

Fortunately, many common AC problems can be identified with a few simple troubleshooting steps. Knowing what you can fix on your own, and when to call a professional HVAC technician, can save you time, money, and discomfort.

1. Your AC Isn’t Turning On

DIY Troubleshooting Tips:

• Check the thermostat: This might sound basic, but a lot of AC problems start with the thermostat. Ensure it’s set to “cool” and the temperature is lower than the room temperature.
• Replace the batteries: If your thermostat runs on batteries, try swapping them out. A weak or dead battery can prevent the AC from kicking on.
• Check the breaker box: A tripped circuit breaker is another common cause. Reset the breaker if necessary.
• When to call a pro: If the thermostat is working, the breaker hasn’t tripped, and the unit still won’t start, the issue could be with the compressor, capacitor, or internal wiring. These are not safe for DIY repair and should be diagnosed by a licensed HVAC technician.

2. Warm Air Instead of Cool Air

DIY Troubleshooting Tips:

• Replace the air filter: A clogged or dirty air filter restricts airflow and can cause your system to overheat or circulate warm air.
• Clear vents and registers: Make sure furniture or curtains aren’t blocking airflow around your home.
• Check the outdoor unit: Debris like leaves or grass clippings around the outdoor condenser unit can obstruct airflow. Gently clean around it.
• When to call a pro: If your filter is clean, vents are open, and the system is still blowing warm air, you may have a refrigerant leak or a failing compressor—both of which require professional attention.

3. Strange Noises Coming from the Unit

DIY Troubleshooting Tips:

• Rattling or vibration: Sometimes, loose panels or screws can cause rattling. Turn off the unit and check for loose parts you can safely tighten.
• Humming: A low hum may be normal, but an unusually loud humming noise could indicate electrical issues or a failing capacitor.
• When to call a pro: Persistent banging, screeching, or grinding sounds could be signs of a motor failure, broken fan blade, or internal damage. Avoid running the system and schedule a technician visit immediately to prevent further damage.

4. AC Running Constantly or Short Cycling

DIY Troubleshooting Tips:

• Adjust the thermostat settings: Sometimes, a low temperature setting or fan set to “on” instead of “auto” can cause continuous running.
• Inspect the air filter: Again, a clogged filter can cause inefficiency, leading to longer or shorter cycles.
• When to call a pro: Short cycling (frequent starting and stopping) or running non-stop may indicate a refrigerant problem, sensor issue, or oversized system—all of which require professional diagnostics and repair.

5. Uneven Cooling in Different Rooms

DIY Troubleshooting Tips:

• Check air vents: Ensure all vents are open and unobstructed.
• Seal windows and doors: Drafts can affect how efficiently your system cools certain rooms.
• Inspect ductwork (if accessible): Look for visible leaks or disconnected ducts in accessible areas like attics or basements.
• When to call a pro: If airflow remains inconsistent after these checks, there may be a blockage or leak in your ductwork, or your system may need to be rebalanced. A technician can assess airflow and make necessary adjustments.

Contact Snellville Heating, Air and Plumbing, where your comfort is OUR business.