Common AC Problems and Troubleshooting Tips

December 2, 2025
Close-up of a light-colored air conditioning unit, with a fan on top, in an outdoor setting.

Common AC Problems and Troubleshooting Tips

When your air conditioner starts acting up just as the heat rolls in, it can quickly turn from a minor annoyance into a full-blown emergency. At Modern Heating & Plumbing Co., we’ve seen the most frequent issues homeowners encounter, and we’ve got practical advice to help you troubleshoot—and know when it’s time to call in the professionals.

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Poor or No Cooling

If your home isn’t staying cool—even when the system is running—several common culprits could be at play:


  • Dirty or clogged air filters restricting airflow
  • Refrigerant leaks or low levels impacting performance
  • Worn or malfunctioning internal parts interfering with cooling
  • Leaky or damaged ductwork reducing overall efficiency


These issues are often detected during a professional inspection, and timely repair can prevent total system failure.

Frequent Cycling or System Not Responding

If your cooling system turns on and off too frequently—or doesn’t respond at all—it may be due to:


  • Thermostat miscalibration or faults disrupting signal commands
  • Internal wear causing electrical or mechanical failures
  • Blocked vents or filters altering register airflow and pressure


Proper maintenance, including thermostat calibration and airflow checks, can restore balance and performance.

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Frozen Coils or Ice Buildup

Ice formation on your system is a clear warning that something is off. Typical signs include:


  • Visible ice on coils or refrigerant lines
  • Reduced airflow from vents, despite the system running
  • Warm air blowing out despite operation


To address a freeze-up:


  • Shut the system off to prevent damage, especially to the compressor
  • Inspect and replace dirty air filters impeding airflow
  • Adjust thermostat settings—avoid setting it excessively lower than outdoor temps
  • Clear or unblock supply and return vents to improve flow
  • Clean the condensate drain to prevent backups that could lead to freezing
  • Once thawed, resume operation cautiously and monitor closely
  • If freezing persists, schedule a professional inspection for possible refrigerant issues

Unusual Noises or Odors

Strange sounds (squealing, banging) or unexpected odors often point to:


  • Mechanical wear or loose components rattling during operation
  • Accumulated debris or mold causing funky smells
  • Electrical issues that may pose safety risks


Prompt attention can catch these problems before they escalate and help preserve both your comfort and your system’s integrity.

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Why Choose Modern Heating & Plumbing Co.?

Choosing Modern Heating & Plumbing Co. means putting your trust in a company with deep roots in the Gurnee area since 1948. Our skilled technicians combine decades of experience with state-of-the-art equipment to address every issue—from clogged filters and refrigerant leaks to frozen coils and worn parts. We prioritize rapid diagnosis, transparent recommendations, and long-term solutions tailored to your home and budget. From routine tune-ups to emergency repairs, we stand by your side, ensuring your cooling system stays efficient, reliable, and ready for whatever the season brings.

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