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Heating & Cooling Services

Air Conditioning Troubleshooting Guide

Need help troubleshooting your air conditioning system? At Modern Sheet Metal, our A/C technicians have years of experience guiding our customers with the proper troubleshooting and maintenance that comes with owning an A/C unit.

Air conditioning is essential to keeping your home cool and comfortable during Wisconsin’s hotter summer months. From the months of June-September it can get pretty hot.

Read More: 10 Air Conditioning Myths That are Costing You Money

Air Conditioning Troubleshooting Tips to Follow

When your AC breaks down, simply popping open a window or running a fan isn’t enough on a particularly hot summer day.

The good news is that there are several instances where it is just a simple fix. While you may need an air conditioning maintenance service, below are some troubleshooting tips and solutions so you can get your AC back up and running:

Thermostat Issues

Air Conditioning Troubleshooting - Thermostat

If your air conditioning system is experiencing troubles, the first thing to rule out as an issue is your thermostat. First, make sure that you have set the thermostat properly. Keep in mind is to occasionally check the thermostat batteries to make sure to rule dead batteries as a reason why your thermostat and A/C unit aren’t working properly.

Air Conditioning Troubleshooting Steps:

  1. Check Settings:
    • Ensure the thermostat is set to “cool” and the temperature setting is lower than the current room temperature.
  2. Power Source:
    • Verify that the thermostat’s power source (batteries or electrical connection) is functioning.
  3. Calibration:
    • Thermostats can become miscalibrated. Consider recalibrating or replacing an old thermostat.
  4. Wiring Issues:
    • Loose or corroded wires can cause issues. Inspect the wiring, but consider hiring a professional for repairs.

Preventative measures to take with your thermostat include regularly checking and replacing the batteries, and also cleaning and dusting the thermostat to ensure good sensor function.

Note: A smart or programmable thermostat may make sense for you if you are interested in investing in setting your A/C automatically at certain settings throughout the day while at work and at home.

High Energy Bills

High Energy Bills - A/C Troubleshooting

High energy bill can also be a symptom of inefficient AC operation. If you’re experiencing higher energy bills than normal, this may stem from either a lack of maintenance or an aging system.

A/C Troubleshooting Steps:

Regular Maintenance:

  • Check and replace air filters every 1-3 months.
  • Ensure outdoor unit is free from debris and obstructions.

System Inspection:

  • Have a professional inspect the ductwork for leaks and insulation issues.
  • Ensure the thermostat is functioning correctly.

Upgrade Considerations:

  • If the A/C unit is old, consider upgrading to a more energy-efficient model.
  • Look for ENERGY STAR-rated models for better efficiency.

If you have any questions about the maintenance of your air conditioning system or think you may need to upgrade, please contact our technicians today!

Limited Airflow from Vents

Limited Airflow from Vents - Air Conditioning Troubleshooting

Another air conditioning issue that may come up from time to time is limited airflow from the system’s vents. Overall, restricted airflow can impact the overall efficiency and effectiveness of your AC.

Air Conditioning Troubleshooting Steps:

  1. Filter Check:
    • Replace or clean air filters, as a clogged filter can restrict airflow. If they get clogged by dust, dirt, or bugs, the air can’t flow properly; simply cleaning your air vents could be the answer to your problems.
  2. Duct Inspection:
    • Check for blockages or leaks in the ductwork.
    • Consider professional cleaning if ducts are dirty.
  3. AC Unit Check:
    • Ensure the outdoor unit is not obstructed.
    • Check for frozen coils which can restrict airflow.

If you are unable to perform any of the steps above, please contact our technicians for assistance with checking your filters, ducts, coils, and overall unit. We are here to help!

Circuit Breaker Issues

Issues with Circuit Breakers

Your air conditioning unit may not be functioning due to an issue with the circuit breaker. The breaker protects your home’s electrical circuit from damage due to overloading or short circuiting. Tripping may indicate issues with the AC unit or the electrical system.

A/C Troubleshooting Steps:

  1. Reset the Breaker:
    • Turn off the AC. Reset the circuit breaker by turning it off and then on.
  2. Inspect AC Unit:
    • Check if the AC unit shows signs of short-circuiting, such as a burnt smell or visible damage.
  3. Electrical Load:
    • Ensure that the AC unit is not overloading the circuit. Consider if other high-energy appliances are sharing the circuit.
  4. Professional Inspection:
    • Persistent tripping requires professional inspection of both the electrical system and the AC unit.

Preventative measures to take with your circuit breaker include: ensuring that your air conditioning system is on a dedicated circuit (ask your technician about this if you’re unsure.) Also, be sure to regularly maintain your unit to prevent the possibility of a tripped circuit.

Ice on Refrigerant Lines

Ice on Refrigerant Lines

Another air conditioning troubleshooting issue is when ice forms on the refrigerant lines. If you’ve ruled out the above issues, you may want to assess your filters and airflow for any possible blockage and leaking. Here are some troubleshooting steps to follow:

Air Conditioning Troubleshooting Steps:

  1. Turn Off the AC:
    • Immediately turn off the AC to prevent further damage.
  2. Inspect Airflow:
    • Check filters and airflow for obstructions.
  3. Professional Help:
    • Refrigerant issues often require professional assistance.
    • A technician can check refrigerant levels and inspect for leaks.

Follow the steps above to troubleshoot your air conditioning system, or contact us for assistance.

Water Leaking from AC Unit

Water Leaking from A/C Unit

Another factor to troubleshooting your air conditioning is to check for any water leaking from the unit. Water leaks in your A/C can lead to issues with condensation and drainage:

A/C Troubleshooting Steps:

  1. Inspect Drain Pan and Line:
    • Check for clogs or damage in the drain pan and line.
  2. Check Air Filters:
    • Dirty filters can cause ice formation and subsequent melting.
  3. Review Installation:
    • Incorrect installation can lead to improper drainage.
  4. Professional Inspection:
    • Persistent leaks should be examined by a professional.

Following your DIY inspection of the drain pan/line, air filters, or any clogging, if you’re still coming up short, please contact Modern Sheet Metal and we can help.

Related: Signs You Need a New Air Conditioning Unit

Poor Cooling Overall

A/C Poorly Cooling Home

In general, is your air conditioning just not effectively cooling your home? There are various factors involved to your A/C not cooling your home properly:

Air Conditioning Troubleshooting Steps:

  1. Thermostat Settings:
    • As mentioned earlier, you’ll want to ensure your thermostat is set correctly and functioning.
  2. Check for Obstructions:
    • Clear any obstructions around vents and outdoor unit.
  3. System Maintenance:
    • Regular maintenance, including filter changes and coil cleaning.
  4. Seek Professional Help:
    • Persistent issues may require a professional assessment.

Read More: The Differences Between a Heat Pump and Central A/C

When to Contact an HVAC Professional

While there are plenty of things you can do on your own to combat common problems with your air conditioner, (more info on 10 things to check before calling an HVAC technician here), there are several instances where you need to contact a professional.

We indicated above when you’ll need to get a professional involved, but here are also some additional signs to look out for:

  • Strange noises coming from your AC: Is your air conditioner making loud banging, clanging, or other unfamiliar noises? If these sounds are coming from your air conditioner or vents, you likely have a problem on your hands. Contact an HVAC professional will understand the issue and find a solution. 
  • Issues with the outdoor unit: If your outdoor air conditioner unit is the problem, you should not try to fix this yourself. While changing your air filters and replacing batteries is perfectly fine for you to do on your own, fixing more complicated issues may void your warranty. For true maintenance issues, it’s best to contact a professional.
  • Improperly installed AC: If you’ve noticed that your air conditioner was not installed properly, you should call a professional to reinstall or fix it. 

Here are some additional air conditioning maintenance tips to follow.

Contact Modern HVAC for Air Conditioning Troubleshooting Today!

Having issues that require a professional? If you’re having a hard time with the air conditioning troubleshooting process, Modern HVAC offers many air conditioning services. Our heating and cooling experts are always here to help answer any of your questions. We are Carrier certified experts who are skilled in understanding and troubleshooting proper airflow, vents, leaking, circuit breaker issues, thermostat problems, and more.

Whether you need an A/C installation or A/C replacement, our experts can walk you through your best options. Contact us today to get started. Our team is based in Neenah, and we serve the Fox Valley: this includes Appleton, Menasha, Kimberly, Greenville, and Darboy.

Need air conditioning troubleshooting assistance? Schedule a service with us today!


Modern Sheet Metal provides furnace and air conditioner service, repair, replacement and installation throughout Appleton, Neenah, Menasha, Darboy, Kimberly, Kaukauna and Greenville. Please call us at 920-733-4713 to discuss your residential or commercial heating & cooling needs!