HVAC Troubleshooting Guide

(502) 968-6222

It’s always nice when an expert is just a phone call away. There are, however, some quick and easy solutions you can try on your own. Below is a list of common issues, causes and remedies for HVAC systems. For anything that falls outside this list, please contact us.

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Common issues, causes and remedies for HVAC systems

Not Cooling

You may have a tripped circuit breaker in your home

  • First Course of Action – Check your home circuit breaker box
  • Suggested Solution – Reset circuit breaker

Your thermostat may be off or set incorrectly

  • First Course of Action – Make sure your thermostat is on and set to cool
  • Suggested Solution – Reset thermostat to your desired temperature

Your indoor unit is running but the outdoor unit is not

  • First Course of Action – Make sure your thermostat is on and set to cool
  • Suggested Solution – Reset thermostat to your desired temperature

If the above troubleshooting steps do not assist, please call DFH for help at (502) 968-6222.

Not Heating

Check your air filter

  • First Course of Action – Check the filters in your unit
  • Suggested Solution – Clean or replace filters as recommended in your use & care manual. If the problem persists, please contact us.

Your thermostat may be off or set incorrectly

  • First Course of Action – Make sure your thermostat is on and set to heat
  • Suggested Solution – Reset thermostat to your desired temperature

You may have a tripped circuit breaker in your home

  • First Course of Action – Check your home circuit breaker box
  • Suggested Solution – Reset circuit breaker

No Airflow

Check your air filter

  • First Course of Action – Check the filters in your unit
  • Suggested Solution – Clean or replace filters as recommended in your use & care manual. If the problem persists, please contact us.

Your system may have frozen up as the result of a dirty coil

  • First Course of Action – Check for signs of water below the unit and a cold exterior surface of the indoor coil enclosure
  • Suggested Solution – Contact us. In the meantime, turn your thermostat off and the fan “on” for 1–3 hours until airflow returns to normal

Unusually High Utility Bills

Schedule a service visit

  • Suggested Solution – Contact us to set a time to get your equipment serviced.

Equipment Runs All the Time

Your system could be trying to reach a set point that is too extreme

  • First Course of Action – Check the set point on your thermostat. Is it very low (summer) or very high (winter)?
  • Suggested Solution – Adjust your thermostat. If that doesn’t work, please contact us.

Drain Pan Is Overflowing

The overflow switch is probably not working

  • First Course of Action – Turn your system off
  • Suggested Solution – Contact us

How can I troubleshoot a malfunctioning thermostat?

Check the batteries

  • Replace the batteries if the display is dark or blank.

Inspect circuit breakers

  • Ensure the circuit feeding the system hasn’t tripped.

Program correctly

  • Verify and adjust the schedule/settings as needed.

What should I do if my HVAC system is blowing warm air instead of cold?

Check thermostat settings

  • Ensure the thermostat is set to “cool,” not “heat,” and that the fan is on “auto,” not “on.”

Inspect air filters

  • Dirty or clogged filters reduce cooling efficiency and can cause warm air. Replace or clean the filters regularly.

Check refrigerant levels (pro)

  • Low refrigerant can cause warm air. If suspected, contact a professional to diagnose and address any leaks.

Why is my HVAC system making strange noises?

Rattling noise

  • Loose panels or debris can cause rattling. Inspect for obstructions and tighten any loose components.

Buzzing noise

  • Persistent buzzing from the outdoor unit may indicate a refrigerant issue or heavy usage. Turn off the AC for a few hours and check the condenser fan. If in doubt, consult an HVAC technician.

Squealing or screeching

  • Usually from worn parts or lack of motor lubrication. Regular maintenance and timely repairs help prevent failures.

What Our Customers Say

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Kurt Kennedy profile picture
Kurt Kennedy
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When our home A/C unit stopped blowing cool air during a weekend emergency—with no frozen condenser coils and a warm suction line—contacting DFH Heating and Cooling was the best decision we could have made. Our technician, Ralph, was friendly, personable, knowledgeable, and skilled. He arrived at our house within 30 minutes of our call, quickly resolved the issue, and patiently answered all of my questions regarding causation and future maintenance. If you are dealing with unexpected HVAC trouble, I highly recommend calling DFH Heating and Cooling.
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Heather Cameron profile picture
Heather Cameron
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Very attentive and honest with diagnosis. Had to have them out several times and all technicians were friendly and knowledgeable. Five stars! Thank you!
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Nathan Beachy profile picture
Nathan Beachy
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Worked to repair existing equipment without sales pressure. Technician was easy to work with and clearly experienced. Good, honest work. Will use again.
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SARAH CUNNINGHAM profile picture
SARAH CUNNINGHAM
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Wonderful service. I have used them for replacing the furnace and now the air conditioning unit. Polite, professional, personable, nice to my dogs, closed the fence before they left. I would recommend to anyone who needs HVAC services.
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Jacob Choe profile picture
Jacob Choe
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Called DFH Company originally diagnose a leak. They determined an evaporator coil needed replacement and provided a replacement estimate at what I thought was a fair price. Since the system was quite old, we then started collecting quotes. DFH's estimate was similar to other companies but offered a Trane system whereas Goodman was what the others were offering. We went forward with DFH's estimate. They came out in a few days and installed a new Trane system in one day. There was a manufacturing defect in one of the parts right out of the box, but after notifying DFH, they arrived the next day to replace it and address the issue quickly. Will recommend DFH to anyone who has property in Louisville.
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Walker Gnadinger (Peyton) profile picture
Walker Gnadinger (Peyton)
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Tommy did a great job!
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Rick Suel profile picture
Rick Suel
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Outstanding company! My 30 year old system finally bit the dust, so I called DFH to come take a look. They showed up the same day to evaluate the old system, and one day later my new Trane furnace is installed and running! They don’t look to upsell you or nickel and dime you, they just do what needs to be done, quickly, and for a fair (great!) price. I love that they are locally owned too. Will definitely use DFH going forward.

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