HVAC Troubleshooting Steps

If you notice anything unusual about your home comfort system's performance, there are a few common things to look for before contacting your contractor.

Keep Your HVAC System Running Its Best

Follow the steps below to determine and take care of common furnace and air conditioning issues. If any issues persist, please contact your Fraser-Johnston® Contractor for service and have all related model numbers ready.

Troubleshoot Your Air Conditioner

Check your thermostat.

  • Make sure your thermostat is set in the cool position (or heat, for winter heat pump operation).
    • If it is, confirm that your outdoor air conditioner or heat pump is running.

Check your power. 

  • See if your circuit breaker has been tripped to the OFF position
  • Confirm the outdoor disconnect switch on your outdoor unit is in the ON position.
    • You can usually find the disconnect switch mounted on a wall near the outdoor unit. It's typically a small, gray metal box
  • Make sure the blower motor in your furnace or air handler is running when your thermostat is turned on
    • Check that the furnace switch is in the ON position

Check the airflow.

  • See if your air filter is dirty, and change it if it is
    • A blocked filter can cause your unit to shut down due to improper airflow
  • Make sure air registers (supply or return ducts) are clear

Troubleshoot Your Gas Furnace

Check your thermostat.

  • Make sure your thermostat is set to the heat position.
  • Confirm that the temperature setting on the thermostat is set higher than the thermostat's indoor temperature.

Check your power.

  • Make sure the power is turned on for your furnace.
    • Turn the fan to ON at your thermostat. The fan should run when power is being supplied to the furnace.
  • See if the circuit breakers in the circuit breaker box (or electrical panel) tripped to the OFF position.
    • Check the SSU light switch on the gray box located at the furnace to make sure it is in the ON position.

Check the airflow.

  • See if your air filter is dirty, and change it if it is.
    • A blocked filter can cause your unit to shut down.
  • Make sure air registers (supply or return ducts) are clear.

Speak with an Expert

Our Certified Comfort Experts are highly trained in home heating and cooling needs, and can provide you with a personalized solution that's right for your home.

Schedule a Home Consultation

Learn More

YORK® | Parts

Repair or Replace: Replacing Existing Equipment

Find out how to get replacement parts for Fraser-Johnston® residential equipment here.

YORK® | Maintenance Tips

HVAC Care

Helpful tips for inspecting your own home comfort system – including indoor air quality (IAQ) equipment, air handlers, air conditioner/heat pumps and furnaces. 

YORK® | Preservice Checklist

Pre-Service Prep

You can help your Fraser-Johnston® Certified Comfort Expert™ Contractor make maintenance visits fast and productive. Here you'll find tips on what to check and prepare before your contractor visits.