HVAC Troubleshooting Steps

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.

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

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.