It's been quite a chilly winter so far in Thornton, Colorado, and now is your furnace blowing cold air? What could be wrong with your furnace? Call an HVAC professional to find out...but in the meantime read our tips on how to quickly diagnose the problem.

Troubleshoot a Cold Air Blowing out of Your Furnace

  1. Check the furnace’s air filter: a dirty filter can oftentimes be the issue with a cold air blowing out of your furnace. A dirty air filter blocks airflow over the furnace’s heat exchanger, causing it to overheat. When overheating, your furnace can trip a high limit switch, causing the furnace burners to shut off so that the heat exchanger does not crack.
  2. Check your thermostat: check out the thermostat settings and see if your fan has been switched to on. The on setting will cause the fan to blow 24/7 which would account for the cold air blowing. Switching the fan to auto should fix the issue.
  3. Check the furnaces pilot light:  The pilot light on your furnace could have gone out. There are several reasons why and how the pilot light could have gone out. The wind could have blown it out or it could be dirty. Contact a professional to clean the pilot light. Follow the tips to relight your pilot:
    1. Turn off your furnace: Turn your thermostat from HEAT to OFF.
    2. Find the furnace’s pilot light assembly and reset switch: Turn the knob to "off" and wait 3-5 minutes
    3. Turn the knob to "pilot" and press down the knob: Now you’re re-starting the flow of gas to the pilot.
    4. As you press the knob, hold a lighter to the pilot opening until the flame lights. When the flame lights, it should be a steady blue cone that hits the middle of the thermocouple (a small copper bar).
    5. Turn the knob to “on”: Your furnace should ignite.
    6. Turn the furnace on at the thermostat
    7. If the pilot won't light. Call a professional