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Cold Indoors

Why is My Heater Blowing Cold Air?

Your heating system is blowing cold air. It's starting to feel as cold inside as it is outside. If your furnace is blowing cold air, you could have one of several HVAC problems:

The Thermostat Isn't Set to the Right Temperature

Someone in the house may have adjusted the thermostat. Take a moment to check it. Make sure it's set for heating, not cooling. Verify the thermostat is set to the desired temperature. You wouldn't believe the number of HVAC calls we get where the only problem was a thermostat not set properly.

The Blower Fan Isn't Set Properly

While you're at the thermostat, make sure the fan setting is turned to "auto". If it's set to "off," the hot air from the furnace isn't getting distributed throughout the house. If it's turned to "on," the fan will run continuously, even when the furnace turns off after heating the house to the desired temperature.

The Furnace Filter Is Clogged

Your furnace has an air filter that helps keep dust out of the inside of the system. If the air filter gets clogged, it can be difficult to draw enough air into the furnace to warm the house. The air coming out of the vents can feel luke-warm due to this lack of airflow. Check your air filter before calling for service. A clean air filter could be an easy, cheap fix.

The Pilot Light Is Out

Older furnaces have a continuously burning pilot light that ignites the gas when the furnace turns on. If the pilot light goes out, the furnace won't heat up. When you have easy access to the pilot light, follow the instructions in your user's manual to light it. If it won't stay on or it's difficult to get to, call for an HVAC professional to take a look.

The Flame Sensor Is Dirty

When your gas furnace turns on, the flame sensor sends out a current to detect if there's heat coming from the flame. If it cannot detect heat within 10 seconds, it turns the furnace off. Its purpose is to prevent the build-up of gas when there's an issue with the furnace burner igniting. It will try up to three times before locking out the system.

A quick way to determine if the flame sensor is problem is to turn the system off, then back on. If you feel hot air for a couple of seconds, followed by cold air, you may have a dirty flame sensor. Call for an HVAC professional to clean it.

Contact the HVAC professionals at Robert Bair Plumbing Heating and Air immediately when you have heating or cooling problems. Our expert technicians can help identify and assist on any HVAC needs.
 

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