You turn your furnace on and, after a few minutes, you suddenly realize that it’s blowing cold air. It’s not a good feeling in more ways than one. Before you start imagining a high repair bill or a long cold night without heat, read through these three common reasons for your furnace blowing cold air, and the solutions!
The first place you may have checked when you felt the chill from the furnace blowing cold air was the thermostat. Make sure the thermostat is in the HEAT position. If you have a new thermostat that you’re unfamiliar with, refer to the user’s manual.
Look to see if the thermostat is in the AUTO or ON position. In AUTO mode, the blower will automatically turn on and off when the furnace is heating or is not heating. In the ON mode, the blower is going to run all of the time, whether the furnace is heating or not. So, you’ll feel airflow in the ON position, but it won’t be newly heated airflow.
Overheating will cause your furnace to shut down. However, the blower motor will continue to circulate airflow to cool down the furnace. A common reason for an overheating furnace is a clogged air filter blocking airflow. It’s best to keep a box of high-efficiency filters on hand through the heating months, and change them as the manufacturer suggests. If the filter was fine, call your HVAC technician to diagnose the problem.
Flame Goes Out
When your thermostat calls for HEAT, a thermocouple opens the gas valve. The gas is ignited by a standing pilot light or an electronic igniter system.
- A pilot light that won’t stay lit may be caused by a nearby draft, or the orifice is dirty.
- A dirty flame sensor is another reason why a furnace won’t stay lit and blows cold air. Refer to your user’s manual for cleaning instructions. However, it’s best to call a professional.
If you’re still having problems with your furnace blowing cold air in your Grand Traverse County home, contact Team Bob’s Heating Cooling Plumbing.
Our goal is to help educate our customers in Traverse City, Michigan and surrounding areas about energy and home comfort issues (specific to HVAC systems). For more information about furnace problems and other HVAC topics, download our free Home Comfort Guide or call us at 231-714-6196.
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