During winter, nothing sounds better than turning on your furnace, relaxing on your comfy couch, and spending time with your family in your well-heated home. The last thing you want is the furnace to start blowing cold air.
When the furnace first starts after a long time, it goes through a short warm-up phase, so there is a delay until the blower turns on. The furnace hasn’t run for a while, so the ductwork is also full of air. You will begin to feel warm only after all the cold air has been purged out. If your furnace is blowing cold air even after the initial warm-up phase, there could be several issues causing it.
If your furnace is blowing cold air, here is a list of possible reasons behind it
Incorrect settings
The most common reason why your furnace is blowing cold air is an incorrect thermostat fan setting. The fan should be set to “On.” When the fan is set to on, it will blow air continuously even if the furnace is not producing heat. In case the furnace always blows air, sometimes cold and sometimes hot, then it could be a fan setting issue. This happens only in the case of old thermostats with a fan control switch. Change the fan setting to “auto” to see if it solves the problem.
Dirty air filters
A clogged air filter obstructs the flow of air and results in an insufficient supply of air to heat. When the airflow is restricted, it can also lead to a temperature increase inside the furnace, which in turn can force the limit switch to stop the heating cycle. So, it is important to replace the air filters at regular intervals based on the manufacturer’s instructions and other factors such as the type of filter, time of the year, whether or not you have pets at home, and more.
Gas line supply issues
A furnace might blow cold air if there is a problem with the gas line. For example, if the gas level is low, the furnace would not be able to produce enough heat. It can also happen if the gas valve is faulty. A blockage in the gas line can prevent the gas from reaching the furnace. The heater might also blow cold air if the gas supply has been turned off for some reason.
Leaky ductwork
About 20 to 30 percent of the air that moves through the duct system is lost due to holes, leaks, and poorly connected ducts. This can result in cold air from unheated spaces to enter the ductwork, which reduces the heating efficiency throughout your home.
Flame sensor or pilot light
Older furnaces have a pilot light or a small flame that ignites the larger burners. If debris clogs the pilot light shaft, it will limit the furnace’s heat output. Check the pilot light and see if the flame is yellow instead of blue. If yes, it is a sign of blockage. In newer furnaces, there are no pilot lights. They have flame sensors that help carry out the heating cycle. If these sensors get dirty, they can cause the furnace to blow cold air.
Reach out to us if your furnace is blowing cold air
If your furnace is blowing cold air, it’s important to address the issue promptly. Please reach out to our experienced team to schedule a service visit at your convenience. During our visit, we will conduct a comprehensive inspection of your furnace to identify the underlying cause of the problem.
Our skilled technicians will evaluate various components, check for any potential blockages, and assess the overall functionality of the system.
Once we pinpoint the issue, we will provide you with a detailed explanation and outline the necessary repairs to restore your furnace to optimal working condition. Your comfort and satisfaction are our top priorities!