If you live in an area that experiences very low temperatures during the winter months, it is essential for your home's heating system to operate properly and produce warm air in order to keep the interior of your house warm and comfortable. Thus, it can be quite alarming to hear your heating system turn on but then notice that the air blowing out of the vents is cool, not warm. Luckily, if your heating system is blowing cool air instead of warm air, it doesn't automatically mean that it has failed and needs to be replaced. In many situations, issues that cause a heater to blow cool air can be replaced. Some of the most common reasons a residential heating system stops producing warm air include the following:
Faulty High-Limit Switch
A heating system is equipped with a high-limit switch that is responsible for monitoring the temperature of the system. If the high-limit switch fails, it will mistakenly sense that the heating system is getting too hot and stop producing warm air, but the blower fan may continue to run. When this happens, it will sound like your heating system is running, but actually, the blower fan is just blowing cool air. An HVAC contractor can remove the bad high-limit switch and install a new one to repair the issue.
Problems With the Ducts
In some cases, your heating system may be working properly, but issues with your ducts can result in cool air flowing through the vents instead of warm air. This can happen when you have old ducts in your home that have developed cracks, holes, or any other type of damage. When this occurs, the warm air seeps out of the ducts and the cold outside air can flow in so the air that is forced into your home will feel cool. Contact an HVAC technician to inspect your ducts if you have cool air flowing through the vents in your home.
Issues With the Flame Sensor
A flame sensor is designed to sense the presence of the flame and create a current that helps the heating system begin producing warm air. If a flame sensor is dirty or has failed completely due to age, it will no longer sense the presence of the flame so it will turn off the burner. However, the blower fan will continue running, and cool air will come out of the vents. An HVAC professional can examine your flame sensor to see if it simply needs to be cleaned or if it needs to be replaced.
Contact a company like IMS Heating & Air Inc to learn more.