Why Is My Furnace Blowing Cold Air?

February 11, 2021

There is nothing more comforting than coming back to a warm house after a long winter day at work or in school. On the other hand, when you are expecting to enjoy a warm home, it can be frustrating to find that your furnace is blowing cold air. The heating unit in your home may be temperamental, and sometimes furnaces just break down regardless of their age. Here are some of the possible reasons why your furnace is blowing out cold air.

Incorrect Thermostat Setting

An incorrect thermostat setting can cause a furnace to behave this way. If you have the fan set to “ON” rather than “AUTO,” the furnace will continually blow out air that hasn’t been heated. You can solve this issue by setting your thermostat correctly or consulting a technician if the device is faulty. Another issue with your thermostat that can cause your furnace to misbehave is the battery. Not all furnaces are connected to the central power in the home. Some require a battery pack to operate. If the batteries are low, that might impact the effectiveness of the furnace.

Dirty Filter

If the last time you cleaned your filters was several months ago, that could be the reason behind your furnace blowing cold air. Dirty filters affect the functionality of a furnace by restricting airflow. If changing air filters doesn’t resolve the issue, you should have a qualified technician check out your furnace.

Furnace Hasn’t Warmed Up Yet

If you had turned off your furnace for a while, it could take a while before warming up the air. Therefore, the unit might blow cold air for a few minutes after being turned on, but it will eventually warm up. If the condition persists, it’s time to call in a technician to resolve the situation.

A Dirty Flame Sensor

The flame sensor is one of a furnace’s vital safety devices. It tests to confirm whether the burners are lit. If it detects that they are not, the flame sensor shuts them off. These sensors become dirty over time, usually when the system has a clogged filter, and that can cause them to turn off the burners when they shouldn’t. When the flame sensor turns off those burners, the furnace doesn’t have a heat source. You can ensure that your furnace blows out hot air by hiring a professional to clean a dirty flame sensor. It is wise to include this task on your annual furnace maintenance schedule.

Pilot Light Is Out

Older furnaces have a pilot light that contains a device known as a thermocouple. This device determines whether the pilot light is on or off, and it shuts off the gas to the furnace’s burners when the pilot light goes out. If that occurs during a heating cycle, the fan might continue running even when the burners are off, causing your furnace to blow cold air. Contact a qualified technician to inspect the pilot light and thermocouple for any faults.

Fuel Source Issues

Furnaces use natural gas, electricity or oil as a fuel source. If your furnace doesn’t have access to fuel, it will not produce heat, causing it to blow cold air. For instance, if a furnace that uses oil for operation starts to blowing cold, check if there is enough oil in the tank. If there isn’t sufficient oil, the burner will not light, and the unit will circulate cold air.

It Overheated

Furnaces have safety features that turn off the burners when the unit starts to overheat. Cold air coming from your air vents could be due to an overheated furnace in which the safety features have turned off the burners but the blower keeps putting out cool air. This issue often occurs when the air filters are clogged. Sufficient air fails to go through them, and the furnace takes longer to warm the house. Unfortunately, running for too long can cause the furnace to overheat. If you are uncomfortable performing this task yourself, it would pay to hire a professional to clean or replace the filters.

Leave It to the Furnace Experts

These are some of the reasons why you are not getting warm air from your furnace. If a basic check doesn’t solve the problem, call Ken Parker Service, Inc. in Greenville today. Our experts will diagnose the issue for you. They have years of experience with furnace and AC repair, maintenance and installation. Our crew also tackles indoor air quality issues.

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