October 20, 2020

During cold weather, you want to be sure that your furnace is blowing plenty of hot air. But when it stops blowing hot air and starts blowing cold air, you know you have to find a solution.

Fortunately, there are specific reasons why your furnace may not be working properly and specific fixes to those causes. Use the list below to investigate the causes and what you can do to solve them.

Thermostat Set Incorrectly

Most people immediately think about the worst-case scenario when it comes to their furnace and often neglect the simple things. The thermostat is one of the simplest fixes for a furnace that’s blowing cold air. Check to make sure it is switched to “heat” and that the batteries are still good.

Also, check to see whether your fan is set to “auto” or “on.” If it is set to “on,” then it will blow all the time. When the furnace is not running, it will feel like cold air coming out, with nothing actually wrong.

It almost seems too simple, but it can fix a lot of issues.

Clogged Air Filter

Furnaces are built on the idea of circulating air. It draws air in, heats it up, then pushes it back out again. If there is an obstruction, your furnace will not work correctly. One of the first obstructions you will encounter is a clogged air filter.

When there is an obstruction, it causes the furnace to retain more heat. This will signal the furnace to shut off more quickly than it should. The fan will keep blowing for a period after the furnace shuts off to dissipate the heat. But if the furnace never reached the proper temperature, it will just circulate cold air.

Even if it does not look overly dirty, there may be a clog within the filtering material. To avoid this, be sure to change it every 30 days.

Fuel Supply Problem

Every furnace runs on some sort of fuel, whether that is kerosine, natural gas, or propane. If there is a problem with that fuel reaching its destination, then the burner will not produce the heat that it should. Any time you suspect a problem with fuel delivery, you should call a licensed HVAC professional to solve it. Attempting to fix this kind of problem on your own may result in serious physical harm to you or others.

Condensate Drain Clog

When the furnace is running, it creates some moisture known as condensation. That extra moisture has to go somewhere so that it does not damage your furnace. In newer models, there is a drain called a condensate drain. When the moisture drains, it can carry various particles with it, including dust that has built up in the system. These particulates can create a clog that will trip a sensor, preventing the burners from firing. You can attempt to clear this clog using a wet/dry shop vacuum.

Flame Sensor Malfunction

In your furnace are a number of sensors that keep it running properly. If one of these sensors malfunctions, it will prevent the unit from heating effectively. One of the sensors is the flame sensor, which tells the system if your burners are ignited. If this sensor fails, the system may think the burners are ignited when they are not, causing the furnace to blow cold air. This is one of the repairs that should only be performed by a licensed technician since the sensor is located within the combustion chamber.

Faulty Ignitor

One critical component that contributes to your furnace creating heat is the ignition system. In some furnaces, this will be what is commonly known as a pilot light. In other systems, it may be an electric component that heats up.

If your furnace has a pilot light, then check to make sure it is lit, and relight it if has gone out. Call a licensed technician to investigate if you find the pilot light is constantly blowing out.

If your furnace has a hot surface ignitor, then it could be a problem with the connection to the component, or it may be burnt out. These ignitors are typically very sensitive, so enlist the service of a licensed technician to evaluate and replace it.

Dependable Furnace Repair

When you have furnace problems, you want to know the company you call will fix it correctly the first time. Air Care Heating & Cooling has been providing heating repair and installation to the greater Kansas City area since 1981. Our team also provides air quality, duct cleaning and water heater services, allowing you to call a single company. Call to schedule a consultation with our team today.

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