Why Is My Furnace Not Heating?

Have you noticed your furnace not blowing heat after you’ve upped the temperature? If your thermostat says the heat is on, but the furnace is not running, then there could be an underlying issue. With the many working components of your furnace, it can be difficult to pinpoint the exact issue.

First, try some simple troubleshooting just in case it’s an easy fix. Otherwise, it might be time to call in a professional for furnace repair or replacement.

Check the Thermostat

A common mistake with thermostat settings can often be misread as a problem with your furnace. First, if you notice the furnace is running but not blowing heat, check to ensure that the thermostat is set to heat instead of cool. It may seem simple, but this step seems so obvious that it often gets overlooked. 

Next, check to see if the fan is turned ON or on AUTO. A fan that is turned on will run constantly, heat or not, as it’s just the blower motor. You want your fan set to auto to ensure that the motor is only running when a heating cycle happens. Otherwise, the motor will push cold air since the heat isn’t running and will consistently use more energy, causing a higher utility bill.

Lastly, if your furnace is still not kicking on for heat, set the thermostat a few degrees higher than the current room temperature. This action should trigger the furnace to start a heating cycle and maintain a cozy temperature.

After following these troubleshooting steps and ensuring that your thermostat is set to the setting and temperature that you want it, and the furnace is still not blowing heat, consider contacting a professional.

Inspect the Air Filter

A dirty or clogged air filter can cause airflow problems within the furnace or ductwork of your home, preventing heat from efficiently moving throughout the unit and being dispersed into your living area. The furnace being on but not blowing heat can also be a result of an obstruction.

First, inspect the furnace filter and replace it if it is covered in dust and contaminants. It’s important to mention that the furnace filter should be changed on a regular basis, every couple of months at the very least, and more often for homes housing individuals with asthma or allergies. 

Check for Blocked Vents

Blocked or closed vents are a common factor in causing it to feel like the furnace isn’t heating the entire house. Ensure all vents aren’t being blocked by furniture and that they’re open. If the levers are stuck closed, try removing the vent cover and cleaning it. If it’s really jammed, replacement might be necessary.

If you notice a specific problem vent that’s getting less airflow than the others, inspect the inside to ensure no items have fallen or gotten trapped in the vent that could cause an obstruction.

Inspect the Blower Motor

The blower motor is a crucial component in the heating process. It’s responsible for circulating the heated air throughout your home to maintain a comfortable temperature. If the blower motor is no longer running, there may be an issue with the motor, capacitor, or control board.

Unfortunately, a broken blower motor, capacitor, or control board is a more complicated fix than just adjusting settings on your thermostat or furnace. This job requires professionals.

Examine the Fuel or Ignition

If your furnace is on and not blowing heat, there could be a problem with the fuel supply or ignition system. If something is preventing your furnace from receiving gas, then there is no fuel to combust, thus creating no heat. 

First, ensure that the gas valve is open. If your furnace requires liquid propane or oil, check the tank to determine if there is enough fuel. For natural gas furnaces, it’s wise to communicate with your utility provider to ensure that there have been no interruptions in service. 

Additionally, if the furnace’s ignition system malfunctions, gas will not combust to create heat. For older furnaces that use a pilot light, check to ensure that the pilot is not out. If so, you may need to relight it. It’s always safer to read the furnace’s owner’s manual first before taking action yourself, just in case your furnace has specific requirements or instructions. 

Lastly, if your furnace is electrically run and has an ignition system, the metal strip of the igniter switch may be dirty. This piece is extremely fragile, so gently clean it off when necessary. 

If you’ve tried all of these solutions and your furnace is still not blowing heat, then it’s time to call in an HVAC professional. At Total Comfort, we are committed to keeping you and your family warm during the brutal winters. Contact us today to schedule an appointment for our furnace services in St. Paul or Minneapolis, Minnesota.