As the colder fall weather makes its way back, it’s likely that you’re going to be turning your furnace back on to keep your family warm. While most of the time, your furnace will run without a problem, there are times when it may have an issue. By understanding the most common issues that homeowners experience with their furnaces, you can better identify the issue and get it fixed quickly.

Dirty Filter

The most common issue that you’re likely to experience with your furnace is a dirty filter. Your heating system has a filter that works to remove unwanted pollutants from the air inside of your home. As it traps these pollutants, it will begin to fill up and restrict the natural flow of air through the filter.

It’s highly recommended that you switch out your filter every couple of months. Whenever your filter is dirty, it reduces the overall efficiency of your heating system. Not only could this end up leading to damage to your system, but it will also prematurely wear out your heating system’s components.

Pilot Light Malfunction

In order for your furnace to effectively work to heat your home, it utilizes a small flame called a pilot light. This pilot light should be blue in color and on while you’re heating system is operating. It’s not uncommon for a pilot light to go out for a number of different reasons, including a draft of air. In most cases, you can simply relight the pilot light, and your system will go back to functioning like normal.

Unfortunately, sometimes there could be another underlying issue. Whenever you notice that your pilot light is weak, flickering, or an odd color, it’s time to call in a professional. There could be a number of different reasons for these malfunctions, including excessive carbon monoxide in your gas furnace.

Cracked Heat Exchanger

An extremely important component of your heating system is the heat exchanger. This is the part of your furnace that separates the air circulating throughout your home from the combustible process of your furnace. Whenever you forget to change out your air filter or you try to overheat your home, your heat exchanger can actually crack.

When a crack is present, it can lead to dangerously high levels of carbon monoxide in your home. If you believe that you have a crack in your heat exchanger, you need to call in a furnace expert right away.

Frayed Blower Belt

In order for your heating system to move air throughout your home, it uses a blower. This blower motor is connected to a belt that allows the fan to run and circulate air. Over time, your blower belt can start to fray and eventually break. The most common warning sign of a frayed motor belt is a high-pitch squealing sound coming from your furnace. It’s best to replace this belt as soon as possible so that the efficiency and performance of your heating system are not compromised for too long.


One issue that you may notice with your furnace is short-cycling. This is described as hearing your furnace constantly kick on after it just finishes cycling. When your furnace short-cycles, it can be due to a couple of different issues, including improper airflow, a clogged filter, and even having your thermostat set too low. Identifying the source of the short-cycling is a necessity to help get your furnace back to operating at an energy-efficient level.

Faulty Thermostat

Your thermostat is the remote for your entire air conditioning system. Whenever it has a malfunction, it can affect how and if your furnace runs. If you noticed that your thermostat is not displaying any information or its temperature reading is way off from the actual temperature in your home, it’s likely that you’ll need to replace your thermostat or its batteries. In addition, if your heating system continually runs even though your thermostat is saying that your home is at your desired temperature, it could be that your thermostat is faulty and needs to be replaced.

Worn-Out Ball Bearings

The motor that works to power the various components of your furnace has ball bearings that allow it to run. Over time, these ball bearings naturally wear out and start to create a scraping sound when your heating system is running. If you hear this scraping sound, it’s important for you to shut your furnace off immediately and contact a repair expert to fix the issue.

Rattling Noises

When your heating system is operating optimally, you should only be hearing a very low running noise. If you start to hear a rattling or banging noise coming from your system, it’s an indication that there’s something wrong. In most cases, the source of the problem is going to be a loose part inside of your heating unit. It’s best to turn it off and contact a professional to fix the issue before it gets worse and costlier to fix.

Tripped Safety Switch

Most newer furnaces are constructed with a safety switch on the furnace door. Anytime the furnace door is opened, it trips the safety switch, which prevents the fan and the burner from coming on. If you notice that your furnace is not turning on, you should check to see if the furnace door is closed properly. In many cases, simply pushing the furnace door completely closed will allow the safety switch to disengage and let your furnace kick on.

No Fuel

If your thermostat seems to be working correctly but your furnace isn’t kicking on to heat your home, it could simply be due to the fact that there’s no fuel in the system. If your furnace runs on gas or propane, it’s best to check your fuel tank to see if there’s any fuel left in it. In many cases when your furnace is not running, you’ll notice that you’re completely out of fuel. After getting more fuel, your system will kick back on and work correctly.

Cold Rooms

Your furnace should function to heat all the rooms in your home to the same temperature. Whenever there is an obstruction in your ductwork, it can prevent certain rooms of your home from getting the heat that they need. If you notice that one or more of your rooms feels much colder than the other ones in your home, it’s best to check your ductwork.

In many cases, the culprit for uneven air distribution is an object that was placed in front of the vents for that particular room. The object may be a piece of furniture, a plant, or something else that you accidentally placed in front of the vent. After removing the object, you’ll notice that heat will blow out of the vents, and the room will start to heat back up.

Trustworthy Furnace Repair Service

Triple A Air Conditioning & Heating is a trustworthy furnace repair specialist with offices in Flower Mound and Irving. We also provide furnace installations and maintenance and offer assistance with indoor air quality and cooling systems. Simply call us today to schedule your next appointment!

company icon