Common Furnace Problems: Causes and Solutions

If you’re experiencing furnace problems, you’re not alone. In fact, many homeowners face similar issues with their furnaces every winter.

In this guide, we will discuss some of the most common furnace problems, as well as their causes. We will also provide solutions to help you get your furnace back up and running in no time.

What are the 7 Most Common Furnace Problems?

Here are the eight most common furnace problems and their causes:

1. Faulty igniter

The igniter is responsible for igniting the fuel in the furnace. If it fails to do so, the furnace will not work and will not blow air. This is a common problem and can be caused by a number of things, such as:

Solution:

If you think the igniter is at fault, you can try cleaning it or replacing it. If that doesn’t work, you may need to have the furnace maintained or repaired.

2. Faulty thermostat

The thermostat tells the furnace when to turn on and off. If it fails to do so, the furnace will continue to run, even when the home is not cold. This can lead to high energy bills and an overheated home.

Solution:

Check to make sure the thermostat is in good working order. If it is not, replace it.

3. Dirty filter

A dirty filter restricts airflow and makes the furnace work harder than it should, which can lead to problems. The furnace will also work less efficiently, costing you more money in the long run.

Solutions:

Replace the filter as needed, typically every month or two. You need furnace maintenance to clean the filter.

4. Clogged air vents

The most common furnace problem is a clogged air vent. This can be caused by anything from dust and dirt, to animals and insects. If your furnace is not getting enough air, it will not be able to generate heat properly. A clogged air vent will also cause the furnace to work harder, which can lead to early failure.

Solution:

The best way to prevent a clogged air vent is to regularly clean the vents and surrounding area. You can also install a screen over the vents to keep out debris. If you already have a clogged air vent, you can try using a vacuum cleaner or air compressor to clear it and the air filter. Be sure to turn off the furnace before doing this.

5. Weak or oddly colored, flickering pilot light

If your furnace’s light is flickering, weak, or has an oddly colored flame, it could be a sign that there’s something wrong with the gas valve. The pilot light is important because it is responsible for starting up the furnace burner. If it’s not working correctly, the furnace won’t be able to generate heat.

Solution:

There are a few things you can do to troubleshoot a pilot light that’s acting up:

Check to see if the gas valve is turned on all the way.
Make sure there isn't anything blocking the pilot light from shining.
If the light is flickering, you might need to clean the thermocouple.
If the flame is yellow or orange, there might be something wrong with the air intake.

If you’ve tried all of these proposed solutions, and your light is still having problems, then it’s time to call in a professional or furnace repair technician.

6. Frayed blower belt or malfunctioning

If your furnace is making strange noises, it’s possible that the blower is malfunctioning or frayed. Blower belt problems can cause the furnace to overheat, resulting in a shutdown.

Solution:

To fix a frayed or malfunctioning blower belt, you’ll need to replace the belt. To do this, you’ll first need to locate the belt and identify which one it is. The belt is usually located on the side of the furnace opposite the motor.

Once you’ve identified the belt, use a screwdriver to loosen the belt tensioner and remove the belt. Replace the belt with a new one, making sure to route it around the pulleys correctly. Then, tighten the belt tensioner, and test the furnace.

7. Cracked heat exchanger

If the heat exchanger is cracked, it can cause the furnace to leak carbon monoxide. This gas is deadly, and can cause poisoning and death.

Solution:

If you think your furnace has a cracked heat exchanger, call in a professional immediately. Do not try to fix the problem yourself. A cracked heat exchanger can be very dangerous.

If you don’t have a furnace and instead have a boiler, here you can learn about a boiler heating system.

Frequently Asked Questions

What fails in a gas furnace?

The most common failures in a gas furnace problem are dirty filters, clogged air vents, and frayed or malfunctioning blower belts. These problems can cause the furnace to overheat, work less efficiently, and make strange noises.

How do I troubleshoot my heating system?

To troubleshoot your heating system, you can check to see if the thermostat is in good working order. You can also replace the filter, clean the air vents, and/or replace the blower belt and the heat exchanger, which is the part of the furnace that actually heats the air. If this fails, you’ll need to replace the entire furnace.

Should I check my circuit breaker before calling a technician?

It’s always a good idea to check the circuit breaker before calling in a technician. If the breaker is tripped, it could be a sign that there’s something wrong with the furnace.

Is a furnace used for air conditioning?

A furnace is not used for air conditioning. An AC unit is used for cooling, while a furnace is used for heating.

Is a faulty limit control switch an emergency?

If the limit control switch is faulty, it can cause the furnace to overheat. If this happens, the furnace will shut down, and you’ll need to replace the limit control switch. While this is not an emergency, it’s still a problem that should be fixed as soon as possible.

When it comes to furnace problems, there are a few key things you can do to help troubleshoot them. If you’re not sure what’s wrong, don’t hesitate to call in a professional. They will be able to help diagnose the problem and fix it quickly and efficiently.