Common Furnace Problems

When it comes to furnaces, most homeowners don’t think too much about them until they start to notice issues when the cold weather strikes.

However, the older your furnace gets, the more likely it will need repairs or start to malfunction.

To help you if an issue arises with your furnace, we’ve compiled a list of the most common furnace problems and how to fix them. The problems include:

• A furnace that’s blowing cold air
• Your furnace won’t turn on
• Strange noises coming from your furnace

In this blog, we’ll go over these issues in detail and how they can be solved. While many problems are minor and can be fixed quickly without professional help, other issues may be more serious and will require you to call in the pros for a repair or replacement.

There are many reasons why your furnace could be blowing cold air including the wrong thermostat setting, clogged or dirty air filters, a faulty or broken fan switch –or something else entirely. Before you call the pros, we recommend doing the following:

1. Check your thermostat. Before you do anything, make sure your thermostat is set to the proper settings. Make sure your thermostat FAN is set to AUTO and not ON. If your thermostat is set to ON, that means the air will blow all the time, even when your furnace is not producing heat. You also need to make sure that it’s set to HEAT and not COOL. While this sounds obvious, it’s not uncommon for settings to be changed accidentally.
2. Check your air filter. If your air filter is clogged or filthy, it will block the flow of air to your heat exchanger. If the heat exchanger isn’t getting proper airflow, it can overheat and trip your furnace’s limit switch which will shut off the furnace’s burners, therefore, there will be no heat. To prevent this from happening, check your air filters regularly and replace dirty ones with new ones.
3. Check your vents. It’s important to make sure the airflow to your furnace is unrestricted. Go through your home and make sure all vents throughout your home are open (even in rooms you don’t use) and unobstructed by furniture or other items.

If your thermostat is set to the proper settings, your air filter is clean and your vents are open and unobstructed, contact an HVAC technician to diagnose your problem.

The most common cause of a furnace not turning on is a tripped breaker. Oftentimes, this happens if the furnace is being overworked.

Before you reset your furnace breaker, make sure you address the issues mentioned above in “Common Issue #1.” If your vents are open and unobstructed, locate your electrical panel and find the breaker marked furnace or HVAC. Move the switch to the OFF position, then to the ON position.

If your breaker trips again, do not try to reset it. A furnace breaker that continues to trip is a sign that something more serious is likely happening and you’ll need to contact an HVAC technician to diagnose the issue.

While furnaces never operate completely silently, you should never hear excessive noise like banging or grinding sounds when the furnace is running. Even a consistent low buzzing sound can be a symptom of a more serious problem. So, if you’re hearing strange noises, it may be a good idea to call an HVAC professional to check it out.

Here are some common causes of strange noises:

• The blower motor belt is damaged
• A fan blade is nicked
• There’s a loose bolt or another component that’s lodged inside the blower fan or motor
• A broken blower mount, which can cause the blower motor to lean or to fall
• Worn bearings which may need to be inspected and lubricated

If you have an older furnace and the metal components have excessive rust or corrosion, you may need to replace your model with a newer, high-efficiency model. If you’re hearing strange noises, immediately turn your furnace off to prevent further damage and call an HVAC pro.