The Most Common Furnace Problems and Solutions

Going into the cold winter months, you’ll want to ensure all your HVAC systems are a-go. You don’t want to find yourself shivering in your bed, dreaming of being warm again.

You’ll also need to know what problems you should be looking out for. You don’t want to end up in a situation where you’re freezing in the middle of the night, after all!

Luckily, we can help you figure out what you should be looking out for. Let’s go through the most common furnace problems and how to fix them.

Filter Problems

You need to pay careful attention to your home furnace’s filter.

One prevalent issue is dirty or clogged filters. Over time, filters accumulate dust, debris, and pet dander, obstructing the airflow. This restriction can strain the furnace, reduce heating efficiency, and potentially cause damage.

Regularly checking and replacing or cleaning filters can fix this issue. This simple act ensures proper airflow, prevents strain on the furnace, and optimizes heating performance.

Another problem stemming from dirty filters is reduced airflow. When filters are clogged, the furnace has to work harder to push air through. This increased workload can overheat the furnace and cause uneven heating throughout your space.

Additionally, it leads to increased energy consumption as the furnace struggles to maintain the desired temperature. By replacing or cleaning filters as needed, you can mitigate these issues, promoting efficient airflow and reducing energy usage, subsequently lowering heating costs.

Pilot Light

Pilot light problems are another of the many furnace issues you should watch out for. A properly functioning pilot light is crucial for the ignition and operation of many gas furnaces. 

One of the frequent issues is a pilot light that won’t stay lit. This can be caused by a dirty or damaged pilot light orifice or a faulty thermocouple. If the pilot light goes out frequently or doesn’t stay lit, it can prevent the furnace from turning on and heating your home.

Or, get help from a professional HVAC technician to help you figure out the underlying cause of the pilot light problem.

A weak or flickering pilot light can also cause problems. If the pilot light is not strong enough, it may not generate sufficient heat to ignite the main burners.

That will lead to inadequate heating. This can be caused by a dirty or partially blocked pilot orifice or a weak gas supply. Regular maintenance and cleaning of the pilot assembly can help maintain a strong and steady pilot light, ensuring it ignites the main burners effectively.

Broken Thermostat

One prevalent problem is inaccurate temperature readings or an unresponsive thermostat. If the thermostat is unable to accurately detect and control the temperature, it can lead to inconsistent heating or cooling within your home.

This can be frustrating and uncomfortable, especially during extreme weather conditions. To address this, troubleshooting the thermostat, calibrating it, or replacing it if necessary can restore proper temperature regulation.

A thermostat that doesn’t turn the furnace on or off is also a problem. This can be due to different wiring issues, a faulty relay, or internal malfunctions.

When the thermostat fails to signal the furnace to start, it results in no heat being produced. If the thermostat doesn’t signal the furnace to stop when the desired temperature is reached, the furnace may overheat your home.

Proper wiring, ensuring the thermostat is compatible with your heating system, or replacing the thermostat may resolve these issues, allowing for efficient and accurate control of your furnace.

Lack of Heat

Experiencing a lack of heat from your furnace is a common problem, especially during colder seasons.

You could have a malfunctioning blower mower. The blower motor circulates warm air throughout a building.

If it’s not functioning correctly, the airflow may be weak. Timely repairs or replacements of the blower motor can restore proper airflow and resolve this issue.

Insufficient heat could be due to gas supply issues. If there’s a problem with the gas line, gas valve, or pilot light, the furnace may not be receiving the fuel needed to generate heat. Check the gas supply and relight the pilot light. If these things don’t work, try and bring in the professionals for their input.

Weird Noises

Weird noises emanating from your furnace can be a cause for concern and may indicate underlying furnace issues. One common problem is a furnace making banging, popping, or creaking noises.

These sounds often result from the expansion and contraction of the furnace’s ductwork and components as they heat up and cool down.

Ensure the furnace’s components are securely in place. That will reduce unusual sounds and maintain efficient furnace performance.

Squealing or whistling noises are another common problem. These sounds are often caused by issues with the blower motor or the blower wheel.

Over time, these components may become loose, misaligned, or worn out, resulting in irritating sounds. To prevent these problems, regularly lubricate the blower motor.

Rattling or vibrating sounds can be caused by loose panels or screws within the furnace or even debris trapped in the vents. Properly securing panels, tightening screws, and ensuring that vents and ducts are clear of any obstructions can eliminate these noises and prevent potential damage to the furnace.

Frequent Cycling

Frequent cycling of your furnace is where it turns on and off frequently.

One prevalent cause is an improperly sized furnace. If your furnace is too large for your space, it will heat quickly and shut off, only to turn on again shortly after.

An undersized furnace may struggle to reach the desired temperature, leading to frequent cycling. Bring in HVAC professionals to see if they recommend installing a new furnace.

Issues with the furnace’s flame sensor or ignition system can also cause frequent cycling. If your home’s flame sensor is dirty or faulty, it may incorrectly detect the flame, causing the furnace to shut off and restart.

Clean the fire sensor regularly. You should also inspect the ignition system and see if there are any problems.

Problems With the Ductwork

Problems with the ductwork can significantly affect the efficiency and performance of your furnace. You’ll want to watch out for leaky ducts.

When there are leaks or gaps in the ductwork, heated air escapes before it reaches the intended rooms, resulting in wasted energy and reduced heating efficiency.

Properly fixing a furnace by sealing any leaks using sealant can significantly improve airflow and heating efficiency, ensuring that the warm air reaches its intended destination.

You should also keep an eye on your insulation. Ducts that lack proper insulation, especially when passing through unconditioned spaces like attics or crawl spaces, can lead to heat loss.

To address this, insulating the ductwork with appropriate insulation materials helps minimize heat loss and ensures that heated air is effectively delivered to the living spaces.

Blocked or restricted airflow within the ducts is a frequent problem caused by obstructions, debris, or improper installation.

This can diminish the amount of heated air that reaches the rooms. Check for any obstructions, and get them removed if you see any. You can even invest in duct cleaning services.

Issues With the Gas Supply

There are further issues with your furnace’s gas supply you might want to look out for.

One of the primary issues is a disrupted or insufficient gas supply. A furnace relies on a steady and adequate supply of natural gas or propane to generate heat.

If the gas supply is interrupted due to a closed gas valve, a gas leak, or an issue with the gas line, the furnace won’t ignite or operate properly, resulting in no heat.

To address this, ensure that the gas valve supplying the furnace is open and functioning correctly.

Another common problem is a malfunctioning or dirty gas burner. Over time, gas burners can accumulate dirt, debris, or rust, hindering proper ignition and heat production. Additionally, misaligned or damaged burners may fail to ignite the gas effectively.

Cracked Heat Exchanger

The heat exchanger is a crucial component that transfers heat from the furnace’s combustion chamber to the air being circulated through your home. That might mean you need to invest in fixing a furnace.

When it cracks, it can leak harmful gasses like carbon monoxide into your living spaces. Carbon monoxide is a colorless, odorless gas that can be lethal in high concentrations.

Identifying a cracked heat exchanger can be challenging since it’s not always visible. Some signs include a strong and unusual odor, such as a metallic or chemical smell, or visible signs of corrosion or damage.

If you suspect a cracked heat exchanger, it’s crucial to shut off the furnace immediately and contact a professional HVAC technician to conduct a thorough inspection and evaluation.

The solution to a cracked heat exchanger is typically replacing it or, in some cases, replacing the entire furnace. Repairing a cracked heat exchanger is often not recommended due to the cost, complexity, and potential safety risks involved.

Address These Common Furnace Problems Today

Now that you know the most common furnace problems, you can work to avoid them! Do a deep dive into your system and take all the necessary preventative.

Do you need HVAC services in the Port Huron area? Look no further. It’s Your Heating and Cooling Guy has been helping Michigan homeowners since 2001. Reach out today!