Common Furnace Problems and How to Troubleshoot Them

Furnace problems are a common occurrence for homeowners. And when it stops working properly, you can feel the effects almost immediately.

In order to avoid surprises, it’s important to know what your furnace might be experiencing and how to troubleshoot it yourself.

Furnace Problem Diagnosis

Identifying common furnace problems can at the very least help you determine whether to call in a professional.

Here are several reasons why your furnace might not be working properly.

Dirty Air Filters

Essentially, the job of an air filter is to trap dust and debris, maintaining good air quality in your home.

However, over time, they can become clogged with dust, dirt, and debris, which can reduce their efficiency.

When this happens, your furnace will be forced to work harder to produce the same amount of heat, which can shorten its lifespan and increase your energy bills.

Thermostat Problems

The thermostat on your furnace functions as the nerve center, controlling and regulating heat production to keep your home comfortable.

When the thermostat fails, you may have sporadic heat, no heat, or rapid temperature changes that might leave you shivering one minute and sweating the next.

Insufficient Heating

When your space doesn’t seem to heat adequately, it can be more than just a minor inconvenience.

Insufficient heating can be caused by various factors, including incorrect thermostat settings or blocked heat registers, which can reduce airflow and affect heat distribution.

Alternatively, your furnace’s capacity may be insufficient for the size of your space, necessitating an upgrade to a larger unit.

Frequent Cycling

No one enjoys a furnace that jumps between “On” and “Off” modes all the time. This frequent cycling could indicate a clogged filter, improper airflow, or even faulty thermostat settings.

Such erratic behavior not only disrupts your comfort but also decreases your furnace’s overall efficiency.

Noise Issues

Sounds like shaking, rattling, or banging emanating from your furnace can be rather unsettling. These unusual noises often point towards mechanical issues, loose components, a damaged blower wheel, or an airflow reduction that could compromise your furnace’s performance.

Ignition Problems

Furnaces need a spark or heat source to light up the gas and produce heat. This process is managed by an ignition system, which can be either a hot surface ignition or an intermittent pilot.

• Hot Surface Ignition: This system uses a small heating element, similar to a tiny stove burner, to ignite the gas. When you turn on the furnace, the heating element gets hot and ignites the gas.
• Intermittent Pilot: This system uses a tiny gas flame, called a pilot light, to ignite the gas when needed. The pilot light is ignited by an electric spark when the thermostat calls for heat.

If the ignition system fails to work, the furnace won’t light up, leaving your home without heat. This failure can be caused by simple issues like a clogged flue, a malfunctioning switch, or too much draft in the pilot area.

Leaky Ducts

Leaky ducts can prove to be a major nuisance as they allow heated air to escape before reaching its intended destination, creating inconsistent temperatures and increasing heating costs. This issue further stresses your furnace, decreasing its efficiency and lifespan.

Blower Continuously Running:

The blower plays a key role in circulating warm air throughout your home. If it keeps running relentlessly, there could be a problem with the limit switch, which may require professional assistance to replace.

Odors or Strange Smells

If you detect one of these strange smells from your furnace, it could be a sign there’s something wrong.

• Musty smell: If you notice a musty smell, it might point to a mold issue in your furnace system
• Burning Smell: If you catch a smell similar to burning or hot metal, it may suggest that a part inside your furnace is overheating. This could lead to bigger issues down the line if not addressed.
• Rotten eggs smell: A smell like rotten eggs is an important warning signal as it could mean there’s a gas leak. This is particularly dangerous and needs immediate attention.

Cracked Heat Exchanger

Heat exchangers are vital for supplying warmth throughout your home, but when they crack, they can cause major issues such as dangerous carbon monoxide leaks.

Usually, these cracks occur due to fluctuations in temperature, corrosion, or the natural consequences of long-term usage.

Normal Wear and Tear

While furnaces are built to withstand years of usage, they do wear out after a period of time, which could lead to operational problems.

Wear and tear can affect belts, bearings, and fan motors, causing inefficient heating and airflow problems.

Belts may loosen or break, and worn-out bearings can increase friction, contributing to the overall strain on your furnace.

Furnace Troubleshooting Tips

Check the Power Supply

Before jumping to any conclusions, the first thing you should do is make sure the furnace is plugged into a power outlet.

It’s surprising how often a furnace isn’t working simply because it isn’t getting power.

Check The Thermostat Settings

Check to see whether your thermostat is set to ‘heat’. If it’s not, your furnace won’t turn on. Also, compare the temperature setting with the room’s temperature. If it’s set lower than the room temperature, increase the setting by a few degrees and see if the furnace turns on.

Check The Furnace Filter

Gently remove the filter for inspection, taking care not to release dust into the air. Hold it up to the light; if it appears dirty or clogged, a replacement or cleaning is in order.

Inspect the Furnace Flame

The furnace flame color is a good indicator of whether your furnace is operating correctly. A properly working furnace should have a blue flame.

If you see a yellow or orange flame, this can indicate a problem. It may simply mean your furnace requires cleaning, or it could be a more severe issue, such as a gas leak.

Verify Gas Supply Is On

Check the gas supply if you’re using a gas furnace. Make sure that the valve is open and supplying gas to the furnace. If your other gas-powered appliances are working fine, then the problem is likely elsewhere.

Check for Blockage in the Exhaust Flue

Over time, the exhaust flue of your furnace can get obstructed by debris or animal nests. If the flue pipe is blocked, it can shut off your unit’s operation.

Make sure that your flue pipe is clear of obstructions, and if there is any blockage, think about contacting a professional.

Reset The Circuit Breaker

If your furnace is not turning on, your circuit breaker might have tripped. Locate the breaker for the furnace on your electrical panel and ensure it is in the “on” position. If it’s off, flip the switch to reset it.

Inspect The Furnace Switch

Many furnaces have a switch (looking much like a light switch) on or near the unit, which should be in the “on” position.

Check the Pilot Light (for Older Models)

On older furnaces, there’s a small flame known as the pilot light that should be always lit for the furnace to function.

If it’s out, you can try to relight it following the instructions on the furnace, or refer to the owner’s manual.

Be cautious. If you smell gas, it might be risky to attempt to relight it.

Examine the Gas Valve

Your furnace uses a supply of gas to operate. Typically, a gas valve controls the flow. Make sure this valve is fully open. If it’s even partially closed, the furnace won’t have access to the necessary amount of gas to produce heat.

Inspect the Flame Sensor or Thermocouple

Parts like the flame sensor or thermocouple are key safety features in your furnace. They detect when a flame is present when the gas is on. If they’re faulty or dirty, they may “think” there’s no flame and shut down the gas to prevent a dangerous situation.

Clear Any Vents or Duct Blockages

Furnaces rely on a series of ductwork and vents to distribute hot air. If these are blocked by dust, furniture, or other debris, the furnace can overheat or become less efficient. Make a habit of routinely checking for any obstructions in your ventilation system.

Examine the Blower Motor and Belt

The blower motor propels hot air through your vents. If it’s damaged or if the belt is broken or loose, your furnace will still be producing heat, but it won’t be correctly distributed. Keep an eye out for any signs of wear or damage to these components.

Check for Dirty or Corroded Burners

The burners in your furnace can get dirty or corroded over time, affecting their ability to ignite the gas. If this is the case, you might need to clean them or have them replaced.

Listen for Unusual Noises

Furnaces can make noises. But bangs, whines, or creaks could indicate a problem. Note down any unusual sounds to help a technician diagnose potential issues.

Test Safety Switches

Most furnaces have several safety switches (usually on the door and blower motor). You should periodically test these switches to ensure they’re functioning correctly.

Inspect Ignition System

Depending on your furnace, it might use either a hot surface ignition or an intermittent pilot to ignite the gas. Make sure the ignition is working correctly and igniting the gas as it should.

Restart the System by Turning It Off and on Again 

Minor issues can sometimes be resolved with a simple power restart. So turn off your furnace at its power source, wait a few minutes, then turn it back on.

Furnace Repair Solutions

When it comes to furnace repair solutions, you should ask yourself these questions: Can I fix the problem or should I call a professional?

While you might want to solve your furnace problem yourself to save money, you should always be aware of your own limitations.

If there’s a problem with your furnace, it’s best to call a professional for help, as this will save you time and money in the long run.

But that said, here are problems you can resolve by yourself and issues that require a technician’s expertise.

Self-Solvable Furnace Problems

• Thermostat issues
• Dirty air filters
• Pilot light problems
• External switch issues
• Circuit breaker problems

Problems Requiring a Meadow Air Technician

• Mechanical wear and tear
• Ignition or heat control issues
• Carbon monoxide leaks
• Frequent cycling problems
• Blower issues
• Strange noises
• Persistent pilot light issues
• No heat or reduced heat
• Faulty components
• Inconsistent heating

Furnace Maintenance and Prevention Tips

Just like any other piece of equipment in your home, your furnace requires regular maintenance to ensure optimal performance and longevity.

Here are some preventative measures you can take to keep your furnace running as it should.

• Regular Inspections:   Inspect your furnace at least once a year, ideally before the cold season begins. This will ensure that potential issues are identified and rectified before they escalate.
• Filter Replacement: As mentioned, a dirty filter can cause a myriad of problems. It’s best to replace or clean your filters every 1-3 months, depending on usage and the type of filter you have.
• Duct Cleaning: Over time, the duct system can accumulate dust, debris, and even mold. It’s good practice to have your ducts professionally cleaned every few years.
• Regularly Check the Thermostat Battery: A dead battery can lead to unnecessary issues, so ensure it’s replaced as needed.
• Ensure Clear Ventilation: Regularly check the external vents to make sure they are not obstructed by snow, debris, or any other barriers.
• Keep the Area Around the Furnace Clear: Ensure the space around your furnace is free from combustibles and clutter. This not only ensures optimal efficiency but is also a crucial safety measure.
• Regular Lubrication: Some parts of the furnace, like the blower motor, may need periodic lubrication to function smoothly.

Facing Furnace Trouble? Call Meadow Air

At Meadow Air, we understand the importance of a well-functioning furnace, especially during the colder months. We’re committed to ensuring that your home remains a comfortable sanctuary. 

Whether you’re faced with a minor furnace hiccup or require a complete system overhaul, our team of certified professionals is here to help. With years of experience under our belts, we pride ourselves on offering prompt, efficient, and affordable services.

Need help? Don’t sweat it – contact us today for all your HVAC solutions.