Inspecting the Furnace Blower Motor: A Step-by-Step Guide


Regular maintenance is crucial for ensuring optimal performance and efficiency of gas furnaces, modern furnaces, air furnaces, and the overall HVAC system. One essential component that requires inspection is the furnace blower motor in gas furnaces and air furnaces. It is an important part of the HVAC system and heating unit. This blog post provides an overview of the furnace blower motor inspection process for HVAC systems, highlighting its importance in maintaining proper heat circulation throughout your home. Gas furnaces, air furnaces, and high-efficiency furnaces all rely on a functioning blower motor to distribute warm air effectively.

A faulty blower motor can significantly impact the performance of your gas or air furnace, leading to issues such as inadequate heat distribution and reduced energy efficiency in your HVAC system or heating unit. By inspecting the blower motor of gas furnaces, a furnace inspector can identify signs of wear, damage, or malfunction early on, allowing for timely repairs or replacements. This is especially important for efficiency gas furnaces, as maintaining their efficiency is crucial.

During the inspection process of gas furnaces, it is important for the inspector to follow the manufacturer’s instructions and safety guidelines. This includes checking the pipes and ensuring the pilot light is functioning properly. Checking for any loose connections, unusual noises, or signs of overheating are key steps to ensure that your gas and air furnaces operate smoothly and effectively. It is important to have an inspector regularly check these fuel-powered appliances.

By understanding how to inspect and maintain your furnace blower motor properly, you can ensure a comfortable living environment with efficient heating throughout your home. This applies to both air furnaces and gas furnaces. It is important to have an inspector regularly check the fuel used by your furnace to ensure it is functioning optimally.

Understanding Furnace Blower Motors

The blower motor in gas furnaces and air furnaces is essential for the fuel-powered heating system to function properly and provide gravity warm. The gas furnaces heating unit is responsible for circulating the air throughout the furnace and distributing it to different parts of your home. It is important to have a fuel inspector regularly check your gas furnaces heating unit. Let’s explore the different types of blower motors used in heating units, understand their role in circulating air, and discuss common issues that can arise with these motors fueled by upflow systems.

Different Types of Blower Motors Used in Furnaces

Furnace blower motors, commonly used in gas furnaces, are available in various types to suit different applications. These motors are designed to enhance the efficiency of the heating unit and can include gravity systems. The two most commonly used types of gas furnaces are the permanent split capacitor (PSC) motor and the electronically commutated motor (ECM). These motors are used in the heating unit of an air furnace.

  1. The Permanent Split Capacitor (PSC) Motor is a widely used type of motor in older furnaces. It ensures pilot efficiency by utilizing gravity and air to enhance performance. The downflow furnace operates with efficiency and gravity, utilizing a fixed speed and simple design. This air furnace is highly effective. PSC motors are reliable but less energy-efficient compared to ECM motors, especially when it comes to gas furnaces. The efficiency of gas furnaces can be improved by using ECM motors instead of PSC motors. Additionally, some older gas furnaces still rely on gravity for heat distribution, which can further impact their efficiency.

  2. Electronically Commutated Motor (ECM) for furnaces: ECM motors are more advanced and energy-efficient than PSC motors, making them a great choice for improving air circulation. They use advanced technology to vary the speed of their furnaces based on the heating demands, resulting in better energy savings for the air. ECM motors also offer better airflow control and quieter operation for furnaces.

The Role of the Blower Motor in Circulating Air Throughout the System

The furnace blower motor is responsible for moving air through the heating system, ensuring proper circulation and distribution of warm air throughout your home. Furnaces play a crucial role in maintaining a comfortable temperature in your living space. Here’s how it works:

  1. Air Intake: The blower motor pulls cool air from your home into the furnaces through an intake vent or return duct.

  2. Heat Exchange: Inside furnaces, heat is generated by burning fuel or electric resistance coils, which warms up the air.

  3. Blowing Hot Air: The furnace blower motor pushes heated air over a furnace heat exchanger before distributing it through supply ducts to different rooms.

  4. Return Path: As warm air from the furnaces circulates through your home, it eventually cools down. The blower motor then pulls the cooled air back into the furnaces through return ducts to repeat the heating process.

Common Issues That Can Arise with Blower Motors

While furnace blower motors for air furnaces are generally reliable, they can experience issues over time. Here are some common problems you may encounter:

  1. Furnaces: Motor Failure: Overheating, worn-out bearings, or electrical issues can cause the blower motor to fail. Air. Signs of furnace motor failure include no airflow or unusual noises coming from the furnaces.

  2. Blower Wheel Damage: The blower wheel in furnaces is responsible for efficiently moving air. If furnaces become damaged or clogged with debris, it can affect airflow and reduce system performance.

Pre-Inspection Safety Measures

Pre-Inspection Safety Measures

Before inspecting the furnace blower motor, it is crucial to take certain safety measures to protect yourself and ensure a safe environment for both furnaces and air. These precautions are essential to prevent accidents and potential harm when dealing with furnaces and air. Here are some important steps to follow:

  1. Turn off power to the air furnace: It is crucial to turn off the power supply to the furnaces before starting any inspection or maintenance work. This ensures that there is no risk of electrical shocks or accidents while examining the blower motor in furnaces and air conditioning units.

  2. Wear appropriate safety gear when inspecting furnaces and air systems: To protect yourself during the furnace and air inspection process, make sure you wear suitable safety gear such as gloves and goggles. Gloves provide protection from sharp edges or any debris that may be present, while goggles shield your eyes from dust particles or other potential hazards when working with furnaces and air.

  3. Before starting any inspection of furnaces, it is essential to check for any signs of gas leaks or carbon monoxide presence in and around the air furnace area. Gas leaks from furnaces can be detected by their distinct smell, while carbon monoxide from furnaces can be identified using a carbon monoxide detector.

Inspectors should prioritize air safety above all else during home inspections, especially when dealing with potentially hazardous components like furnaces. By following these pre-inspection safety measures for furnaces, inspectors can minimize risks and ensure a safe working environment for air.

Steps for Basic Furnace Blower Inspection

Removing Access Panels

To inspect the furnace blower motor and ensure proper functioning of the air circulation system, start by removing the access panels. These panels are typically located on the front or sides of the furnace and are designed to facilitate proper airflow and ventilation for the air conditioning system. Carefully unscrew or unclip the panels to gain access to the air blower motor compartment. Before attempting any inspection, make sure to turn off the power supply to the furnace to ensure the safety of the air.

Inspecting the Blower Wheel

Once you have removed the access panels, it’s time to inspect the air blower wheel. Take a close look at the wheel for any debris or damage that may be affecting its performance in the air. Debris such as dust, dirt, or even small objects can accumulate on the wheel over time and hinder its ability to circulate air effectively. Use a flashlight if needed to get a better view of any potential obstructions in the air.

If you notice any debris in the air on the blower wheel, carefully remove it using a soft brush or cloth. Be gentle while cleaning to avoid causing further damage. Check for any signs of wear and tear on the wheel itself, including damage to the air. If there are visible cracks or broken blades in the air blower wheel, it may be necessary to replace the blower wheel altogether.

Lubricating Motor Bearings

Another important step in inspecting a furnace blower motor is lubricating its bearings if necessary to ensure proper airflow and ventilation. Over time, the air bearings can become dry and cause friction within the motor, leading to increased wear and reduced efficiency. Referencing your furnace’s manufacturer guidelines, identify whether your specific model requires air lubrication and what type of air lubricant should be used.

If air lubrication is required, locate the air oil ports on either end of the motor shaft and apply a few drops of air lubricating oil into each port. This will help reduce friction and ensure smooth operation of your furnace’s blower motor, allowing for optimal airflow and circulation of air.

Remember that not all furnaces require air lubrication for their motors. Some models feature sealed bearings that do not need regular maintenance in regard to air. Always consult the manufacturer’s instructions or seek professional advice if you are unsure about whether your furnace motor requires air lubrication.

By following these steps for basic furnace blower inspection, you can ensure that your air blower motor is in good working condition. Regular maintenance and inspection of the blower motor will help prolong its lifespan and improve the overall efficiency of your furnace system. This is essential for ensuring proper circulation of air throughout your home.

Diagnosing a Faulty Blower Motor

Signs of a Malfunctioning Blower Motor

Recognizing signs of a malfunctioning air blower motor is crucial in maintaining the efficiency and performance of your furnace. One common indicator of a problem with the air system is unusual noises coming from the blower motor, such as grinding, squealing, or rattling sounds. These noises may suggest worn-out air bearings or loose air components within the motor. Another sign to watch out for is weak airflow from the vents. If you notice that your home isn’t being heated or cooled properly, it could be due to a faulty blower motor.

Checking Electrical Connections and Wiring

To diagnose a faulty blower motor, it’s important to check the electrical connections and wiring associated with it. Start by turning off the power supply to the furnace to ensure safety. Inspect the wiring for any signs of damage or loose connections. If you find any issues, carefully tighten or replace them as necessary. It’s also essential to examine the control board and thermostat connections for any faults that may affect the blower motor’s operation.

Testing the Capacitor

The capacitor plays a vital role in providing an extra boost of power to start up the blower motor. Over time, capacitors can weaken or fail altogether, resulting in issues with the blower motor’s functionality. To determine if your capacitor needs replacement, you can perform a simple test using a multimeter set on capacitance mode. Start by disconnecting power from your furnace and discharging any stored energy in the capacitor before removing it for testing. Follow proper safety procedures while handling capacitors as they can still hold an electrical charge even when disconnected.

Once you have removed the capacitor, use your multimeter to measure its capacitance value. Compare this reading with the manufacturer’s recommended range; if it falls significantly below that range, it indicates a faulty capacitor that needs replacement.

By inspecting these critical components – the blower motor, electrical connections, wiring, and capacitor – you can diagnose potential issues and take appropriate action to ensure your furnace operates efficiently. Regular maintenance and prompt repairs will not only extend the lifespan of your blower motor but also contribute to the overall performance of your heating and cooling system.

Testing the Blower Motor and Related Components

To ensure that the furnace blower motor is functioning properly, there are several important tests that can be performed. These tests will help determine if the motor is receiving the correct voltage supply, if its windings have continuity, and if the fan limit switch is operating as it should.

Using a Multimeter to Check for Proper Voltage Supply to the Motor

One way to test the blower motor is by using a multimeter. This tool allows you to measure electrical voltage and check if the motor is receiving the appropriate power supply. Start by turning off the furnace and disconnecting power to avoid any accidents.

Next, locate the wiring diagram for your specific furnace model. This diagram will indicate which wires are responsible for powering the blower motor. Use your multimeter’s probes to test these wires for voltage. Place one probe on each wire and set your multimeter to measure AC voltage.

If you’re getting a reading close to or within the specified range in your furnace’s manual, then it indicates that power is reaching the blower motor correctly. However, if there is no voltage detected or an abnormal reading, it may suggest an issue with either the thermostat or another component in the system.

Testing The Motor’s Windings for Continuity

Another critical test involves checking for continuity in the motor’s windings. Continuity refers to an uninterrupted flow of electrical current through a circuit. To perform this test, start by disconnecting power from your furnace.

Locate and access the blower motor by removing any necessary panels or covers. Once exposed, use a multimeter set on resistance mode (ohms) and touch one probe to each terminal of the motor’s winding connections.

A low resistance reading indicates good continuity in that particular winding, while a high resistance reading suggests a break in continuity or a faulty winding. If any of these readings are outside of their specified range, it may be necessary to replace the blower motor.

Checking the Fan Limit Switch for Proper Operation

The fan limit switch is a safety device that controls when the blower motor turns on and off. It also monitors the temperature within the furnace. If this switch malfunctions, it can lead to issues with airflow and heating performance.

To check if the fan limit switch is operating correctly, start by turning off power to your furnace. Locate the switch, which is usually located near or on top of the furnace’s heat exchanger. The switch will have a dial or lever that allows you to adjust its settings.

Using a multimeter set on continuity mode (ohms), touch one probe to each terminal of the fan limit switch.

Additional Considerations for Gas Furnaces

Inspecting the Heat Exchanger

Inspecting the heat exchanger is an essential step in maintaining a gas furnace. The heat exchanger is responsible for transferring heat from the combustion process to the air that circulates throughout your home. It’s crucial to check for any cracks or corrosion in the heat exchanger, as these issues can lead to carbon monoxide leaks and potential health hazards.

Checking Gas Valve Operation and Pressure Levels

The gas valve plays a vital role in controlling the flow of fuel into your furnace. Ensuring that the gas valve operates correctly is crucial for the safe and efficient operation of your gas furnace. During an inspection, HVAC professionals will verify that the gas valve opens and closes properly and that it maintains adequate pressure levels. This helps prevent issues such as insufficient heating or a complete failure of the heating system.

Verifying Proper Venting and Exhaust System Functionality

Proper venting and exhaust system functionality are essential for safely removing flue gases produced during combustion. During an inspection, technicians will examine the venting system to ensure it is free from blockages or damage that could impede proper airflow. They will also check if the exhaust system effectively removes combustion byproducts without any leaks, which could pose health risks.

Gas furnaces rely on a well-functioning ventilation system to maintain optimal performance while ensuring safety within your home.

By inspecting these components regularly, you can identify any potential issues before they become major problems, helping you avoid costly repairs or even replacement of your entire HVAC system.

Remember, regular maintenance not only improves efficiency but also extends the lifespan of your gas furnace.

DIY Maintenance Tips for Furnace Blowers

Regularly cleaning or replacing air filters is an essential step in maintaining the efficiency of your furnace blower motor. Clogged air filters can restrict airflow, causing the blower motor to work harder and potentially overheat. By keeping the air filters clean, you ensure that the blower motor operates smoothly and efficiently.

Keeping the blower assembly clean and free from dust and debris is another crucial aspect of furnace maintenance. Over time, dust and debris can accumulate on the blower blades, reducing their effectiveness and impeding proper airflow. Regularly inspecting and cleaning the blower assembly will help prevent any blockages or obstructions that could hinder its performance.

Ensuring proper airflow throughout your HVAC system is vital for optimal functioning of the furnace blower motor. Obstructed vents and registers can disrupt the flow of air, putting unnecessary strain on the blower motor. Make sure to keep all vents and registers unobstructed by furniture, curtains, or other objects to maintain steady airflow.

In addition to these DIY maintenance tips, it’s important to note that certain aspects of furnace inspection should be left to a professional HVAC technician. While regular cleaning and filter replacement can be done by homeowners, more complex tasks such as inspecting vent connector pipes or troubleshooting issues with an upflow highboy furnace should be handled by a trained technician.

A combination of regular DIY maintenance tasks along with professional inspections will ensure its longevity and efficient operation. By following these tips, you can prevent potential problems before they arise and keep your heating system running smoothly throughout the year.

Recognizing and Addressing Unsafe Conditions

Identifying potential fire hazards

During the inspection of your furnace blower motor, it is crucial to be aware of potential fire hazards. Loose wiring can be a significant risk, as it can cause electrical arcing or short circuits that may lead to fires. Inspecting the wiring connections and ensuring they are secure can help mitigate this danger. Overheating components can pose a fire hazard. Check for any signs of excessive heat, such as discoloration or melting around the motor or other parts.

Addressing gas leaks or carbon monoxide risks immediately

Another critical aspect of inspecting your furnace blower motor is addressing any gas leaks or carbon monoxide risks promptly. Gas leaks can occur due to faulty connections or damaged gas lines, which poses a severe threat to your safety. It’s essential to check for the smell of gas and listen for hissing sounds near the furnace. If you suspect a gas leak, evacuate the area immediately and contact a professional technician.

Carbon monoxide (CO) is an odorless and colorless gas that can be produced by malfunctioning furnaces. Exposure to high levels of CO can result in serious health issues or even death. To ensure your safety, consider installing carbon monoxide detectors near your furnace and regularly check their functionality.

Taking necessary precautions to prevent electrical shocks

Inspecting the furnace blower motor involves working with electricity, which presents a risk of electrical shocks if proper precautions are not taken. Before starting any inspection procedures, make sure to turn off the power supply to the furnace at the circuit breaker panel. This step will help prevent accidental contact with live wires during the inspection process.

When examining electrical components within the furnace blower motor, avoid touching any exposed wires without protective gear such as insulated gloves. Furthermore, refrain from using metallic tools when handling electrical parts to minimize the risk of electric shock.

Remember that if you are unsure about any aspect of inspecting the furnace blower motor or encounter potential safety hazards, it is always best to seek assistance from a qualified HVAC technician. They have the expertise and knowledge to handle such situations safely and effectively.

Complying with Manufacturer’s Specifications and Codes

To ensure the safe and efficient operation of your furnace blower motor, it is essential to follow the manufacturer’s guidelines for maintenance and inspection procedures. These guidelines are specifically designed to optimize performance and extend the lifespan of your equipment.

Adhering to local building codes and regulations is equally important when inspecting the furnace blower motor. Building codes are put in place to ensure that installations meet certain standards for safety, efficiency, and reliability. By complying with these codes, you can help prevent potential hazards and ensure that your system operates within acceptable limits.

If you are unsure about specific requirements or find it challenging to interpret the manufacturer’s instructions or building codes, it is always best to seek professional assistance. A qualified technician will have the knowledge and expertise to properly inspect your furnace blower motor, identify any material defects or issues, and address them accordingly.

When inspecting the furnace blower motor, one crucial aspect to consider is proper voltage supply. It is essential to verify that the voltage supplied to the motor matches the manufacturer’s specifications. Deviations from these specifications can lead to inefficiencies, premature wear, or even complete failure of the motor.

Another important element to examine during an inspection is the wiring connected to the furnace blower motor. Ensure that all wires are securely fastened and free from any signs of damage or wear. Loose connections or frayed wires can result in poor performance or electrical hazards.

Steady state efficiency is another factor that should be evaluated during an inspection. This metric measures how effectively a furnace blower motor converts electrical energy into mechanical energy while operating under normal conditions. Checking for steady state efficiency helps determine if there are any inefficiencies in the motor’s operation that may require attention.

By following manufacturer’s specifications and adhering to local building codes when inspecting your furnace blower motor, you can ensure its safe operation, optimal performance, and longevity. Seeking professional assistance when needed and paying attention to details such as proper voltage supply, wiring integrity, and steady state efficiency will help keep your motor running smoothly.


In conclusion, understanding and inspecting furnace blower motors is crucial for maintaining the efficiency and safety of your heating system. By following the steps outlined in this article, you can diagnose and address issues with your blower motor, ensuring optimal performance and preventing potential hazards. It is essential to prioritize safety by taking pre-inspection measures and recognizing and addressing any unsafe conditions that may arise.

Regular maintenance and DIY tips can go a long way in keeping your furnace blower motor in top shape. However, it is important to remember that certain tasks should be left to professionals, especially when dealing with gas furnaces. Always comply with manufacturer’s specifications and codes to ensure the longevity of your system.

By implementing these practices and staying proactive in maintaining your furnace blower motor, you can enjoy a well-functioning heating system that provides comfort and peace of mind throughout the year.

Frequently Asked Questions


Q: What is a furnace blower motor?

A furnace blower motor is an essential component of a heating system. It is responsible for circulating air throughout the furnace and distributing it to different areas of the house. The motor helps maintain a consistent temperature by pushing the heated air through the ductwork.

Q: Why should I inspect my furnace blower motor?

Regular inspection of your furnace blower motor ensures its proper functioning, improves energy efficiency, and prevents potential breakdowns. By identifying any issues early on, you can save money on costly repairs and ensure that your heating system operates safely and effectively.

Q: How do I test if my blower motor is faulty?

To test if your blower motor is faulty, turn off the power supply, remove the access panel, and visually inspect for any signs of damage or wear. Check for unusual noises or vibrations when the furnace is running. You can also use a multimeter to measure voltage at the motor’s terminals to determine if it’s receiving power.

Q: Can I perform maintenance on my furnace blower myself?

Yes, you can perform basic maintenance tasks on your furnace blower yourself. This includes cleaning or replacing air filters regularly, lubricating moving parts as recommended by the manufacturer, and keeping the area around the blower clean and free from debris. However, complex repairs should be left to professionals.

Q: Are there any safety measures I need to follow during inspection?

Yes, it’s crucial to follow pre-inspection safety measures when inspecting your furnace blower motor. Ensure that power supply to the unit is switched off before starting any work. Use appropriate personal protective equipment (PPE) such as gloves and goggles to protect yourself from potential hazards like electrical shocks or sharp edges.


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