How to Test Your Furnace Blower Motor: A Comprehensive Guide

Your furnace blower motor is a crucial component of your HVAC system that distributes hot or cold air throughout your home. When it is not working correctly, you may experience problems like no air flow, hot or cold spots, or reduced energy efficiency. Testing your furnace blower motor can help you identify problems and take the necessary steps to fix them. In this comprehensive guide, we will cover everything you need to know about how to test your furnace blower motor.

Furnace Humming But Not Blowing

If your furnace is humming but not blowing, it may be a sign that your blower motor is malfunctioning. Before you jump to conclusions, you can perform a few tests to ensure that the problem is, in fact, with your blower motor. First, check your air filter to see if it is clogged, as this can cause your furnace to overheat and shut down. If that is not the issue, check the blower motor by turning the thermostat to the “fan on” setting. If the blower motor starts to run, then the problem is likely with your furnace’s heating system rather than the blower motor. If the blower motor does not turn on, however, then it is time to start troubleshooting.

How to Check Furnace Blower Motor

The first step in testing your furnace blower motor is to check the power supply. Turn off the power to your furnace by flipping the circuit breaker, and then locate the blower motor. Most furnaces have a removable panel that you can remove to access the blower motor easily. Check the wiring connections to ensure they are secure and not damaged, and use a multimeter to test the voltage of the power supply. If the power supply is correct, move on to testing the blower motor itself.

How to Test a 3 Speed Fan Motor

Some furnace blower motors have three speeds, and each speed requires its own set of tests. To test a three-speed fan motor, start by identifying the three wires that connect to the motor. Using a multimeter, measure the resistance between each wire to ensure there is no open circuit. Next, use the multimeter to test each wire’s voltage to ground to ensure that they are all getting power. Finally, test the motor’s windings by measuring the resistance between the motor’s common wire and each speed wire. If the resistance is correct for each speed, the motor is likely working correctly.

How to Test Furnace Blower Motor

To test your furnace blower motor, start by disconnecting the power supply and removing the motor from the furnace. Clean the motor and the housing thoroughly to ensure that dirt or debris is not causing the problem. Use a multimeter to test the resistance of the motor’s windings. You should measure the resistance between the common wire and each speed wire. The resistance should be within the manufacturer’s specifications. If the resistance is incorrect, then the motor may be damaged and require replacement. Finally, test the motor’s capacitance to ensure that it is within the manufacturer’s specifications.

Testing and Troubleshooting Your Furnace Blower Motor

Testing your furnace blower motor is an essential part of maintaining your HVAC system and ensuring that your home stays comfortable all year round. By following the steps outlined in this comprehensive guide, you can identify and fix problems with your furnace blower motor quickly and easily. Remember to always follow the manufacturer’s instructions and take appropriate safety precautions when testing or repairing your furnace blower motor. If you are not comfortable performing these tasks yourself, it is always best to contact a professional HVAC technician for help. With a little bit of knowledge and care, you can keep your furnace blower motor running smoothly for many years to come.

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