Comprehensive Guide: Gas Furnace Inducer Motor Not Starting
If your gas furnace’s inducer motor is not starting, it can be a frustrating issue that requires troubleshooting. This comprehensive guide will walk you through the common causes, symptoms, and step-by-step diagnosis instructions to help you get your furnace back up and running.
What Causes the Inducer Motor to Not Start?
The inducer motor is a critical component in a gas furnace, responsible for drawing air through the combustion chamber and venting the exhaust. When the inducer motor fails to start, it can prevent the furnace from igniting and producing heat. Some of the most common causes for an inducer motor not starting include:
- Seized Shaft: The motor’s shaft can seize due to wear and tear or lack of maintenance, preventing the motor from turning on.
- Open Winding: The electrical winding inside the motor can become open, causing the motor to not function.
- Bad Capacitor: A faulty capacitor can prevent the motor from receiving the necessary starting voltage, leading to intermittent or no start.
- Pressure Switch Issues: A faulty pressure switch or vacuum leaks can prevent the motor from starting or staying on.
- Control Board Failure: If the control board is not sending power to the inducer motor, it may be defective.
How to Troubleshoot an Inducer Motor That’s Not Starting?
To troubleshoot an inducer motor that is not starting, follow these steps:
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Check Power Supply: Ensure that the thermostat is calling for heat and that there is 24VAC at the W terminal. Also, verify that 120VAC is being supplied to the inducer motor from the control board.
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Inspect Wiring and Connections: Check for any loose or damaged wiring connections between the control board and the inducer motor. Ensure that all connections are secure and free from corrosion.
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Test the Capacitor: If the inducer motor uses a capacitor, test it for proper function. A bad capacitor can prevent the motor from starting.
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Check the Pressure Switch: The pressure switch must be closed for the inducer motor to start. Check for vacuum leaks or a faulty pressure switch by sucking on the hose connected to it.
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Inspect the Control Board: If the control board is not sending power to the inducer motor, it may be defective. Check for any signs of physical damage or burn marks on the board.
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Examine the Inducer Motor: Check the motor for physical damage, such as a seized shaft or open winding, which can prevent it from starting. Listen for unusual noises that may indicate a failing motor.
When Should You Replace the Inducer Motor?
If the troubleshooting steps do not resolve the issue, it may be necessary to replace the inducer motor. Some signs that the motor needs to be replaced include:
- Noisy operation, such as rattling, clanking, or chattering
- Intermittent or inconsistent operation
- Excessive heat or overheating
- Failure to start when the thermostat calls for heat
When replacing the inducer motor, ensure that the replacement is compatible with your gas furnace model. The cost of the motor can vary from $50 to $200, and the labor cost can range from $100 to $300, depending on the complexity of the job and the technician’s rates.
By following the steps outlined in this comprehensive guide, you can effectively troubleshoot and address the issue of a gas furnace inducer motor not starting, helping to restore the proper operation of your heating system.
Reference:
- YouTube: Inducer Motor Not Coming On – How to Check It
- DoItYourself.com: Inducer motor not starting up
- Reddit: Inducer turns on but no heat. Gas furnace part 2
