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Furnace Blower Motor

Fatima Rangwala Apr 29, 2019
The reason a furnace runs is because of the blower motor present in the whole construction. One needs to ensure that its working conditions are not hampered. So, if your furnace has not been working for quite sometime now, check the blower motor for problems.
A furnace blower motor is the basic component that powers the flow of air in a furnace. And since the efficacy of the furnace depends on the blower, the possibility of its failure will lead to furnace malfunctioning.
The first thing that comes to our mind when any sort of device malfunctions is to call for a repairman or a technician. Taking such an action or step can prove to be expensive, therefore, many people prefer to repair the device themselves.

Troubleshooting Tips

  • Switch off the main supply to the furnace and wait for the motor to stop spinning.
  • When everything stops, try to spin the motor with your bare hands. If it doesn't spin freely, gently oil the parts that connect the ports.
  • If things still look tough, check the motor wiring. Check for all the colored wires; red, black, white, at times, green. See if they are connected well.
  • After scrutinizing all of this, turn on the power supply. Also, turn on the fan connected at the thermostat to check the condition of the furnace blower motor.
  • Move the switch of the fan from an auto position to an 'on' position. In the auto mode the motor turns on by itself.
  • If the motor fails to gain speed, that's when the need of a replacement is warranted.

Replacement Instructions

Required Materials

  • Volt-ohm meter
  • A screwdriver
  • Needle-nose pliers
  • 3-in-1 Oil

Repairing Procedure

Step #1
Switch off the main power supply to the furnace and remove the motor main cover panel gently. You will have to unscrew all the fasteners and slowly lift the cover panel out of its position.
Step #2
As aforementioned in the troubleshooting slides, you will have to locate the spinning wheel and try to spin the same with your hands to check for its free rotary motion.
Step #3
Begin oiling the ports of the machine by using the 3-in-1 oil, and if still the blower refuses to rotate freely, it's time to read the next step.
Step #4
The refusal of the blower to move freely can be due to it being hot. Give the blower motor sometime to cool down and then check for the wire connections.
Step #5
The checking of the wire connections is important because due to a lot of tension and movement in the machine, wires tend to break easily.
Step #6
If you still see everything intact, something might be wrong with the motor capacitor. This is a square box-like device bearing two wires, and is located adjacent to the blower motor.
Step #7
Check for its working condition too. If you see oil leaking out from the device, this is where the catch is. You will need a capacitor replacement to be done.
Step #8
Use needle-nose pliers to detach all the wires and lead off from the capacitor terminals. Do it gently. Get hold of a volt-ohm meter and tune it to a voltage setting. Use one of its probes to test the terminals.
Step #9
After placing the probe you must see a reading going from zero to maximum capacity. If you see no such reading, the capacitor definitely needs to be replaced with a new one.
Step #10
You can get a replacement piece of a capacitor from any hardware store. Replace it back to the original place the way it was, and then switch the main supply of the furnace back on. Also set the thermostat in order to start the furnace. In spite of all these steps if still the motor doesn't spin, replace the old one with a new piece from the market.
Make a note that working around a furnace can be hazardous, and if you think you cannot handle this job on your own, don't hesitate to fetch technical help.