How to Replace the Blower Motor in an Armstrong Heater System

Remove Blower Motor

• 1

  Turn off the circuit breaker that powers the Armstrong heater system. Some systems also have a separate switch near the unit that looks like a wall light switch. Turn the switch to “Off.”

• 2

  Remove the blower compartment cover from the unit. The blower compartment cover lifts up and away from the unit.

• 3

  Find the wires connecting to the blower motor. Cut the wires with a pair of wire strippers as close to the motor as possible to ensure you have plenty of wire to connect to the new motor.

• 4

  Loosen the two bolts securing the squirrel cage blower to the furnace with a wrench. The motor attaches to the side of the squirrel cage blower. The blower slides in a track and the two bolts secure the blower to the track. Once the bolts are loose, unthread them completely by hand.

• 5

  Grab the squirrel cage blower and pull it out of the Armstrong furnace. Place the squirrel cage on its side with the motor facing you. Remove the three bolts securing the motor mounting bracket to the squirrel cage housing with a socket wrench. Remove the screw securing the motor ground wire to the squirrel cage housing with a Phillips screwdriver.

• 6

  Turn the squirrel cage over so you have access to the inside of the blower wheel. Remove the square head bolt securing the blower motor shaft through the center collar of the blower wheel with a wrench. Tap the end of the blower shaft with a hammer to loosen the shaft from the collar. Flip the squirrel cage housing again and pull the motor and mounting bracket away from the squirrel cage housing.

• 7

  Loosen the bolt securing the mounting bracket around the motor with a wrench. Before slipping the bracket off the motor, check the location of the wires in relation to the bracket arms. Install the bracket onto the new motor with the wires of the new motor in the same position. Pull the mounting bracket off the motor.

Install New Motor

• 8

  Slide the mounting bracket over the new motor with the bracket legs pointing in the same direction as the motor shaft. Tighten the bracket securing bolt just enough to keep the bracket on the motor, but loose enough that you can move the bracket up or down if necessary.

• 9

  Position the motor through the back side of the squirrel cage. Insert the motor shaft through the collar of the blower wheel. Once the shaft protrudes from the collar by 1/2 inch, tighten the square securing bolt on the side of the collar with a wrench.

• 10

  Push the motor bracket down until the legs are against the squirrel cage housing. Align it with the mounting holes. Secure the bracket to the housing with the retaining bolts and tighten the bracket securing bolt around the motor housing.

• 11

  Pick up the squirrel cage and slide it back into the Armstrong heater system. Strip 1/2 inch of insulation from the ends of the furnace wires with wire strippers. Using the instruction manual that comes with the new motor, match the motor wires with the furnace wires. Twist the ends of the wires together with wire nuts. Position the wires so they won't interfere with the motor shaft or blower.

• 12

  Secure the squirrel cage to the furnace track with the two retaining bolts. Replace the blower compartment cover and turn on the circuit breaker to power the unit.