INSTALLATION: CAUTION - Disconnect power supply before connecting motor wiring to prevent electrical shock or equipment damage. 1.Using a 1/8” hex wrench loosen the motor coupling from the blade shaft and remove the existing motor assembly. 2.Ensure that the damper blades are in the correct installation position: Damper attached to zone control system is normally open - make sure damper is in the open position. Damper attached to thermostat or switch is normally closed - make sure damper is in the closed position 3.Loosen the set screw on the motor collar. 4.Place the actuator onto the damper shaft and insert the anti-rotation pin into the anti-rotation pin hole. If the damper shaft is a tight fit in the coupling, you can use sandpaper to smooth the damper shaft, which will allow you to fit the damper shaft into the coupler. 5.Double check that your damper blade and shaft are in the correct installation position for your application, then lock the collar onto the damper shaft by tightening the set screw on the collar. 6.Reconnect the motor wiring. Since these are AC motors, there is no polarity and either of the motor wires may be used in either position - orange and yellow wires are provided to match the original motor wires.