MP-310 Motor Pack2
Installation Instructions
1. The MP-310 motor pack is designed for installation on model WD-300 series backdraft dampers only.
2. For single panel damper, insert tab of motor bracket into the slot on the side of the frame. For dampers with center
bars, the tab of the motor bracket should be inserted into the slot on the bottom of the center bearing rail.
Position bracket over the two holes on the bottom of the frame and secure with the hardware provided.
3. Position the connecting link(s) on the second blade pivot from the bottom of the damper. Slip the connecting link
over the bushing and, with a needle nose pliers, bend the tab over to the position shown in Detail ‘A’. This will
hold the connecting link in place on the pivot.
4. Connect the actuator arm assembly to the connecting link using the provided hardware.
5. To adjust the actuator linkage assembly, pull back on the actuator arm assembly until a slight amount of tension
has been applied to the actuator spring. Tighten the fasteners between the connecting link and actuator arm
assembly. Fasteners should be placed as far apart as possible. This will provide greater stability to the linkage.
Operate the damper manually. Verify that the linkage fasteners do not interfere with any components of the
assembly and that the damper blades close completely when released. To increase spring tension raise the
spring up on the bracket. To decrease the spring tension lower the spring.
6. Actuators are supplied with junction box and cover. When wiring, make sure the supply voltage agrees with the
actuator voltage. On dual voltages motor packs, be sure to connect the proper motor leads for the correct
voltage and insulate any unused wire. The voltage of each specific model is indicated on a label that is affixed
to the actuator (see typical wiring diagrams).
7. If the damper fails to open properly, check for one of the following causes:
• Check for an ‘out of square’ or racked damper
• Check for mounting screws interfering with the blade and linkage rotation
• Spring tension too great
• Excessive voltage drop
• Excessive negative pressure in the building
If actuator fails to function:
• Check for correct voltage
• Check for proper wiring
Motor Pack Quantity
More than one motor pack may be required depending on damper size:
• On single panel dampers, the actuator is installed as shown on page 1 in the single panel view
• On double or triple panel dampers, the actuator(s) is installed as shown on page 1 in the multiple panel view.
Actuator Specifications
MP-310 motor pack uses a single phase shaded pole stall type impedance protected electric actuators and are
supplied in various voltages (see chart). For 277, 380, 575, or 600 volt operation a transformer and 120V motor pack
is required.
Motor Packs Stall Amps Spec ID#
24V (50/60 Hz) .66 G24
110 - 120V
(50/60 Hz) .15 G110-240
208 - 240V
(50/60 Hz) .07 G110-240
460V (60 Hz) .041 G460
