MP100A motorpack
2
®
Installation Instructions
1. The MP-100A motor pack is designed for installation on model WD-100 series backdraft dampers only. When
properly installed, the damper will be horizontally mounted (air flow up) and the motor pack will be above the
damper.
2. Attach connection link(s) to the damper link using the #10 hardware along with the bronze bushing(s), see Detail
B. Use position “A” on most applications. Position “B” can be used on larger dampers when negative pressure
is present. The damper blades can be lifted to the open position to provide easier access when attaching the
connecting link(s) to the damper link. Tighten all fasteners.
Note:
Check that the connecting links are over the bushing(s) and not pinched between the end of the bushing
and the screw or damper link. As the blades are being closed, the linkage bolt that is used to attach the
connecting link to the damper link may interfere with damper blade bearing rail, causing the blades to remain
slightly open. To resolve this interference issue, using pliers, bend that area of the damper blade bearing rail
away from the bolt head until sufficient clearance is provided.
3. Attach the motor pack assembly to the damper frame with the
1
⁄
4
in. #10 screws and nuts provided. Assemble
the connecting link(s) to the actuator arm assembly using the hardware provided. The damper blades should
be closed during this connection. The angle between the connecting links and the actuator arm should be
as shown in Detail C with a slight tension on the spring. Tighten the fasteners between the connecting link
and the 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 the damper blades close completely when released.
Note:
The spring can be adjusted to provide more or less closing force. It is important not to use too much
spring tension; use just enough to help close the damper. Too much tension could impair damper opening.
4. 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).
5. 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-100A 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
