Greenheck BR Series - Counterweight Adjustment (469420) - Manual (Page 4)

Counterbalance Adjustment for BR-4X Series: Horizontal mount - vertical Down
Airflow
Figure 7 details the components of a typical adjustable counterweight assembly. Dampers
with a short height may have a different style blade and a trimmed mounting bracket. The
adjustment procedure is the same for both styles of blades.
The blade edge counterweight (Figure 7) is factory set for the specified start open pressure.
For vertical down airflow, minor adjustments can be made in the adjustable counterweight
assembly. If the desired change is greater than the capability of the adjustable
counterweight assembly, then changes to the blade edge weight would be required.
Consult factory for assistance in adjusting blade edge weight.
When adjusting the counterbalance weights, you will need to adjust the full open pressure
and start open pressure. Both steps will need to be done.
Adjusting full Open Pressure and Closing force
Adjusting the closing force will also affect the full open pressure. Figure 7 shows the blade
in the full open position. Additional weights can be added to increase the closing force.
Removal or trimming of weights will reduce the closing force. After adjustment, verify
blades close under no airflow from the full open position. Increase the closing force if the
blades fail to close.
Adjusting Start Open Pressure
When the blades are in the closed position, the adjustable weights are used for the start open pressure of the damper. Sliding
the weights toward the blade edge counterweight will increase the start open pressure and sliding the weights toward the
blade seal will decrease pressure (Figure 8).
If sliding the weights to the furthest left position (toward the blade edge counterweight) does not provide a high enough start
open pressure, additional weight to the blade edge counterweight would be required. Consult factory with desired start open
pressure.
Dampers are factory adjusted to the start open pressure, based upon your order, for the specified flow direction. Typically,
a minimum of one weight plate will be used to keep blades closed, although only the mounting bracket may be sufficient for
small damper sizes. Consult factory if an elevated start open pressure is required.
final Adjustment Check
After adjusting the counterweights, verify that no interference occurs between the counterweights and the adjacent blades.
If any interference, adjust counterweights. Also verify that the damper blades close under no airflow from the full open, 1/2
open, and 1/4 open positions. If blades do not close, adjust weights as required.
Blade Edge
Counterweight
Counterbalance
Weights
Counterweight
Adjustment
Bracket
Increases
Open Pressure Decreases
Open Pressure
Figure 7 - Adjustable counterweight
assembly detail
Blade Edge
Counterweight
Counterbalance
Weights
Counterweight
Adjustment
Bracket
Increases
Open Pressure Decreases
Open Pressure
Figure 8: Counterweight adjustment for start open pressure.
Blade is shown in full close position.
469420• BR Series Rev. 2, October 2012 Copyright 2012 © Greenheck Fan Corporation
As a result of our commitment to continuous improvement, Greenheck reserves the right to change
specifications without notice.
Specific Greenheck product warranties are located on greenheck.com within the product area tabs and in
the Library under Warranties.
®
Phone: (715) 359-6171 • Fax: (715) 355-2399 • E-mail: [email protected] • Website: www.greenheck.com
Our Commitment