Greenheck BR Series - Counterweight Adjustment (469420) - Manual (Page 3)

Counterbalance Adjustment for BR-1X Series: Horizontal mount - vertical Up Airflow
cont.......
If sliding the weights to the furthest left position (toward the blade seal) does not provide a high
enough start open pressure, additional weights can be added. In this case, the closing force will
also increase.
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 for
plate quantity and sizing 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.
Counterbalance Adjustment for BR-3X Series: vertical mount - Horizontal Airflow
Figure 5 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 5) is factory set and not intended for field adjustment.
For horizontal airflow, all adjustments should be made in the adjustable counterweight
assembly.
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 Start Open Pressure
When the blades are in the closed position (Figure 5), the adjustable weight are used for
the start open pressure of the damper. Additional weights can be added to increase start
open pressure and removal or trimming of weights will reduce start open pressure. After
adjustment, verify blades close under no airflow from the 1/4 open position. If the blades fail
to close, additional weight is required.
Adjusting full Open Pressure and Closing force
Adjusting the closing force will also affect the full open pressure. Figure 6 shows the blade in the full open position. If blades
hang open or more closing force is desired, slide weights toward the bottom of the bracket (Figure 6). If the blades close too
fast or less closing force is desired, move weights toward the top of the bracket (Figure 6).
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 for plate quantity and sizing 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.
Counterweight
Adjustment
Bracket
Counterbalance
Weights
Blade Edge
Counterweight
Damper
Blade
Figure 3 - Adjustable
counterweight assembly
detail
Increases Start
Open Pressure Decreases Start
Open Pressure
Figure 4: Counterweight adjustment for start open pressure. Blade is shown in
full close position
Blade Edge
Counterweight
Damper Blade
Counterbalance
Weights
Counterweight
Adjustment bracket
Figure 5 - Adjustable
counterweight assembly detail
Increases Closing
Force
Decreases Closing
Force
Bottom of
Bracket
Figure 6: Counterweight adjustment in the full open position