Counterbalance Adjustment for EM/ES-
10, 11, and 12 Models: Horizontal Mount-
Vertical Airflow Up
There are two different adjustments that can be made:
Adjustment #1: affects the balance of the
blades in the closed position along with a small
change to the open position balance.
Adjustment #2: affects the balance of the
blades in the open position. Use this adjustment
method if the damper blades do not achieve full
open position under airflow and you want them
to open further or all the way.
If the airflow through the damper is light and the
blades only slightly move from the closed position,
then Adjustment #1 is required. If the airflow through
the damper is light and the blades do not reach full
open position then Adjustment #2 may be excessive
or Adjustment #1 may need to be increased or both
adjustments may need to be addressed.
Adjustment #1:Balance the Blades in the Closed
Position
Moving the weight along the length of the mounting
bracket slot will affect the full closed balance of the
blade assembly. Moving the weights further away from
the blade pivot point will cause the blades to become
more balanced so that at some point, and with enough
weight, the blades would remain open without air
pressure being applied. Care must be taken to ensure
that when the weights are moved away from the
blade pivot point the weights will not interfere with the
adjacent blade when the blades close. Moving some
of the weights back towards the blade pivot point will
allow the blades to return to the closed position.
Adjustment #2: Balance the Blades in the Open
Position
The damper is factory assembled with the
counterbalance assembly installed such that, the
counterbalance weights and bracket are positioned at
a slight angle to the surface of the blade. This angle
will position the weights such that they will provide
a slight load that will cause the blades to rotate from
the full open position toward the closed position.
If for some reason the blades remain in the open
position then you will need to increase this load. To
do this the counterweight mounting brackets should
be bent further away from the blade surface. Bending
the counterweight mounting brackets will move the
counterweight stack away from the blade surface and
therefore the torsion effect will force the blades to start
closing. This adjustment should be performed in small
increments to each weight bracket.
Counterbalance Adjustment for EM/ES-
40, 41, 42: Horizontal Mount - Vertical
Airflow Down
There are two different adjustments that can be made:
Adjustment #1: affects the balance of the
blades in the closed position along with a small
change to the open position balance.
Adjustment #2: affects the balance of the
blades in the open position. Use this adjustment
method if the damper blades do not achieve full
open position under airflow and you want them
to open further or all the way.
If the airflow through the damper is light and the blades
only slightly move from the closed position, then
Adjustment #1 is required.
Adjustment #1:Balance the Blades in the Closed
Position
Moving the weight along the length of the mounting
bracket slot will affect the full closed balance of the
blade assembly. Moving the weights closer to the
blade pivot point will cause the blades to become less
balanced so that at some point the blades would fall
open. Care must be taken to ensure that when the
weights are moved outward from the blade pivot point
the weights will not interfere with the adjacent blade
when the blades close. Moving some of the weights
back towards the blade pivot point will force the blades
to the close properly. If the damper blades do not close
completely and Adjustment #1 has been addressed,
then more weight is required.
ES EM GM Series
3
