Control Damper
Products
Manual Balancing Dampers
Commercial Control Dampers
Industrial Control Dampers
Control Damper Training
Application
Control Dampers are an integral part of every HVAC
system. They are positioned manually or automatically to
control air volume and temperature throughout the air
handling system.
Basic Functions
• Volume Control - Regulates airflow.
• Temperature Control - Maintains desired temperature.
• Pressure Control - Maintains desired pressure. (uncommon)
Control Damper Training
Volume Control
• Branch Dampers
Regulates airflow and branches.
• Balancing Dampers
Limit flow down the duct or
through a device by holding
damper blades at a specific position (typically via a manual
locking quadrant).
• Fan Inlet/Outlet Dampers
Used to control flow rate to or from the fan.
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Temperature Control
Mixing Dampers
• Operate as a pair to maintain temperature.
• Simultaneously regulates two different air streams - each with
different incoming air temperature.
• Able to control air temperature and volume.
Basic Mixing Application
Basic System Design
Control Damper Training
Temperature Control
Face & Bypass/Multi-Zone Dampers
• Regulates face air (hot or cold) with bypass/return air to
maintain temperature.
• Arranged side-by-side, top-bottom, or at right angles.
Typical Side-by-Side Face & Bypass Application
Control Damper Training
Standard Construction
Control Dampers have different
designs and are constructed from a
variety of frames, blades, axles,
bearings, blade linkage and other
parts to suit the particular application
for that damper.
Flat
Hat Channel
Frames
‘U’ Channel
Flat
Hat Channel
‘U’ Channel
Flanged
Flanged
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Blades
• Flat, typically for single-blades
dampers, low pressure applications.
• Triple-V, economical. Low to
medium pressure applications.
3-V Blade
• Airfoil, lower pressure drop, medium
to high pressure applications.
Airfoil Blade
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Blade Action
Parallel
• All blades rotate together in the
same direction.
• Typically two-position control.
Opposed
• Adjacent blades rotate in opposite
directions.
• Balancing and modulating control.
Parallel
Opposed
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Axles
Attached to the damper blade and extend through the damper
frame to permit the blades to rotate.
• Various sizes, lengths, materials depending upon the
application.
Bearings
Pressed into the damper frame to permit easy rotating
Of the damper blade & shaft.
• Various types and materials depending upon
the application.
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Blade Linkage
Mechanism that connects the blades together.
• Concealed - hidden within the frame on
one side or the other or in rare cases,
both sides of the damper.
Concealed
Linkage
• Exposed - attached to the blade face.
Exposed
Linkage
Control Damper Training
Damper Drive Mechanism
Mechanism that drives (operates) - all the blades together.
Typically connected to one blade - Drive Blade.
• Direct Drive - typically a shaft
extending from one side of the damper
adjacent to the damper frame.
Direct Drive
• Jack Shaft - typically a shaft, offset
but connected to the drive blade,
extending past the side of the damperused mostly when connecting multiple
single-sectioned dampers together.
Jack Shaft
Control Damper Training
Optional Low Leakage Seals
• Stainless Steel Jamb Seals - positioned between the end of
the blades and the inside of the damper frame and blade edge
seals attached to the damper blades.
Optional Stainless Steel Construction
• Typically standard construction material is galvanized steel.
Most models have type 304 stainless steel (only), and a few
offer 316.
Control Damper Training
Design Basics
Manual Balancing
• Commonly found at duct branches and used to restrict
airflow in the branch to the desired level.
Commercial Control
• Most common type and widely used for volume and
temperature control.
Industrial
• Employed when the temperature, pressure, or velocity
exceed standard commercial damper limits. Units are
typically flange mounted directly to the duct or
fan housing.
Control Damper Training
Manual Balancing Dampers
Concealed
Operator
Used to control the flow of air to
meet a required volume,
temperature and/or pressure.
Cable Control
• Enables remote damper positioning
from within the occupied space.
• Available for round and square duct.
RCS-10
RCS-10R
Integral
Sleeve
Quadrant Control
• Quieter than diffuser mounted OBD.
• With or without integral sleeve.
• Requires access to set quadrant.
Hand
Quadrant
CD-10IS
CD-10
CD-10R
Control Damper Training
Commercial Control Dampers
Blade Type
• 3-V
Exposed
Linkage
Economical - Galvanized Steel
• Airfoil
Lower Pressure Drop
Galvanized Steel or Aluminum
• True-Round
3-V Blade
Airfoil Blade
True Round
CD-22R
Multi-Blade
Concealed
Linkage
Blade Action
• Parallel
- Blades move together in the same direction
- 2-position control
• Opposed
- Adjacent blades turn in opposite directions
- Balancing dampers and modulating control
Drive
Shaft
Integral
Sleeve
True Round
CD-25R
Single Blade
Integral Sleeve
Control Damper Training
Commercial Control Dampers
Multiple Sections
• Jackshaft
• Bracing - As required
• Face & Bypass
Vertical Blades
• Actuator/Quadrant Access
• Thrust Washers
Hat Channel
Frame
Drive
Shaft
Jackshaft
Note
H = Blade Length
H
Face & Bypass Dampers
Control Damper Training
Industrial Control Dampers
• Employed when temperature pressure or velocity exceeds
commercial damper limitations.
• Typically are flanged frame construction and mounted
directly to the duct or fan housing. Supplied approx. net I.D.
• Are controlled by a manual locking quadrant or by an electric
or pneumatic actuator. Actuators are external mount only.
• Actuators are normally, but not always larger in size (more
powerful - larger torque) than those used for Commercial
Control Dampers/
Actuators
Electric
CD-81R
CD-82
Pneumatic
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Industrial Control Dampers
Blade Type
• 3-V
• Airfoil (n/a for Pottorff)
• True Round
Channel Frame
Frame Type
• Channel
Concealed
Linkage
Continuous Blade
Axle
CD-81R
Control Damper Training
No-Sleeve vs. Sleeve
Side Plate
No-Sleeve Dampers
• 1/4” under nominal size
Side Plate
• 12” wide x 16 gauge
Sleeved Dampers
• 20 gauge sleeve = 1/8” under nominal
size, the thicker the sleeve the closer
the OD is to nominal size
• Optional Transitions: AR (round),
AO (oval), AF (Flange)
• Labor Saver - Ready to install
from factory
Damper with Side Plate
Damper with Sleeve
Control Damper Training
Actuators
Actuators control the position of the damper based on signals
from the: Building Automation System (BAS), Thermostats &
Controllers, Pressure Switches and Relays.
Electric Actuators
Location
• External or Internal
Electric
• 2-Position Spring
Return
• Modulating
• 24, 120, 230 VAC
Pneumatic
• 25 psi control signal
LMB24-SR (Belimo)
NF-120 (Belimo)
Pneumatic Actuators
331-4826 (Siemens)
331-2998 (Siemens)
Control Damper Training
Actuators
Actuator selection is based upon the ability of the actuator to
adequately open and close the damper and the amount of
torque the actuator can supply. This typically depends upon
the following:
• Overall damper size.
• Velocity of air through the damper.
• Static pressure against the damper.
• Damper blade type - parallel or opposed:
-Normally parallel bladed dampers require more torque
to open than opposed but require less torque to close
than opposed.
• Whether the damper has jamb seals or not.
Our dampers are typically rated at 2000fpm and 1” wg.
Control Damper Training
Actuators
Depending upon the damper design,
most actuators can be mounted either
internally or externally.
External mount actuators
typically require a side plate or a
sleeve to mount the actuator.
External Mount
Internal mounts actuators
normally require that the
damper has offset jack shafting.
Internal Mount
Control Damper Training
To determine the proper actuator for a damper.
Refer to our catalog sheet entitled Louver and Air Control Dampers, in the
Actuators and Accessories section.
1. Calculate the square footage of the damper; example,
48” w x 36” h = 12 square feet.
2. Choose type of actuator - example, 2-position, spring return, 120 volt,
no internal switch package.
3. Top left section of our catalog sheet see section 2-Position Spring Return,
and then see list of actuators under column entitled 120 VAC Model.
4. Determine if the damper has seals or not:
• If yes, use the last column and any actuator rated 12 square feet
or above (under 120 VAC) is acceptable i.e.
FSNF-120
NF-120
AF-120
Control Damper Training
5. From the list you would typically choose the most economical actuator.
6. If the damper has no seals, use the 2nd last column and follow the
same steps to determine the list of actuators.
Note: If the job site conditions are greater than 2,000 fpm and/or 1” wg,
contact the factory so we can calculate the requirements and quote
the proper actuator.
Control Damper Training
Other Options & Accessories
Low Leakage Seals
• Stainless steel jamb seal and PVC blade edge seal.
Locking Quadrants
• Allow the damper blade to be manually positioned and
locked in place to supply the desired air volume.
Flange Frame
• For flush mounting to equipment/wall.
304 Stainless Steel Construction
PI-50 Dual Position
Indicator Switch
• Provides damper “open” or
“closed” signal for fan
interlock.
SQ-315
LQ-560
Control Damper Training
Testing
Commercial Control Dampers must
function in the HVAC System so as to
not adversely affect it.
Dampers are tested in
accordance with AMCA 500-D.
Dampers are certified and labeled
In accordance with AMCA 511.
Control Damper Training
Test Samples
• Leakage: Max-Max, Min-Max, Max-Min.
• Pressure Drop: 12x12, 12x48, 48x12,
24x24, 36x36.
Leakage Rating
Maximum Allowed Leakage (cfm/ft2)
Class
@ 1 in.wg.
@ 4 in.wg.
1A
3
8
1
4
8
2
10
20
3
40
80
Pressure Drop
• Ducted Inlet & Outlet - AMCA 5.3
AMCA 5.3 – Ducted Inlet & Outlet
Lowest Pressure Drop
• Ducted Inlet Only - AMCA 5.2
• Plenum Mount - AMCA 5.5
Highest Pressure Drop
AMCA 5.2
Ducted Inlet
AMCA 5.5 –
Plenum Mount
Control Damper Training
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