Backdraft dampers, Volume control/heavy duty dampers – Greenheck Fan SE1 User Manual
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Backdraft Dampers
Used alone or in conjunction with the wall housing or wall collar, backdraft dampers are available for exhaust or supply 
configurations. Backdraft dampers are constructed with galvanized frames, aluminum blades and vinyl blade seals. 
Actuators are available in 24, 120, 208, 230 or 460 volts. Actuators for 50 cycle voltages are also available. Actuators for 
50 cycle voltages are also available.
Volume Control/Heavy Duty Dampers
Volume control dampers are available for exhaust or supply configurations and may be used alone or in conjunction 
with the wall housing or wall collar. Constructed with heavy galvanized steel frames and blades, model VCD dampers 
are designed to handle higher air volumes than the standard backdraft damper. Dampers are available in standard 
leakage (VCD-20), low leakage (VCD-23) and insulated low leakage (VCD-34) configurations. Actuators are available in 
24, 120, 208, 230 or 460 volts. Actuators for 50 
cycle voltages are also available.
¹ Model WD-320 and WD-300 are used with fans where the motor is 5 hp or less. For fans with motors larger than 5 hp, the Model GM-31 medium duty gravity backdraft damper or
the Model VCD heavy duty motorized backdraft dampers are required.
² Model WD-430 and WD-420 are used with fans where the motor is 5 hp or less. For fans with motors larger than 5 hp, the Model VCD heavy duty motorized backdraft dampers are
required.
³ Model WD-220 and WD-210 are used with fans where the motor is 3 hp or less. For fans with motors larger than 3 hp, the Model VCD heavy duty motorized backdraft damper is
required.
Note: Wall housing length increases by 6 inches (152 mm) when a heavy duty backdraft damper is specified.
Wall Housing Installation
Wall Installation
Airflow
Airflow
Damper Type
Description
Flush Exterior
Flush Interior
Exhaust or Supply - Motorized
Model VCD-20 - Standard leakage
Model VCD-23 - Low leakage 
– This damper has blade and jamb 
seals for minimal leakage when 
closed.
Model VCD-34 - Insulated low 
leakage – This damper has blade 
and jamb seals for minimal 
leakage when closed. Blades are 
constructed with 
1
⁄
2
in. (13 mm)
polystyrene insulation between two 
galvanized steel skins.
The VCD damper has the 
parallel blade set-up and 
a prepunched mounting 
flange that provides a flush 
exterior appearance.
N/A
Damper Type
Description
Flush Exterior
Flush Interior
Exhaust - Gravity or Motorized¹
WD-320 and WD-300 
exhaust dampers are 
available as either gravity 
operated or motorized
Exhaust backdraft dampers 
are Model WD-320, which 
has the prepunched 
mounting flange located 
on the outlet end of the 
damper for a flush exterior 
appearance.
For applications where the 
mounting flange is required 
on the inlet end of the 
damper (so that the damper 
projects to the exterior), the 
Model WD-300 is available.
Model WD-320 shown
Supply – Gravity²
• WD-430 and WD-420
intake dampers are 
only available as gravity 
operated
• Galvanized steel frame
and aluminum blades
• Model WD-430 has a
prepunched mounting 
flange located on the inlet 
end of the damper for a 
flush exterior appearance
• Flange on intake
• Model WD-420 is for
applications where a 
prepunched mounting 
flange is required on the 
outlet end of damper (so 
the damper projects to 
the exterior)
• Flange on discharge
Model WD-430 shown
Supply - Motorized³
• WD-220 and WD-210
intake dampers are only 
available as motorized
• Galvanized steel frame
and aluminum blades
• Model WD-220 has a
prepunched mounting 
flange located on the inlet 
end of the damper for a 
flush exterior appearance
• Flange located opposite
of motor side of the 
damper
• Model WD-210 is for
applications where 
a mounting flange is 
required on the outlet end 
of the damper (so that 
the damper projects to 
the exterior)
• Flange located on motor
side of the damper
Model WD-220 shown
Airflow
Airflow
Airflow
Airflow
Airflow
Airflow
Wall Installation
Wall Housing Installation
Wall Installation
Wall Housing Installation
Wall Installation
Wall Housing Installation