Greenheck Fan Comprehensive Guide to Greenheck Backdraft Dampers and Motorized Damper Solutions

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.

Damper Type		Description	Flush Exterior	Flush Interior
Exhaust - Gravity or Motorized¹		WD-320 and WD-300	Exhaust backdraft dampers	For applications where the
		exhaust dampers are	are Model WD-320, which	mounting flange is required
		available as either gravity	has the prepunched	on the inlet end of the
		operated or motorized	mounting flange located	damper (so that the damper
			on the outlet end of the	projects to the exterior), the
			damper for a flush exterior	Model WD-300 is available.
Airflow	Airflow		appearance.

Wall Housing Installation		Wall Installation	Model WD-320 shown
Supply – Gravity²			• WD-430 and WD-420		• Model WD-430 has a		• Model WD-420 is for
				intake dampers are		prepunched mounting	applications where a
				only available as gravity		flange located on the inlet	prepunched mounting
				operated		end of the damper for a	flange is required on the
			•	Galvanized steel frame		flush exterior appearance	outlet end of damper (so
							the damper projects to
	Airflow	Airflow		and aluminum blades	•	Flange on intake
							the exterior)
							• Flange on discharge
Wall Housing Installation	Wall Installation		Model WD-430 shown
Supply - Motorized³			• WD-220 and WD-210		• Model WD-220 has a		• Model WD-210 is for
				intake dampers are only		prepunched mounting	applications where
				available as motorized		flange located on the inlet	a mounting flange is
			•	Galvanized steel frame		end of the damper for a	required on the outlet end
						flush exterior appearance	of the damper (so that
				and aluminum blades
	Airflow						the damper projects to
		Airflow
					•	Flange located opposite	the exterior)
						of motor side of the	• Flange located on motor
						damper	side of the damper

Wall Housing Installation Wall Installation

Model WD-220 shown

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.

Damper Type	Description	Flush Exterior	Flush Interior
Exhaust or Supply - Motorized	Model VCD-20- Standard leakage	The VCD damper has the	N/A
	Model VCD-23 - Low leakage	parallel blade set-up and
		a prepunched mounting
	– This damper has blade and jamb
		flange that provides a flush
	seals for minimal leakage when
		exterior appearance.
	closed.
Airflow	Model VCD-34- Insulated low
	leakage – This damper has blade
	and jamb seals for minimal
Airflow	leakage when closed. Blades are
	constructed with 1⁄2 in. (13 mm)
	polystyrene insulation between two
Wall Housing Installation Wall Installation	galvanized steel skins.

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.

³Model 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. 11