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Square galvanised steel frame, aluminium blades, no flange, horizontal mount

Dayton

Dayton 3HHN1 Backdraft Damper Horizontal 35-3/4 in Square

SKU CH-JHN1-YRTNV

Horizontal or vertical backdraft damper with a 35 3/4 inch square galvanised-steel frame and 8.2 sq ft free area

  • TypeNo Flange, Horizontal or Vertical Mount
  • Prevents unwanted backdraft with automatic gravity operation
  • Fits 36-inch square duct openings without flange
  • Galvanized steel frame withstands 1 in wc pressure
  • 2 sq ft free area allows high airflow
  • Aluminum blades handle 2250 fpm maximum velocity

Square Backdraft Damper for 36-Inch Ducts

The Dayton 3HHN1 is an aluminium backdraft damper built for 36-inch square ductwork. It installs horizontally or vertically without a flange, using a galvanised steel frame that is 20 gauge thick. A single panel covers the opening and allows air to flow in one direction only.

Mounts Directly in Rough Opening

The unit fits a 36-inch square rough opening and measures 35 3/4 inches high by 35 3/4 inches wide with a 4 1/2-inch depth. Its 2-inch frame depth seats inside the duct, leaving a free area of 8.2 square feet. No separate flange or adapter is required, so the damper occupies minimal duct length.

Suits Gravity-Relief and Low-Pressure Systems

Installers handling maximum air velocities of 2 250 fpm and pressures up to 1 inch water column will find the damper adequate. It is not suited for high-pressure duct networks, round duct connections, or applications that demand motorised actuation or multiple panels.

Highlights

  • Prevents unwanted backdraft with automatic gravity operation
  • Fits 36-inch square duct openings without flange
  • Galvanized steel frame withstands 1 in wc pressure
  • 2 sq ft free area allows high airflow
  • Aluminum blades handle 2250 fpm maximum velocity

Specifications

BrandDAYTON
TypeNo Flange, Horizontal or Vertical Mount

Questions about this item

What is the maximum air velocity the Dayton 3HHN1 damper can handle before airflow becomes a limiting factor?

The damper is rated for a maximum air velocity of 2250 fpm, which represents the upper limit for sustained airflow performance.

How much pressure drop does the damper create when installed in a horizontal duct run operating continuously?

The maximum pressure rating is 1 in wc, indicating the pressure differential the damper can withstand during all-day operation without excessive resistance.

What duct dimensions must already exist for this 35-3/4 inch square damper to fit properly?

A rough opening of 36 inches square is required, matching the nominal duct diameter of 36 inches for square duct installations.

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