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Square galvanised steel frame with aluminum damper panel, 17 by 17 inches, 4.5 inches deep

Dayton

Dayton 4HX65 Roof Mount Damper 17 in

SKU CH-CJD6-HWD4Y

Aluminium back-draft damper with a 17 in square frame and 1.1 sq ft free area for roof-mounted exhaust

  • TypeRoof Mount, Exhaust
  • Fits 12 in fan diameter for direct compatibility
  • 17 in square frame matches 14 1/2 in rough opening
  • 2000 fpm maximum air velocity handles high flow
  • 1 sq ft free area reduces airflow restriction
  • Galvanized steel frame with aluminum panels resists corrosion

Product Identity

The Dayton 4HX65 is a 17 in aluminium backdraft damper designed for roof-mounted exhaust applications. It fits a 12 in fan and installs into a square rough opening measuring 14 1/2 in by 14 1/2 in. The unit provides 1.1 sq ft of free area for airflow management.

Thermals Noise Power

Galvanised steel frame construction resists corrosion in outdoor exhaust environments. Gravity-operated panels open automatically under airflow up to 2000 fpm and close when the fan stops, preventing backdraft without powered actuators. The 20 ga frame thickness and 2 in frame depth maintain structural rigidity during operation.

Upgrade Context

This damper replaces worn or missing backdraft protection on existing roof-mounted exhaust fans up to 12 in diameter. The upgrade is worthwhile when an installation lacks automatic closure, allowing weather ingress or thermal loss when the fan is off. It is not suited for ducted supply applications or round duct connections.

Highlights

  • Fits 12 in fan diameter for direct compatibility
  • 17 in square frame matches 14 1/2 in rough opening
  • 2000 fpm maximum air velocity handles high flow
  • 1 sq ft free area reduces airflow restriction
  • Galvanized steel frame with aluminum panels resists corrosion

Specifications

BrandDAYTON
TypeRoof Mount, Exhaust

Questions about this item

How do I install the Dayton 4HX65 damper and what step is often missed?

Mount the 17 in square frame into a 15 1/2 in rough opening, secure the galvanized steel frame, and ensure the single aluminum panel swings freely outward — the step often missed is confirming the 2 in frame depth clears the roof curb.

What maintenance will the Dayton 4HX65 damper need later?

Inspect the aluminum backdraft panel seasonally for debris buildup and verify the hinge moves freely; the galvanized steel frame resists corrosion, so no coating renewal is required under normal rooftop exposure.

What is the first limit reached under sustained airflow on the Dayton 4HX65?

The 2000 fpm maximum air velocity is the primary limit; exceeding it can cause panel flutter and reduced backdraft sealing across the 1.1 sq ft free area.

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