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Square aluminum backdraft damper, wall-mount frame, 19.75 inches wide, 4.5 inches deep

Dayton

Dayton 5NKN4 Backdraft Damper Wall Mount 19.75 In Square

SKU CH-EYDF-MMYAJ

Aluminium back-draft damper for 16 in square ducts, 19.75 in frame with 1.7 sq ft free area and 2250 fpm rating

  • Product typeWall Mount, Supply
  • Aluminium frame resists corrosion for long service life
  • 7 sq ft free area allows high airflow capacity
  • Gravity operation needs no power or wiring
  • 2250 fpm maximum velocity handles strong drafts
  • 75 in square fits standard wall openings

Application & User

The Dayton 5NKN4 is a square backdraft damper built for wall-mounted supply installations. It fits a 16 in fan and a 17 1/2 in rough opening, making it suited for HVAC contractors and facility managers who need gravity-operated airflow control in square duct runs.

Sustained Operation

Aluminum frame construction at 0.1 in thickness resists deformation when air moves at velocities up to 2250 fpm. The single-panel design maintains a 1.7 sq ft free area through the 4.5 in deep frame, allowing consistent draft prevention without flutter during continuous fan cycles.

Installation Notes

The unit mounts directly into the prepared square opening with an overall height and width of 19.75 in. Installers should verify that the 1 5/8 in frame depth clears interior obstructions; no connection hardware is included, so appropriate fasteners for the wall substrate must be sourced separately.

How it compares

Measured against everything we stock in General Hardware & Accessories, at today’s prices. Recalculated every night.

Price $69.99
Pricier than about 80% of the 2,607 comparable items (median $18.99).

Specifications

Product
Brand nameDAYTON
Product typeWall Mount, Supply

Questions about this item

How loud is the 19.75 in square backdraft damper when air moves at 2250 fpm all day?

The aluminium blades open passively with airflow and close by gravity, so the unit adds no motor noise; only the rush of air through the 1.7 sq ft free area is heard.

What rough opening must I already have cut for the 19.75 in square frame to fit?

A 17 1/2 in square rough opening is required; the frame depth is 1 5/8 in and overall length 4 1/2 in, so allow that clearance behind the wall.

Will the 16 in fan diameter rating align with the 17 1/2 in rough opening on my existing duct?

Yes — the damper is sized for a 16 in fan, and the 17 1/2 in square rough opening provides the standard clearance for that fan size.

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