The 550 Series Heavy Duty Return Air Grille is styled to match the 150 and 250 Series Supply Grilles. The face blades are non-adjustable and available in either a horizontal (550HD-H) or vertical (550HD-V), factory set at either 0º or 45º, spaced on .750″ centers (with optional .500″ centers at an additional cost).
The same hollow air-foil blades used on the supply grilles are used on the return air grilles, and blades are reinforced from the back on 6″ – 8″ centers. The 550 Heavy Duty Return Air Grille has blade support to prevent damage, making them ideal for heavy duty applications.
Specify: Series S-44 Opposed Blade Damper to make return register. The S-44 OBD assures even distribution of air across the grille face, as well as positive volume control.