Easily installed in standard 2-1/2"D vertically-installed junction box. Spring-wound mechanical dial, open in the off position to permit fan operation from standard pull switch when not in use. Operates with 1 HP motors and standard household current of 115 Volts, 60 Hz, single phase. Includes durable plastic knob and wall plate marked in 2-hour increments. Equipped with continuous-on hold feature.
Injection molded frame with smooth aluminum louvers that automatically open when fan turns on, and close when fan turns off to keep out air, insects, and dust. Balanced shutters for complete automatic service-free operation. Installs centered on joist with 18" or 24" centers with 2 cut openings, 1 on each side of center joist per shutter model. 35-3/4"L x 30-1/4"W OD, 33-3/4"L x 28-1/4" W opening. White enamel finish. Replacement shutter for Master Flow 30BWHFS (whole house fan).