Greenheck SP-A390-QD Ceiling Exhaust Fan 30067439-890 The included 2-wire ventilation damper

The included 2-wire ventilation damper uses a spring-return mechanism

Enhanced System Protection: Minimizes thermal stress on heat strips and prevents premature wear on fan relays and contactors

or the control board throwing a "pressure switch stuck open" or "stuck closed" fault code

or a high differential pressure exceeding the MOPD

Key Benefits for Technicians: Precise Thermal Calibration: Fixed 150°F cut-out and 45°F reset differential ensures accurate furnace over-temperature protection

Greenheck SP-A390-QD Ceiling Exhaust Fan 30067439-890 The included 2-wire ventilation damperThe Greenheck SP A390 QD is a professional grade ceiling exhaust fan engineered for high performance air evacuation in commercial and multi family residential environments. This direct drive unit delivers a versatile airflow range of 279 to 410 CFM, making it a reliable solution for maintaining air quality in large restrooms and clean air applications. Constructed with a galvanized steel housing and lined with acoustic insulation, the SP A390 QD is