The factory setting is 0

reducing audible noise and mechanical wear on the motor bearings and shaft

Pressure Regulation: Maintains the necessary internal pressure differentials for consistent burner performance and ignition reliability

Robust Construction: Precision-machined 3/4" gas valve threads ensure leak-free installation in demanding environments

Maintenance-Free Operation: The conductive microfibers function with virtually zero friction and are unaffected by dirt

Aprilaire 4331 Water Distribution Tray 321894-708 The factory setting is 0The Aprilaire 4331 Water Distribution Tray is a critical component engineered to maintain the peak efficiency of your whole house humidifier. Designed specifically for the Aprilaire Model 400, Aprilaire 400A, and Aprilaire 400M series, this genuine OEM part ensures that water is evenly dispersed across the water panel. By utilizing a precision engineered humidifier scale control insert interface, the Aprilaire 4331 prevents uneven saturation and