Aprilaire 4640 Scale Control Insert L99H008 Enables stable system operation in

Enables stable system operation in low ambient cooling conditions down to 0°F

this 115V/230V 3450 RPM motor delivers the torque and mechanical precision required for optimal system static pressure and CFM performance

This internally equalized valve is critical for preventing compressor short-cycling

this model is specifically designed for hot water heating systems

Aprilaire 4640 Scale Control Insert L99H008 Enables stable system operation inMaintaining your whole home humidification system requires precision engineered components like the Aprilaire 4640 Scale Control Insert. This genuine Aprilaire replacement part is specifically designed to encase the humidifier water panel, serving as a structural U shaped insert that guides water flow and manages mineral accumulation. Constructed from durable, heat resistant polypropylene, the 4640 insert effectively captures heavy scale buildup and