Aprilaire 4640 Scale Control Insert L99H008 Zero Leakage: Rated for bubble-tight

Zero Leakage: Rated for bubble-tight shut-off (ANSI Class VI)

it can replace any brand if the microfarad (30/2 MFD)

reducing harmonic vibration and bearing stress

this model is specifically designed for hot water heating systems

Aprilaire 4640 Scale Control Insert L99H008 Zero Leakage: Rated for bubble-tightMaintaining 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