By integrating this boiler control module

Constructed with high-grade materials to withstand high-ambient combustion chamber temperatures

25" diameter fit for standard HVAC blower bearings

The kit includes a high-impact

Aprilaire 4640 Scale Control Insert 324846-701 By integrating this boiler controlMaintaining 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