and 40 represents the differential (140°F minus 40°F equals a 100°F reset point)

While universal switches exist

Standardized 3-Inch Insertion: Allows for rapid installation into existing mounting brackets with a secure 3-inch probe depth

Common failures involve erratic resistance readings leading to short-cycling or the unit failing to enter defrost mode properly

Built for durability and precise calibration

Schneider Electric (Erie) VT2221 Valve Body and 40 represents the differentialThe Schneider Electric (Erie) VT2221 Valve Body is a professional grade solution for precise on off flow control in closed hydronic systems. This 1 2" NPT zone valve is engineered as a two way normally closed component, featuring a 1. 0 Cv flow coefficient and a rugged forged brass build. Designed for seamless integration with Erie PopTop actuators, the VT2221 utilizes a "pop top" quick release mechanism that allows for tool free actuator removal,