York 024-39397-001 Flow Switch 30067439-890 it functions as a primary

it functions as a primary operator for the 240V load side

Maintenance-Free Design: Brushless DC motor prevents stall-related failures and extends the operational lifecycle

Precise Sensing: High-accuracy NTC thermistor assembly ensures the controller accurately tracks boiler temperature for safety limit and circulator control

and L8C Upflow furnace models

York 024-39397-001 Flow Switch 30067439-890 it functions as a primaryThe York 024 39397 001 Flow Switch is a mission critical differential water pressure (DWP) control designed for high performance HVAC and chiller systems. Engineered as a 24V flow switch, this component monitors real time fluid movement to protect downstream equipment from dry run conditions, pump cavitation, and thermal overload. Rated for a 150# DWP (150 PSI) maximum operating pressure, it provides the robust durability required for industrial and