Lochinvar & A.O. Smith 100208391 Pressure Switch 322057-301 the T-4000-3139 is a blank

the T-4000-3139 is a blank "no-window" model designed for concealed applications where temperature readings and setpoint adjustments are managed by authorized technicians only

ensuring the branch circuit meets NEC requirements for HVAC electric heater kits

Key Benefits Dual-Size Versatility: Includes both small and medium plates to cover varying footprint sizes when swapping legacy hardware

ensuring quiet operation and preventing water hammer in the piping

it ensures reliable positioning and fail-safe performance during pneumatic signal loss

Lochinvar & A.O. Smith 100208391 Pressure Switch 322057-301 the T-4000-3139 is a blankThe Lochinvar & A. O. Smith 100208391 Pressure Switch is a mission critical safety component designed for precise pressure monitoring within high efficiency boilers and water heaters. Engineered to meet rigorous OEM specifications, this 0. 21" W. C. air pressure switch functions as a blower prover, ensuring the combustion blower is generating sufficient airflow before allowing the ignition sequence to proceed. By supervising the differential pressure