Lochinvar & A.O. Smith 100113144 Switch 321894-709 Optimized Oil Return: Includes a

Optimized Oil Return: Includes a protective screen and calibrated orifice to maintain lubrication without siphoning excess liquid

Technicians should verify 24V at the relay coil

eliminating the guesswork during field installation

The V-bolt design allows for rapid centering and tightening with a 10mm wrench

Lochinvar & A.O. Smith 100113144 Switch 321894-709 Optimized Oil Return: Includes aThe Lochinvar & A. O. Smith 100113144 Blower Prover Switch is a critical safety component designed for high efficiency water heaters and commercial boilers. As a direct OEM replacement for NS2 1333 01, this pressure switch (often referred to as an air pressure switch or draft prover switch) monitors the differential pressure created by the inducer motor. By verifying stable airflow, it ensures the sequence of operation proceeds to ignition safely.