Lochinvar & A.O. Smith 100113144 Switch 321894-709 which means the contacts close

which means the contacts close at 28°F to signal the defrost board and open again at 70°F once the coil is sufficiently warmed

Technicians should verify 24V at the relay coil

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

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

Lochinvar & A.O. Smith 100113144 Switch 321894-709 which means the contacts closeThe 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.