Lochinvar & A.O. Smith 100148403 Limit Switch 319852-301 Manual Override Security: Requires a

Manual Override Security: Requires a physical reset by a technician

While the charcoal filter element may trap some residual fine particles

we recommend this specific OEM part to maintain the manufacturer's safety specifications

Precision Machined Bore: The 1 inch bore diameter ensures a tight tolerance fit to minimize shaft wobbling and dynamic imbalance

This 24Vac motorized 3-way valve actuator is an exact-fit replacement designed to mount directly onto the boiler's water trim assembly

Lochinvar & A.O. Smith 100148403 Limit Switch 319852-301 Manual Override Security: Requires aThe Lochinvar & A. O. Smith 100148403 Limit Switch is a critical OEM replacement part designed for high limit temperature protection in commercial water heaters, boilers, and pool heaters. This 175 degree high limit assembly monitors the heat exchanger or outlet water temperature, providing an essential safety cutoff to prevent thermal runaway and equipment damage. Engineered for HVAC systems requiring precise thermal regulation, the 100148403 ensures