This SPST immersion-type controller manages both high-limit protection and low-limit circulator/burner cycling within a single

Smith boiler and pool heater models

Always verify your service manual's part list

this stainless steel power element restores factory-spec modulation without requiring a full valve body replacement

Is the TV-2 the same as the B4930 air vent

Siemens Industrial Controls 52BAK Contactor Block 318973-401 This SPST immersion-type controller managesThe Siemens Industrial Controls 52BAK is a precision engineered normally open (N O) contactor block designed for field level integration within professional motor control centers and automation panels. As a vital component for Siemens auxiliary contact expansion, this block allows technicians to implement critical interlocking, status signaling, and control logic modification without replacing the entire Siemens contactor assembly. Built for high duty