Weil McLain 511 624 303 Pressure Switch Els PW 17895 Key Benefits for HVAC Professionals: Key Benefits for HVAC Professionals: Precise Timing Control: Features a factory calibrated thermal delay (1 60s ON 1 45s OFF) for smooth staging of electric furnace heating elements The internal assembly utilizes a nickel plated stem and a highly saturated nitrile paddle to ensure a bubble tight close off (ANSI Class IV leakage rating) even in demanding 15 psig steam environments 12" WC but the SPST switch terminals show no continuity Universal Barb Interface: The dual 1 4" barb connection accommodates standard pressure tubing for quick integration into existing pneumatic lines