and mineral oils

which is essential for maintaining the operational integrity of sensitive bimetal sensing elements

018" diameter aperture

provided the stem is not excessively pitted

This switch mounts directly to the burner box

White-Rodgers 90-291Q Fan Relay and mineral oilsThe White Rodgers 90 291Q is a technical grade HVAC fan relay designed for switching single or two speed fan motors, solenoids, and resistive loads in commercial and residential systems. As a Type 84 enclosed relay, it features a Single Pole Normally Open (SPNO) configuration, making it a standard choice for 120V fan relay replacements where reliability is non negotiable. The 120V AC coil operates at a nominal 25 mA with a DC resistance of 2,000 Ohms,