Series BB Bourdon Tube Differential Pressure Switches Stainless steel bourdon tubes, adjustable deadband, high pressure Welded stainless steel bourdon tubes reduce chance of leakage, (even in the event of fire), in Model BB Differential Pressure Switches. Units are ideal for checking differential pressure (head) across high pressure pumps and filters. Hermetically sealed mercury wetted contacts help ensure reliable operations. Extra sensitive (fixed deadband) unites are available on special order, as are weather-proof and explosion-proof enclosures. PHYSICAL DATA Temperature Limits:   -10 to 180°F. (-23 to 82.2°C). Pressure Connections:   ¼" NPT Male, except range 15S and 16S are ½" NPT male Electrical Rating:   5A @ 120VAC., 2.5A @ 240VAC Conduit Opening:   ½" conduit Wiring Connections:   Two screw type Circuit Type:   SPST. Model BB-521-3-XX closes on increase of differential pressure. For circuit to open on increase of differential pressure, specify Model No. BB-521-2-XX Set Point Adjustment:   Thumbwheel Housing:   Painted steel with transparent cover Bourdon Tube:   Type 403 stainless steel (TYPE 316SS available on special order) Weight:   4 lbs. (1.8 kg) Installation:   Must be vertical FACTORY STOCKED MODELS Model Operating Range PSIG Differential range PSID Min./Max. Deadband PSIG BB-521-3-6S BB521-3-8S BB521-3-9S BB521-3-10S BB521-3-11S BB521-3-12S BB521-3-13S BB521-3-15S BB521-3-16S 5-100 10-200 10-300 25-600 50-1000 100-1500 300-2500 500-5000 1000-8000 0-40 0-120 0-180 0-360 0-600 0-900 0-1500 0-3000 0-5000 3/40 4/120 6/80 15/360 20/600 40/900 50/1500 125/3000 500/5000 Maximum pressure not to exceed maximum adjustable operating pressure range. SUGGESTED SPECIFICATIONS Differential pressure switches shall be operated by welded type 403 stainless steel bourdon tubes. No elastomeric or plastic O-rings, diaphragm or packing shall be used in pressure containment. Contacts shall be hermetically sealed and mercury wetted. Units shall be Mercoid Model No. BB (____).