PRESSURE SWITCH

Pressure Switch

Pressure Switch

Blog Article

Pressure Switch – Comprehensive Guide


A pressure switch is an electromechanical device that monitors fluid or gas pressure and opens/closes an electrical contact at a preset pressure level. It is widely used in HVAC, industrial automation, hydraulic systems, and safety controls.






Key Features


1. Types of Pressure Switches




  • Mechanical Pressure Switch (Diaphragm/Piston-based, adjustable setpoints).




  • Electronic Pressure Switch (Digital display, programmable, higher accuracy).




  • Differential Pressure Switch (Measures pressure difference between two points).




  • Vacuum Pressure Switch (For negative pressure applications).




2. Common Configurations




  • SPST (Single-Pole, Single-Throw) – Normally Open (NO) or Normally Closed (NC).




  • SPDT (Single-Pole, Double-Throw) – Switches between two circuits.




  • DPDT (Double-Pole, Double-Throw) – Controls two independent circuits.




3. Pressure Range & Adjustment




  • Low Pressure (0–15 PSI) – HVAC, air compressors.




  • Medium Pressure (15–300 PSI) – Hydraulics, pumps.




  • High Pressure (300+ PSI) – Industrial machinery, oil/gas.




  • Adjustable Setpoint (Manual screw or digital calibration).




4. Electrical Ratings




  • Voltage: 24V DC, 120V AC, 240V AC.




  • Current: 5A–15A (check manufacturer specs).




5. Materials & Protection




  • Body: Brass, stainless steel, or plastic.




  • Sealing: IP65/IP67 (dust/waterproof).




  • Media Compatibility: Air, water, oil, refrigerants.







Applications


✔ HVAC Systems (Compressor cut-off, fan control).
✔ Water Pumps (Dry-run protection, tank level control).
✔ Industrial Automation (Hydraulic press safety cut-off).
✔ Air Compressors (Auto shut-off at max pressure).






Wiring & Installation


1. Basic Wiring (SPST-NO Example)




  • Terminal 1 → Power supply (L1).




  • Terminal 2 → Load (e.g., relay, motor starter).




  • Ground → Earth connection.




2. Differential Pressure Switch Wiring




  • Port A → High-pressure side.




  • Port B → Low-pressure side.




  • Contacts → Control circuit (NO/NC).







Top Brands & Models

































Brand Model Example Key Feature
Danfoss KP5 Adjustable range (0.2–8 bar), SPDT
SMChttps://store.unigulfsupply.com/product/pressure-switch/ ZSE30 Digital display, IP65
Honeywell PSE530 High accuracy, 4–20mA output
Schneider Electric Square D 9013 Heavy-duty, 300 PSI





Where to Buy?




  • Industrial Suppliers: RS Components, AutomationDirect, Grainger.




  • Online: Amazon, eBay (search for "pressure switch [PSI range]").



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