Overview
The Ashcroft B424V pressure switch is a field-proven, general-purpose device designed for industrial pressure monitoring and control across HVAC, refrigeration, and hydraulic applications. With a Single-Pole Double-Throw (SPDT) switching action and a fixed deadband, this compact, low-cost unit delivers precise, repeatable pressure-activated control. The 30–500 PSI range accommodates a wide spectrum of system requirements, from low-pressure HVAC monitoring to medium-pressure industrial hydraulic circuits.
Key Features
- Contact rating of 15 A @ 125/250 VAC with compact, low-cost construction
- 1/4″ NPT process connection for easy installation into standard piping and manifolds
- Viton seal for superior chemical resistance and compatibility with a wide range of refrigerants, oils, and process media
- NEMA 4X watertight enclosure rated for indoor and outdoor use — protects against dust, dirt, rain, splashing water, and corrosion
- SPDT output provides maximum wiring flexibility, allowing technicians to configure the switch for either normally-open or normally-closed operation without additional hardware
Technical Specifications
- Electrical Rating: 15 A @ 125/250/480 VAC; 1/2 A @ 125 VDC
- Pressure Range: 0–500 PSI
- Switching Action: Single-Pole Double-Throw (SPDT) with fixed deadband
- Process Connection: 1/4″ NPT male
- Actuator Seal Material: Viton
- Enclosure Rating: NEMA 3, 4, 4X, and 13
- Operating Temperature: –20 to +150 °F
- Deadband: Fixed (manufacturer-set)
Typical Applications
The Ashcroft B4 pressure switch is designed for use in virtually all industrial, OEM and hydraulic system applications, providing reliability and long-cycle life for pressure control, shutdown or alarm operations. Common uses include pump/compressor startup inhibit, system relief monitoring, boiler pressure control, refrigeration circuit protection, and hydraulic manifold integration.
Compatibility & Replacements
Compatible With
- Industrial hydraulic systems and mobile equipment
- HVAC and refrigeration circuits
- Pneumatic and compressed air applications
- Water treatment and pumping stations
- Boiler and burner control systems
Replaces / Drop-In Replacement For
The B424V is available in multiple pressure-range configurations (B424V-30, B424V-200, B424V-400, B424V-1000). Verify the specific pressure rating of your existing switch before ordering to ensure a true drop-in replacement. Consult the original equipment documentation or contact your system integrator for model interchangeability.
Works With
- Direct 24 VDC and 120 VAC control circuits
- PLC inputs and discrete I/O modules via relay interface
- Industrial automation systems requiring hardwired pressure monitoring
- Standard DIN-rail and panel-mount installations










