Overview
The Ashcroft B424B is a general-purpose pressure switch designed for industrial, OEM, and hydraulic system applications. Rated 0–200 PSI with NEMA 4X enclosure protection, this switch provides long cycle life and dependable performance for pressure control, shutdown, and alarm operations across chemical plants, power generation, manufacturing, and water treatment facilities.
Key Features
- SPDT (Single Pole Double Throw) snap-action switch element
- NEMA 4X watertight enclosure meets NEMA 3, 4, 4X, 13 and IP66 standards
- Adjustable setpoints from 15–100% of range with internal locking screw
- Buna-N actuator seal for corrosion resistance
- Factory preset or field-adjustable to your specifications
- Wide selection of wetted materials for specialty applications
Technical Specifications
- Pressure Range: 0–200 PSI
- Switch Type: SPDT snap action
- Electrical Rating: 15A 125/250/480 VAC; 1/2A 125 VDC; 1/4A 250 VDC; 6A 30 VDC
- Port Connection: 1/4″ NPT
- Enclosure Rating: NEMA 4X (Stainless Steel)
- Actuator Seal: Buna-N
- Process Temperature Range: 0° to 150°F (–17° to 65°C)
- Ambient Temperature Range: –20° to 150°F (–29° to 65°C)
- Setpoint Accuracy: ±1% of nominal range (factory set)
- Deadband: Fixed or limited adjustable
Typical Applications
- Offshore oil rigs and petrochemical plants
- Boiler and burner controls
- Pump and compressor shutdown protection
- Hydraulic and lubrication system monitoring
- Pulp, paper, and steel mill operations
- Water and sewage treatment facilities
- Food processing equipment
- Heating, ventilation, and air-conditioning systems
Compatibility & Replacements
Compatible With
- Industrial PLC and automation control systems
- Pressure monitoring and alarm circuits (120 VAC, 240 VAC, 480 VAC control)
- Hydraulic and pneumatic systems (0–200 PSI)
- OEM equipment requiring SPDT pressure detection
- Systems meeting NEMA 4X / IP66 environmental protection requirements
Replaces / Drop-In Replacement For
The B424B is part of the Ashcroft B-Series NEMA 4X line. Verify compatibility with your system integrator before ordering replacement units, as interchangeability depends on port type, pressure rating, switch element, and electrical specifications.
Works With
- Allen-Bradley PLC control circuits
- Siemens automation systems
- Mitsubishi industrial controllers
- EtherNet/IP and PROFINET networked systems (via interface modules)
- Process control and SCADA platforms
- Boiler burner management systems (BMS)
- Alarm and shutdown relay circuits






















