ASHCROFT B4 Pressure Switch

The ASHCROFT B4 Pressure Switch delivers reliable pressure control for industrial and OEM applications. It supports pressure control, shutdown and alarm operations where long-cycle life and dependable switching matter.

This watertight Type 400 pressure switch suits many process and equipment applications. It offers factory-set or field-adjustable setpoints, multiple switch element choices, and actuator seal materials for different process conditions. In addition, special designs support NACE and fire-safe applications when the service requires more stringent materials or construction.

Westech Industrial supplies the ASHCROFT B4 Pressure Switch in Alberta and Saskatchewan. Our team can help confirm pressure range, diaphragm material, switch element, connection size and options. Westech can also support service needs, system upgrades and custom fabrication when the switch forms part of a larger control panel, analyzer package, skid or engineered solution.

ASHCROFT B4 Pressure Switch

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Description

Reliable Switching for Industrial Pressure Control

The ASHCROFT B4 Pressure Switch gives operators a dependable way to initiate control, shutdown or alarm actions. It suits applications where equipment protection and process consistency need a clear pressure setpoint. Because it offers factory-set or field-adjustable setpoints, teams can select the approach that best matches their maintenance and commissioning practices.

The switch generally allows setpoints between 15% and 100% of the nominal range on increasing pressure. This flexibility helps match the switch to the process without oversizing the range. As a result, users can improve setpoint performance and simplify selection.

Watertight Type 400 Enclosure

The B4 uses a Type 400 watertight enclosure for industrial service. It meets NEMA 3, 4, 4X, 13 and IP66 requirements, which helps protect the switch in outdoor or washdown-prone environments. The standard epoxy-coated aluminum housing provides a durable enclosure for common industrial installations.

This enclosure makes the ASHCROFT B4 Pressure Switch a strong fit for non-hazardous industrial locations that still need moisture and environmental protection. For hazardous area requirements, confirm whether another B-Series enclosure style better fits the application.

Broad Pressure Range and Material Options

The ASHCROFT B4 Pressure Switch supports vacuum, compound, low-pressure and pressure ranges up to 3000 psi. It also offers several actuator seal and diaphragm material options, including Buna-N, Viton™, Teflon™, stainless steel and Monel®. These choices help users match the switch to the process media and temperature conditions.

For more demanding service, welded actuator options and special designs can support fire-safe or NACE requirements. In addition, Ashcroft diaphragm seals can help protect the switch in severe services such as slurries or abrasive process fluids.

Switch Elements for Different Control Needs

The B4 offers a wide selection of switch elements. Options include narrow deadband, general purpose, hermetically sealed, low-level gold contacts, heavy-duty AC, heavy-duty DC, high-temperature, manual reset and dual switch configurations.

This range of choices helps match the switch to the electrical load, deadband needs and control strategy. For example, hermetically sealed contacts can add reliability in demanding environments. Dual switch elements can also support two switching actions from one pressure input.

Options for Installation and Documentation

The ASHCROFT B4 Pressure Switch supports several options that help simplify installation, documentation and project requirements. Available options include mounting brackets, terminal accessories, tagging, traceable calibration certificates, metric range labels, range scales and alternate pressure or electrical connections.

Westech can help review these options during selection. This step helps reduce ordering errors and ensures the switch fits the process, panel layout and site standards.

Applications

The ASHCROFT B4 Pressure Switch suits many industrial and OEM applications where pressure must trigger control, shutdown or alarm functions. It can support process equipment, utility systems and machinery that need reliable pressure monitoring.

  • Offshore oil rigs
  • Chemical and petrochemical plants
  • Pulp and paper mills
  • Steel mills
  • Power plants
  • Water and sewage treatment plants
  • Corrosive industrial environments
  • Pumps and compressors
  • Filters and washers
  • Degreasers and evaporators
  • Recovery systems
  • Food processing equipment
  • Reverse osmosis systems
  • Heat exchangers
  • Marine equipment
  • Textile machinery
  • Heating and air conditioning equipment

Documents

Ashcroft_B series switches_Spec sheet_June2026_Westech.pdf

Manufacturer info

A world where our customer’s people, processes and profits are never at risk because of the reliability of Ashcroft’s products and services.

http://ashcroft.com/

SPECS

Product:
ASHCROFT B4 Pressure Switch.
Switch Type:
Type 400 pressure switch.
Enclosure:
Watertight enclosure.
Enclosure Rating:
NEMA 3, 4, 4X, 13 and IP66.
Enclosure Material:
Epoxy-coated aluminum.
Setpoint:
Factory-set or field-adjustable.
Adjustable Setpoint Range:
Generally 15% to 100% of nominal range on increasing pressure.
Setpoint Repeatability:
±1% of full range (Additional setpoint shift of 1% of range per 50°F from a 70°F reference).
Electrical Output:
SPDT or DPDT.
Switch Element Options:
Narrow deadband, general purpose, hermetically sealed, low-level gold contacts, heavy-duty AC, heavy-duty DC, high-temperature, manual reset, variable deadband and dual switch elements.
Standard Pressure Connection:
¼ NPT female.
Optional Pressure Connections:
½ NPT female or ¼ NPT female and ½ NPT male combination.
Standard Electrical Termination:
¾ NPT female.
Optional Electrical Terminations:
½ NPT female or M20 x 1.5.
Ambient Temperature Range:
-20°F to 150°F, or -28°C to 65°C.
Diaphragm Materials:
Buna-N, Viton™, Teflon™, stainless steel or Monel®.
Process Temperature with Buna-N or Teflon™ Diaphragm:
0°F to 150°F.
Process Temperature with Viton™ Diaphragm:
20°F to 300°F.
Process Temperature with Stainless Steel or Monel® Diaphragm:
0°F to 300°F.
Pressure Ranges:
Vacuum and pressure ranges up to 3000 psi.
Available Special Designs:
NACE and fire-safe applications.
Approvals and Certifications:
UL E34743, CSA 55541, FM Limit Control and Steam Limit Control options, CE and UKCA.
Availability:
Alberta and Saskatchewan through Westech Industrial.

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PRODUCT FAQ's

What does the ASHCROFT B4 Pressure Switch do?
The ASHCROFT B4 Pressure Switch monitors pressure and triggers a switch action at a selected setpoint. Plants often use it for pressure control, shutdown or alarm operations.
Where should I use the B4 instead of the B7?
The B4 uses a watertight Type 400 enclosure. It suits non-hazardous locations that need environmental protection. The B7 supports explosion-proof applications, so confirm the area classification before selecting a model.
Can Westech help me choose the right B4 configuration?
Yes. Westech can help confirm the pressure range, diaphragm material, switch element, deadband, connection size and options. This support helps align the switch with your process and site requirements.
Can Westech include the B4 in a larger system?
Yes. Westech can support custom fabrication and integration needs. Our team can help incorporate pressure switches into control panels, analyzer packages, fabricated skids or other engineered solutions.
What pressure ranges does the B4 support?
The B4 supports vacuum, compound, low-pressure and pressure ranges up to 3000 psi. The correct range depends on the setpoint, process pressure and operating conditions
Are NACE and fire-safe designs available?
Yes. Special designs are available for NACE and fire-safe applications. Westech can help review these requirements during product selection.
What service support does Westech provide?
Westech can support product selection, troubleshooting, on-site evaluations, system upgrades and service-related discussions. This helps customers choose the right switch and maintain reliable operation.