Product Overview

The WIKA PSM02 is a compact mechanical pressure switch designed for monitoring and controlling pressure in hydraulic, pneumatic and general machinery systems.

Part number 14078544 uses a diaphragm measuring element and provides an adjustable pressure range of 0.5–8 bar. Both the switching point and switching hysteresis can be adjusted to match the required alarm, shutdown or control function.

The switch operates mechanically and therefore does not require a separate power supply for pressure measurement. Its SPDT changeover contact can be connected as normally open or normally closed, depending on the control circuit.

Main Features

• Adjustable pressure range from 0.5 to 8 bar
• Adjustable switching hysteresis
• Compact screw-in construction
• SPDT changeover electrical contact
• Switching-point non-repeatability of ≤2% of span
• Maximum system pressure of 60 bar
• Standard G¼ B process connection
• DIN electrical connector
• Suitable for compressed air, neutral gases and compatible fluids
• Mechanical operation without a separate sensor power supply
• Suitable for alarm, control and equipment shutdown circuits
• Current standard product available through WIKA’s product range

Technical Specifications

Operating Principle

Pressure entering through the G¼ process connection acts on the internal diaphragm. When the adjusted pressure is reached, the mechanical mechanism operates the SPDT microswitch.

The contact can then be used to:

• Generate a high- or low-pressure alarm
• Stop a pump or compressor
• Start standby machinery
• Operate a control relay
• Provide an interlock signal
• Protect machinery against abnormal pressure

The reset point is determined by the adjusted switching hysteresis.

Marine and Industrial Applications

Although WIKA classifies this model primarily as an industrial pressure switch, it may be used in suitable non-class-critical auxiliary machinery applications when its materials, ratings and certification meet the project requirements.

Typical applications include:

• Hydraulic power units
• Pneumatic control systems
• Air compressors
• Pump control systems
• Lubricating-oil monitoring
• Cooling-water systems
• Machinery alarm panels
• Pressure-control skids
• Injection-moulding machinery
• Mobile hydraulic equipment
• General plant and machinery construction

Common Replacement Requirements

This pressure switch may require replacement when:

• The switch point becomes unstable
• The contact fails to change state
• Pressure alarms operate intermittently
• The hysteresis becomes excessive
• The electrical connector becomes damaged
• Process leakage develops around the connection
• The diaphragm is affected by incompatible media
• The original model is unavailable and a compatible replacement is required

Compatibility Warning

Part number 14078544 must not be selected only by its external appearance. Before replacement, confirm:

• Required pressure range
• Normal operating pressure
• High- or low-pressure switching function
• Required switch point
• Required reset differential or hysteresis
• Process connection and thread
• Electrical contact arrangement
• Voltage and current of the connected circuit
• Process-medium compatibility
• Required environmental and classification approvals

Do not use the product for oxygen service, aggressive chemicals, hazardous areas or safety-critical marine applications unless WIKA confirms the selected configuration is suitable.

Approvals and Compliance

The standard PSM02 part number 14078544 is presented by WIKA as an industrial product. Marine classification, hazardous-area approval and explosion-protection certification should not be claimed unless supported by the certificate supplied for the exact unit.