Pressure Switches, Gauges and Flow Monitors
Pressure switches – mechanical, electronic, and ATEX versions for air, liquids, and gases
Pressure switches monitor the operating pressure in your system and switch an electrical contact at the set value – for control, signaling, or shutdown. STASTO offers mechanical diaphragm and piston versions, electronic pressure switches with digital display, high-pressure variants, vacuum switches, and ATEX versions for hazardous areas. Tell us the medium, pressure range, process connection, and switching capacity – we'll match you with the right series and variant.
Series 901.6 · 901.9 · PDS · HDS · ADS · PS48 · PS15 · Vacuum Switch 901.7
Why STASTO
Pressure switches from a single source – from millibar to high-pressure range
Mechanical or electronic, standard or ATEX version: the range is organized by series so you can pinpoint the right variant for your application.
From millibar to high-pressure range
The range spans from fine differentials in the millibar range (Series 901.6) through the classic compressed air range (Series 901.9, PDS, PS48) to high-pressure versions of Series HDS. Refer to the specific variant for setting range and overpressure safety.
Mechanical or electronic – your choice
Robust mechanical switches with changeover contact and adjustment scale, or electronic pressure switches with digital display and freely adjustable switching outputs (Series PS15, PS17). Both principles are offered as dedicated series.
EX versions as dedicated series
For hazardous areas, the EX variants 901.6-EX and 901.9-EX – and for vacuum applications 901.7-EX – are dedicated series, not a loose accessory feature. The specific Ex marking depends on the variant; the datasheet of the ordered version is binding.
Expert advice instead of browsing catalogues
Our technical sales team narrows down the right series based on medium, pressure range, switching differential, switching capacity and connection – including for special versions and replacement needs.
Guide
Choosing the Right Pressure Switch
Five criteria determine the right series: operating principle, setting range with reset differential, overpressure safety, electrical connection and materials.
Operating Principle and Switching Behavior
- Mechanical
- Operates without auxiliary power, switching a changeover contact directly via diaphragm or piston – the economical solution for robust standard tasks.
- Electronic
- Series PS15 and PS17 provide a digital display, two independently adjustable switching outputs and finer parameterizable switching logic.
- Setting range
- The switching point should ideally sit near the middle of the series' setting range, not at the edge.
- Reset differential (hysteresis)
- Determines the pressure at which the contact resets, preventing chattering during pressure fluctuations. Mechanical units have a fixed value depending on variant; electronic units are usually freely parameterizable.
- Overpressure safety
- Besides the setting range, the maximum permissible overpressure matters – for example during pressure surges, pump start-up or water hammer in liquid lines.
Electrical Connection and Installation
- Potential-free changeover contact
- Mechanical pressure switches output a potential-free signal and are mainly used as a control contact on contactors, PLCs, or motor protection relays.
- 230 V, 400 V, three-phase
- Direct load switching of a three-phase consumer, such as a compressor at 400 V, must be verified against the contact ratings of the variant; when in doubt, wire a contactor in between.
- ATEX connection ratings
- ATEX versions have significantly different, restricted permissible connection ratings – the datasheet of the variant is decisive.
- Materials
- Diaphragm material (NBR, FKM, PTFE) and media-wetted parts (brass, stainless steel) determine media compatibility.
- Process connection and ingress protection
- For external/internal thread, connector width, and ingress protection rating, consider your installation situation – an adapter can affect the switching characteristics due to dead volume.
Variants compared
Mechanical, Electronic, High-Pressure or ATEX?
The four designs differ in display, configurability and application environment. Specific setting ranges and connection values depend on the variant.
| 901.6 / 901.9 | PDS / PS48 | HDS | PS15 / PS17 | 901.6-EX / 901.9-EX | |
|---|---|---|---|---|---|
| Operating Principle | Mechanical, diaphragm or piston | Mechanical, diaphragm | Mechanical, piston-controlled | Electronic, sensor with display | Mechanical, intrinsically safe design |
| Pressure range | Low pressures up to bar range | Standard compressed air range | High-pressure version | Measuring ranges also with vacuum component | Depending on variant, like standard series |
| Display / Adjustment | Adjustment scale | Adjustment scale | Adjustment scale, rotatable connection | Digital display, two switching outputs | Adjustment scale |
| Output | Changeover contact | Changeover contact | Changeover contact | PNP/NPN switching outputs, NO/NC selectable | Changeover contact, limited connection ratings |
| Media per series specification | Air, water, neutral oils | Air, water, hydraulic oil | Air, water, hydraulic oil | Wetted parts stainless steel/FKM | Same as standard series, approval per datasheet |
| Typical application | Filter and line pressure monitoring | Pneumatics, water, hydraulics | Hydraulic high pressure | Systems with documented switching points | Ex zones per system documentation |
Product Range
Our pressure switch series at a glance
Each series is managed as its own category – from mechanical diaphragm designs through high-pressure and stainless steel to electronic and ATEX variants.
Applications
Typical applications for pressure switches
Whether line pressure, pump control, aggressive media or Ex zone – series selection follows the medium, pressure range and ambient requirements.
Compressed air and pneumatics
Monitoring line pressure, providing a release signal for downstream consumers, and signalling pressure drop in the air service unit. For a pneumatic pressure switch, the 901.9, PDS or PS48 series are commonly selected; for very low pressures, the 901.6 series is an option.
Water, Hydraulic and Oil Circuits
Pump control, dry-run protection, inlet and outlet pressure monitoring. Series listed for air, water and hydraulic oil applications (PDS, HDS) are the usual starting point here; in the high-pressure range, selection regularly leads to the HDS series.
Gases and Mildly Aggressive Media
If the medium attacks NBR diaphragms, material selection is key: series with stainless steel media contact and PTFE or FKM seals (ADS, PS48) are the right direction. Let us know the medium, concentration and temperature – we'll check resistance against the datasheet.
Hazardous Areas (ATEX)
Where an Ex zone is present, the pressure switch must match the required marking and zone and may only be operated within permitted connection ratings. The 901.6-EX and 901.9-EX series, and – for vacuum – the 901.7-EX series, are available for this.
Vacuum, Handling and Gripper Technology
Vacuum chambers, extraction and gripper systems require vacuum monitoring. The 901.7 series vacuum switches are graded by vacuum range; for liquids, mounting position and media compatibility should be clarified in advance.
Filling and Cleaning Processes
For processes with frequent cleaning and changing media, versions with stainless steel media contact and FKM or PTFE diaphragms (PS48, ADS) are the right direction. Special cleaning requirements and alternative diaphragm materials are reviewed on a project basis.
Ordering from STASTO
Request and Order Pressure Switches Online
Availability varies depending on series and variant: common setpoint ranges of the standard series can generally be arranged for short-term delivery, while EX versions, special seals, and special cleaning are procured depending on the variant. We will provide the binding lead time upon request or confirm it in the quote for the specific item number.
Quote for the specific variant
Receive a quote and availability check for the specific version on request – including verification of setpoint range and connection specifications.
Recurring demand
We organize framework call-offs and spare parts stocking for common series by arrangement.
Technical documentation
We provide datasheets and technical documentation for the respective series on request – especially for ATEX ratings.
Special versions
Specially cleaned variants or alternative diaphragm materials are evaluated on a project basis.
How Selection Works
Three steps to the right pressure switch
The more precise the details on medium, pressure and connection, the faster the right variant can be identified.
Describe your application
Tell us the medium, pressure range, desired switching point, process connection and switching capacity – for hazardous areas also the zone, equipment group and temperature class.
Narrow down series and variant
We assign the right series – mechanical, electronic, high-pressure, vacuum or EX – and check switching differential, overpressure safety and materials against the datasheet.
Quote and Procurement
You receive a quote for the specific part number with a confirmed lead time; for recurring needs, we can arrange framework agreements.
FAQ
Frequently Asked Questions About Pressure Switches
Answers on function, designs, ATEX versions, voltages, and vacuum applications.
What does a pressure switch do?
A pressure switch monitors the pressure in a system and actuates an electrical contact once a set value is reached. This allows you to control pumps and compressors, signal limit values, or shut down systems in the event of over- or under-pressure.
What's the difference between mechanical and electronic pressure switches?
Mechanical designs switch a contact directly via a diaphragm or piston, usually as a changeover contact with a setting scale; electronic pressure switches measure via a sensor and display the actual value digitally. Electronic series such as PS15 or PS17 additionally offer two freely configurable switching outputs and more finely adjustable switching logic.
What is an ATEX (explosion-proof) pressure switch?
An ATEX pressure switch is designed for use in hazardous areas and must only be operated within the permitted connection ratings. STASTO offers its own 901.6-EX and 901.9-EX series for this, plus the 901.7-EX for vacuum applications; equipment group, category, and temperature class vary by version and must always be checked against the datasheet of the specific variant.
What is the switching differential (hysteresis) on a pressure switch?
The switching differential is the pressure difference between the switch-on point and the reset (switch-off) point. It prevents the system from cycling due to minor pressure fluctuations – on mechanical series it's fixed depending on the variant, while on electronic versions it's usually freely adjustable.
Can a pressure switch directly switch a 400V three-phase load?
In practice, the changeover contact is mostly used as a potential-free control contact wired to a contactor, PLC, or motor protection relay. Whether direct load switching – for example, on a 400V compressor – is permissible depends on the contact ratings of the specific variant; when in doubt, wire in a contactor.
Which pressure switch is suitable for compressed air?
For compressed air applications, the 901.9, PDS, or PS48 series are frequently chosen, while the 901.6 series is used for very low pressures. Decisive factors are the adjustment range, switch point, overpressure safety, and the desired process connection.
Are there pressure switches for vacuum and for liquids?
Yes – for vacuum applications, STASTO offers vacuum switches of the 901.7 series as a dedicated category, graded by vacuum range, as well as the 901.7-EX series. For liquids, mounting position and media compatibility need to be clarified in advance.
Which pressure switch is suitable for slightly aggressive media?
If NBR is not suitable as the diaphragm material, versions with stainless steel media contact and PTFE or FKM diaphragms are the right choice – such as the ADS and PS48 series. We check the compatibility with your medium on a project basis against the datasheet.
Complementary Products
Related Categories in the Measurement and Monitoring Range
Pressure switches rarely operate in isolation: vacuum switches, flow switches, pressure gauges, and magnetic switches complement the monitoring of your system.
Sizing
Find the Right Pressure Switch – with Technical Guidance
Tell us the medium, pressure range, switching capacity, and process connection – for hazardous areas, also specify the zone and temperature class. We'll narrow down the right series and confirm availability and lead time in our quote.