Particularly suitable as a pressure limiter for fuel gases (DVGW Worksheet G 260) and liquid fuels, as well as for steam systems according to TRBS and hot water systems according to DIN EN12828, systems according to DIN EN12952-11 and DIN EN12953-9.
 Datasheet
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Particularly suitable as a pressure monitor for fuel gases (DVGW worksheet G 260) and liquid fuels, as well as for steam systems according to TRD 604 and hot water systems according to DIN EN12828, systems according to DIN EN12952-11 and DIN EN12953-9.
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Datasheet
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Especially suitable as a pressure limiter for fuel gases (DVGW work sheet G 260) and liquid fuels (e.g. fuel oil), as well as for steam systems according to TRBS and hot water systems to DIN EN12828, systems in accordance to DIN EN12952-11 and DIN EN12953-9. The DWR-205/-206 is used to limit maximum and minimum pressures and has an internal interlock.
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User Manual
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These series are particularly suitable for maximum pressure monitoring in steam and hot-water systems. The pressure switch is "of special construction", with a self monitoring pressure sensor, built in accordance with Pressure Equipment Directive PED 2014/68/EU. It can be used as a pressure monitor or a pressure limiter for maximum pressure monitoring (systems in accordance with TRBS DIN EN12828) systems in accordance with DIN EN12952-11 and DIN EN12953-9 and is available with or without adjustment. SIL 2 according IEC 61508-2
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Bedienungsanleitung
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In many aspects, safety engineered pressure limiters offer a higher degree of safety compared with normal pressure switches and are therefore especially suitable for chemical process engineering and thermal installations in which safety is an especially critical factor in pressure monitoring. Pressure switches can also be used in Ex- zones (zone 0, 1, 2 and 20, 21, 22) and, in all cases, require an isolating amplifier. The isolating amplifier is also responsible for monitoring lines for short circuit and line break and therefore offers an additional safety advantage – even in non Ex-zones. For Ex-applications, the isolating amplifier must be installed outside the Ex-zone. The lines between the isolating amplifier and the pressure switch are monitored for short circuit and line break. SIL 2 according IEC 61508-2
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Datenblatt
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Bedienungsanleitung
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Pressure limiters of the FD series are constructed in accordance with the special directives for liquid gas engineering. All parts coming into contact with the medium are made of stainless steel 1.4104 and 1.4571. The pressure sensor was designed to be "self-monitoring", i. e. should the measuring bellows rupture, the pressure sensor switches off towards the safe side. The pressure sensor thus complies with "of special construction" in the sense of VdTÜV Memorandum "Pressure 100". Pressure limiters are used in intrinsically safe control circuits (Ex-protection Ex-i). By using an isolating amplifier, the control circuit is also monitored for line break and short circuit.
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User Manual
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DVGW tested to DIN EN1854 Gas pressure monitors are suitable for all gases in accordance with DVGW work sheet G260 and for air.
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User Manual
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Pressure Monitors & Pressure Limiters – Safety and Compliance
Pressure monitors and pressure limiters supervise defined thresholds and safely shut down equipment before damage or hazards occur. Depending on the design, they operate mechanically (diaphragm/piston + microswitch) or electronically (sensor with evaluation) and are available for overpressure, vacuum, and differential pressure. Typical applications include boilers/heating, compressors, hydraulics/pneumatics, process engineering, and building services.
Available with fixed or seal-able (tamper-proof) setpoints, manual or automatic reset, high IP ratings (up to IP67/69K) and optional ATEX/IECEx approvals. ICS Schneider Messtechnik supports selection, sizing, documentation and—if required—integration into safety functions (SIL).
FAQ on Pressure Monitors & Pressure Limiters
Answers on selection, standards, reset strategies, media compatibility, protection classes, connections, commissioning and maintenance.
What is the difference between a pressure monitor and a pressure limiter?
A pressure monitor supervises pressure and switches a contact at the threshold (operational function). A pressure limiter is a safety device: it prevents hazardous overpressure and often requires a manual reset after actuation.
When is a manual reset required?
In safety-relevant applications (e.g., boilers/compressors) where automatic restart is not permitted. The manual reset ensures the system only restarts after inspection.
Are setpoints adjustable or sealable?
Both exist: factory-fixed variants and adjustable versions with seal/tamper protection to prevent manipulation.
Which standards and approvals are relevant?
- Pressure equipment / occupational safety regulations (e.g., PED, local directives)
- ATEX/IECEx in hazardous areas
- SIL/PL when integrated into safety loops (manufacturer/type dependent)
Which contact types are available?
| Contact | Designation | Use |
|---|---|---|
| Normally closed | NC | Safety chain (circuit opens on trip) |
| Normally open | NO | Start/stop signaling |
| Changeover | SPDT | Flexible signaling |
How do I choose range and hysteresis?
As a guideline, select a nominal range of 1.3–2.0 × the working pressure; for pulsation/spikes, size larger. Appropriate hysteresis prevents chatter and extends lifetime.
Which media/material combinations are common?
| Material | Typical media | Note |
|---|---|---|
| Brass | Air, water, oils | Cost-effective; not for aggressive media |
| Stainless steel 316L | Corrosive media | High resistance |
| Hastelloy® / PTFE | Highly chemical media | Special design |
What process connections are typical?
| Connection | Standard | Remark |
|---|---|---|
| G 1/4, G 1/2 | ISO 228 | Industry standard |
| ¼″ NPT, ½″ NPT | ASME | US / oil & gas |
| Tri-Clamp (with diaphragm seal) | DIN/ASME | Hygienic applications |
What IP ratings / Ex approvals are possible?
Typically IP54–IP67/69K. In hazardous areas, ATEX/IECEx variants (e.g., Ex ia/ib) are available.
How do I protect against pressure spikes and temperature?
Use a snubber/restrictor for pressure surges, and a siphon/cooling element for steam/hot media; verify seal and housing material for compatibility.
How is the electrical integration into safety loops done?
Often via NC contact in the safety chain; wire according to the manufacturer’s schematic. For SIL/PL, consider diagnostics and proof-test intervals.
How do I set the setpoint correctly?
Depending on type via adjusting screw or factory-fixed. After setting, verify with a reference pressure and document as-found/as-left; apply seal if applicable.
What test and maintenance intervals are recommended?
Rule of thumb annually; for safety-critical applications semi-annually/quarterly. Perform functional and leak tests and visual inspection (leaks, cabling, corrosion).
Typical use cases?
- Boiler/heating systems: maximum pressure supervision
- Compressor/pump systems: shutdown on over-/underpressure
- Process engineering: protection of lines, filters, reactors
- HVAC/building services: room/duct pressure monitoring
Do you support selection and documentation?
Yes. We advise on range/hysteresis, materials/seals, reset strategy, provide documents/certificates, and support commissioning & acceptance.