Description
1/2" Normally Open Stainless Steel Solenoid Valve – Pro-Uni-D CNS SUW15NO
The Pro-Uni-D CNS SUW15NO is a 1/2" 2/2 way normally open stainless steel solenoid valve designed for reliable control of air, water, light oils, vacuum and compatible industrial fluids and gases. Its normally open design provides fail-open operation, automatically returning to the open position when electrical power is removed.
Featuring a zero-rated assisted-lift design, the SUW15NO operates from 0 Bar without requiring a minimum pressure differential. This combines the higher flow capability of an assisted diaphragm valve with the ability to operate at zero pressure and under vacuum conditions.
Manufactured from 316 stainless steel (CF8M) with stainless steel internal components and FKM seals as standard, the valve features a large 15mm orifice providing 64.4 L/min water flow at 1 Bar pressure difference. The manufacturer specifies maximum working pressure of 10 Bar, with differential pressure dependent upon media and electrical configuration.
Valve Function & Operation
Function: 2/2 way normally open
Operation: Assisted close / zero-rated assisted lift
Fail-safe position: Open
Electrical operation: Power to close
The SUW15NO remains open when electrically de-energised. When power is applied to the solenoid, the valve closes against the process flow.
Power OFF → Valve OPEN
Power ON → Valve CLOSED
Power failure → Valve returns OPEN
The assisted-lift mechanism mechanically connects the solenoid operation to the main diaphragm assembly. This enables operation from zero differential pressure, unlike a conventional pressure-assisted diaphragm valve that requires inlet pressure to operate.
Ports & Connections
Standard port: 1/2" BSP
Optional threads: NPT and BSPT
Orifice: 15mm
Water flow: 64.4 L/min at 1 Bar pressure difference
The 64.4 L/min figure is based on water with a 1 Bar pressure drop and is therefore stated as water flow rather than conventional Kv in m³/h.
Pressure & Performance
Overall working pressure: 0 to 10 Bar maximum
The manufacturer gives the following differential pressure ratings for the 1/2" SUW15NO:
Water / light oil: 0 to 5 Bar
Air / gas: 0 to 7 Bar
Maximum working pressure: 10 Bar
This distinction is useful because the 10 Bar figure is the maximum working pressure, rather than a blanket 10 Bar differential pressure rating for every media configuration.
Orifice: 15mm
Water flow: 64.4 L/min
Opening / closing time: 150ms maximum
Maximum viscosity: 20 cSt
Vacuum & Zero Pressure Operation
The SUW15NO is suitable for applications requiring operation from zero pressure differential and is also specified for vacuum service.
Manufacturer-listed media include:
Air
Water
Light oil
Vacuum to 10⁻³
The combination of normally open operation, vacuum capability and a large 15mm orifice makes the SUW15NO particularly useful where a conventional pilot-operated normally open valve would be unsuitable.
Construction & Materials
Body: 316 stainless steel CF8M
Tube: Stainless steel
Internal components: Stainless steel
Standard seals: FKM
Optional seals: NBR or Silicone
Coil encapsulation: Moulded resin
The manufacturer's construction specification confirms the 316 stainless steel CF8M body, stainless steel tube and internals, and FKM sealing, with alternative NBR or Silicone seals available.
Seal & Media Compatibility
FKM is supplied as the standard sealing material for this SUW15NO configuration.
Depending upon the selected seal and application, suitable media include:
✓ Compressed Air
✓ Water
✓ Light Oils
✓ Vacuum
✓ Compatible Inert Gases
✓ Compatible Process Fluids
Other slightly aggressive fluids and gases may be suitable where chemically compatible with the 316 stainless steel construction and selected seal material.
Maximum media viscosity: 20 cSt
For aggressive chemicals or specialist gases, compatibility should be confirmed before ordering.
Temperature Range
Maximum media temperature: +120°C
Ambient temperature: -5°C to +50°C
The complete operating temperature range is dependent upon the selected seal, media and electrical configuration.
Installation & Mounting
Recommended mounting position:
Vertical with the solenoid coil uppermost
Correct installation helps ensure reliable operation of the assisted-lift diaphragm mechanism.
The manufacturer specifically states coil-upright mounting for this series.
Pipework should be clean before installation to prevent contamination from entering the valve or restricting movement of the diaphragm and armature.
Coil & Electrical
Coil type: M
Insulation: Class H 180°C
Duty cycle: 90%
Protection: IP65 with connector
Electrical connection: DIN 43650
Coil construction: Moulded resin
Voltage Options
Standard electrical configurations include:
✓ 24VDC
✓ 110VAC
✓ 230VAC
Normally Open Fail-Safe Operation
One of the principal advantages of the SUW15NO is its normally open fail-safe function.
When electrical power is unavailable, the valve remains open. Energising the solenoid closes the valve.
This configuration can be useful for cooling, circulation, venting and other industrial processes where the required system response following electrical power failure is an open flow path.
The suitability of a normally open fail position should always be determined according to the safety requirements of the complete system.
Typical Applications
✓ Compressed Air Systems
✓ Industrial Water Systems
✓ Vacuum Systems
✓ Light Oil Control
✓ Inert Gas Systems
✓ Process Water Equipment
✓ Cooling Water Systems
✓ Industrial Process Control
✓ OEM Machinery
✓ Test Equipment
✓ Laboratory Equipment
✓ Fail-Open Control Systems
High-Flow Zero-Rated Design
A major advantage of the SUW15NO is its combination of zero-pressure operation and a large 15mm flow orifice.
Conventional servo-operated diaphragm valves normally require a minimum pressure differential to operate. The assisted-lift construction of the SUW15NO allows mechanical assistance from the solenoid operator, enabling operation from 0 Bar while retaining the higher flow capacity associated with a diaphragm valve.
For applications requiring normally open operation at low or zero differential pressure, this provides an important alternative to both conventional pilot-operated valves and smaller-orifice direct-acting designs.
Repair & Maintenance
Replacement components are available for the SUW-NO Series, including:
Diaphragm seal kits
Replacement solenoid coils
Armature assemblies
Ordering Information
Select the required:
Port – 1/2" BSP, NPT or BSPT
Seal – FKM standard or alternative
Voltage – AC or DC
Media and operating pressure
For unusual fluids, vacuum applications or aggressive media, please confirm the application before ordering.
Please contact us for quantity discounts or assistance selecting the correct configuration.
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