Description
1/2" High Pressure Normally Open Solenoid Valve – NOPU225H-04
25 Bar Brass Normally Open Solenoid Valve – SHAKO PU225HN-04
The SHAKO NOPU225H-04 (PU225HN-04) is a high-pressure 1/2" pressure-assisted 2/2 way normally open brass solenoid valve designed for demanding fluid and gas control applications at pressures up to 25 Bar.
The valve is open when de-energised and closes when energised, making it suitable for systems requiring flow to be maintained following loss of electrical power.
Featuring a forged brass body, SUS304 stainless steel internals and a nylon-reinforced diaphragm, the NOPU225H-04 provides reliable high-pressure operation with quick response and excellent durability. Suitable for compressed air, water, light oils and compatible gases, with alternative seal materials available for improved chemical compatibility.
Technical Specification
Function: 2/2 way normally open
Valve State: De-energised OPEN / Energised CLOSED
Operation: Pressure-assisted pilot operated diaphragm
Minimum Pressure Differential: 0.5 Bar
Operating Pressure Range: 0.5 to 25 Bar
Operating Pressure with ATEX Coil: 0.5 to 20 Bar maximum
Proof / Test Pressure: 30 Bar
Port Size: 1/2" BSPP female
Optional Threads: NPT or Rc
Orifice Size: 8.0mm
Kv Flow Factor: 28.6 L/min based on water with 1 Bar pressure drop
Body Material: Forged brass
Internal Components: SUS304 stainless steel
Standard Seal: NBR
Diaphragm: Nylon reinforced
Optional Seals: EPDM, FKM (Viton®) or HNBR
Suitable Media: Compressed air, water, light oils and compatible fluids and gases up to 50 CST
Media Temperature: -10°C to +90°C
Ambient Temperature: -10°C to +60°C
Seal Material Options
NBR: Standard general-purpose seal for air, water, neutral gases and mineral oils
EPDM: Optional for water and compatible fluids
FKM (Viton®): Optional for oils, fuels and compatible chemicals
HNBR: Optional for applications requiring improved chemical compatibility
Maximum valve media temperature remains +90°C regardless of seal material selected due to the nylon-reinforced diaphragm construction.
Coil & Electrical Specification
Coil System: Nass Magnet System 13/36
Power Consumption: 18.5 Watts
Insulation Class: Class H
Duty Rating: 100% continuous duty
Protection Rating: IP65 with connector fitted
Electrical Connector: DIN 43650 Form A
Connector: Included
Voltage Options
DC:
12VDC, 24VDC, 48VDC, 110VDC or 220VDC
AC 50/60Hz:
12VAC, 24VAC, 48VAC, 110VAC, 230VAC or 380VAC
ATEX / IECEx Coil Option
Optional Nass Magnet explosion-protected solenoid operator available.
✓ Ex mb IIC T4 Gb
✓ Ex mb tb IIIC T130°C Db
✓ Suitable for Zone 1 gas and Zone 21 dust hazardous areas
✓ ATEX Category 2G / 2D
✓ Protection rating: IP65
✓ Maximum operating pressure: 20 Bar
✓ Maximum media temperature: +80°C
✓ ATEX Certificate: PTB 03 ATEX 2086 X
✓ IECEx Certificate: IECEx PTB 05.0005X
✓ ATEX Directive: 2014/34/EU
Important: The standard NOPU225H-04 valve is rated to 25 Bar, but maximum operating pressure is reduced to 20 Bar when fitted with the ATEX solenoid operator. Maximum media temperature is also reduced to +80°C.
Why Choose a Normally Open High Pressure Valve?
Normally open high-pressure solenoid valves are useful where flow is required in the de-energised state or must automatically resume following electrical power loss.
The NOPU225H-04 combines this fail-open function with operation up to 25 Bar, a 30 Bar proof/test pressure and compact 1/2" BSP construction, making it particularly suitable for high-pressure industrial fluid and gas control.
Benefits
✓ Fail-open operation on power loss
✓ High-pressure capability up to 25 Bar
✓ 30 Bar proof / test pressure
✓ Quick-response diaphragm design
✓ Reinforced diaphragm for durability
✓ Compact high-flow construction
✓ Suitable for fluids and gases
✓ Serviceable diaphragm construction
✓ Free UK delivery available
Typical Applications
High-pressure water systems
Compressed air installations
Fail-open process control systems
Industrial process equipment
Pneumatic equipment
Water treatment equipment
Medical and healthcare equipment
Boiler and utility systems
Light oil systems
OEM machinery
General industrial automation
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