Description
3/8" High Pressure Normally Open Solenoid Valve – NOPU225H-03
25 Bar Brass Normally Open Solenoid Valve – SHAKO PU225HN-03
The SHAKO NOPU225H-03 (PU225HN-03) is a high-pressure 3/8" 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-03 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.
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
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: 3/8" 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.
The temperature limitation applies to the complete PU225H valve and nylon-reinforced diaphragm construction rather than simply the temperature capability of the elastomer selected. SHAKO's current PU225H information also specifies a complete-valve media range of -10°C to +90°C.
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 Hazardous Area Option
Optional explosion-protected solenoid operator available for hazardous-area applications.
✓ Ex mb IIC T4 Gb
✓ Ex mb tb IIIC T130°C Db
✓ Temperature class T4 / T130°C
✓ Maximum operating pressure: 20 Bar
✓ Maximum media temperature: +80°C
✓ Protection rating: IP65
Important ATEX limitation: Although the standard NOPU225H-03 valve is rated for operation up to 25 Bar, maximum operating pressure is reduced to 20 Bar when fitted with the ATEX coil. Maximum media temperature is also reduced to +80°C.
Why Choose a Normally Open High Pressure Valve?
The SHAKO NOPU225H-03 combines normally open operation with substantially higher working pressures than conventional general-purpose normally open solenoid valves.
The valve remains open without electrical power and closes when energised, making it suitable where maintaining flow is the required power-loss condition.
The standard version operates from 0.5 to 25 Bar, with a 30 Bar proof/test pressure, 8mm orifice and Kv 28.6 L/min flow capacity. When the optional ATEX operator is selected, maximum operating pressure is 20 Bar.
Repair Kits & Maintenance
Replacement diaphragm repair kits are available with NBR, EPDM, FKM or HNBR sealing options, allowing the valve to be serviced rather than replaced.
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