Description
1/2" WRAS Normally Open Water Solenoid Valve – ASCO Sirai L282D01
The ASCO Sirai L282D01-1/2 is a 1/2" BSP WRAS approved normally open brass solenoid valve designed for potable water, commercial water services and industrial water-control applications.
Unlike a conventional normally closed water valve, the L282 is open when de-energised and closes when electrical power is applied. This fail-open operating principle makes it particularly useful where water flow is required to continue automatically following a loss of electrical power.
The pressure-assisted diaphragm design, 13.5mm orifice and Kv 3.8 m³/h provide substantial flow capacity from a compact 1/2" valve, with only 0.35 Bar minimum differential pressure required.
Valve Function & Operation
Function: 2/2 Way Normally Open
Fail Position: Open
Energised Position: Closed
Operation: Pressure Assisted Diaphragm
Design: Full Orifice Pilot Operated
Minimum Differential Pressure: 0.35 Bar
Maximum Allowable Pressure (PS): 20 Bar
The manufacturer describes the L282 as a normally open, pilot-operated diaphragm valve with a full orifice design.
Pressure, Orifice & Flow
Port: 1/2" BSPP Female
Thread Standard: ISO 228
Orifice: 13.5mm
Kv Flow Factor: 3.8 m³/h
Minimum Differential Pressure: 0.35 Bar
Operating Pressure: 0.35–12 Bar
WRAS Approved EPDM Option
The L282 is available with WRAS certified EPDM sealing for potable-water applications.
✓ Latest WRAS Approval No. 250702716
✓ Approval Valid Until 31 July 2030
Body: Brass
Internal Components: Brass & Stainless Steel
Core Tube: Stainless Steel
Seat: Brass
Seal Option: WRAS Approved EPDM
The brass and stainless steel construction provides a durable industrial valve platform while the WRAS EPDM version is intended for potable-water installations.
Potable Water Applications
The WRAS EPDM version is particularly suited to:
✓ Potable Water Systems
✓ Commercial Water Services
✓ Water Treatment Equipment
✓ Process Water
✓ Building Services
✓ OEM Water Equipment
✓ Fail-Open Water Control
For liquids other than water, compatibility with all wetted materials should be confirmed before use. The manufacturer specifies the L282 for compatible liquid and gaseous fluids.
Temperature
NBR: -10°C to +90°C
FPM: 0°C to +130°C
Controlled Switching
Opening Time: Approximately 300–1500ms
Closing Time: Approximately 1000–2000ms
The relatively controlled opening and closing characteristics are beneficial in water systems because they reduce the abrupt hydraulic changes associated with very fast-acting valves.
Solenoid Coil
DC Coil: 5.5 Watts
Duty Cycle: ED 100% Continuous
Insulation: Class F 155°C
Electrical Connection: 3-Pole Connector
Connector Standard: EN 175301-803
DC Protection: IP67 with Connector
AC Coil
The standard AC operator differs electrically from the DC version:
AC Inrush: 11.7VA
AC Holding: 10VA
AC Power: 7.6W
AC Protection: IP65 with Connector
This distinction is worth retaining on the ecommerce page rather than describing every voltage version simply as IP65.
Voltage Options
DC:
✓ 12V DC
✓ 24V DC
AC:
✓ 24V AC
✓ 120V AC
✓ 230V AC
Other voltages and frequencies are available on request.
Normally Open Fail-Safe Operation
The major difference between the L282 and L182 families is the de-energised valve position.
With no electrical power applied, the L282 remains open and permits water flow. Applying power closes the valve.
This makes the L282 particularly useful where the system design requires the water path to automatically reopen following electrical power failure.
It should not, however, automatically be described as a safety valve unless the complete system design and applicable standard specifically require normally open operation.
Installation Dimensions
Overall Body Length: 66mm
Dimension b: 69mm
Dimension c: 83mm
Maximum Body Width: 40mm
Weight: Approximately 0.38kg
Typical Applications
✓ Potable Water Systems
✓ Commercial Water Installations
✓ Water Treatment Equipment
✓ Fail-Open Water Circuits
✓ Process Water Systems
✓ Building Services
✓ OEM Machinery
✓ Cooling Water Circuits
✓ General Water Control
Why Choose the L282 Normally Open Valve?
The L282 is a useful alternative to the more common normally closed water solenoid valve where the required power-failure position is open.
For the 1/2" model, the combination of 13.5mm orifice, Kv 3.8 m³/h and only 0.35 Bar minimum differential pressure provides good flow performance without requiring a physically large valve.
The normally open configuration also means electrical power is only required when the water supply needs to be shut off, making it particularly appropriate for systems that normally remain open for long periods.
L282 Normally Open Range
3/8" BSP – 13.5mm – Kv 2.5 m³/h
1/2" BSP – 13.5mm – Kv 3.8 m³/h
3/4" BSP – 18mm – Kv 5 m³/h
1" BSP – 24mm – Kv 12 m³/h
Larger 1¼", 1½" and 2" normally open L282D-BIG valves are also available.
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