SD4 SD5-1 Walvoil Remote Control Hydraulic Valve 45L 250bar

Product Overview

The SD4, SD5-1, SD8-1, SD11-1, SD14, SD180-1 and SD25-1 are Walvoil (or equivalent) SD Series monoblock and sectional directional control valves designed for open-center and closed-center hydraulic systems. They support manual, pneumatic, hydraulic, electro-hydraulic and flexible-cable remote control. The SD4 is a compact single-section valve rated at 45 L/min and 250 bar; the SD5 series offers 1–6 sections with main relief and load-check valves up to 315 bar. Interchangeable spools (16–25 mm diameter) and modular construction provide full drop-in interchangeability with original SD remote-control valve assemblies. Every unit undergoes 100% simulated operating-condition testing for reliable directional control and remote operation on mobile machinery.

Technical Specifications 

• Models: SD4, SD5-1, SD8-1, SD11-1, SD14, SD180-1, SD25-1
• Type: Monoblock / sectional directional control valve (remote cable control compatible)
• Nominal flow: SD4/SD5 approx. 45 L/min (12 US gpm); SD8 approx. 80–90 L/min; SD14 approx. 120 L/min; SD25 approx. 240 L/min (63 US gpm)
• Maximum operating pressure: SD4 250 bar (3600 psi); SD5/SD8/SD11/SD25 up to 315 bar (4600 psi, parallel circuit)
• Spool diameter: 16 mm (SD4/SD5); larger diameters for higher-flow models
• Control options: Manual lever, pneumatic, hydraulic, electro-hydraulic, solenoid, flexible-cable remote control kits
• Circuit options: Parallel, series, tandem; optional power-beyond port
• Main relief and load-check valves: Standard on most models
• Maximum tank-port back pressure: approx. 25 bar
• Internal leakage: typical approx. 3 cm³/min (A/B to T @ 100 bar)
• Operating temperature: Fluid approx. –20…+80 °C; Ambient –40…+60 °C (depending on control type)
• Recommended filtration: ISO 4406 19/16 or cleaner

Key Technical Advantages

1. Flexible-cable remote control: Dedicated remote kits (TQ/CD etc.) enable precise long-distance operation with simple installation and no additional hydraulic lines.
2. Interchangeable spools and modular design: Standardized spool diameters allow easy function changes (double-acting, single-acting, closed/open center) and flexible 1–12 section configurations.
3. Full interchangeability: Exact compatibility with Walvoil SD series interfaces and control kits for drop-in replacement of original remote-control valve assemblies.
4. Compact heavy-duty construction: Robust housing with main relief and load-check valves, low pressure drop, suited to severe vibration and duty cycles on mobile equipment.
5. 100% factory testing: Validated under simulated conditions to ensure reliable remote response, low leakage and long service life.

Application Areas

• Wood splitters, small dumpers, small tractors and workshop presses (SD4)
• Harvesting machines, brush cutters, conveyors, balers, small front loaders and truck-mounted cranes (SD5)
• Forklifts, stackers, all-terrain cranes, garbage compactors, large agricultural loaders and earth-moving machines (SD25 and higher-flow models)
• Mobile hydraulic systems requiring cable or hydraulic pilot remote control
• OEM service and aftermarket replacement of SD Series remote-control valve assemblies

Expert Maintenance Tips

1. When installing remote cable kits, avoid sharp bends or binding; secure the cable properly to prevent increased operating force or spool sticking.
2. Regularly check main relief-valve setting and load-check valve function to protect against over-pressure or load drop.
3. Maintain fluid cleanliness to the recommended class and correct viscosity to avoid spool sticking; lubricate moving parts of remote-control linkages periodically.
4. When replacing spools, clean the body bores thoroughly, fit correct seals and torque fasteners to specification; ensure waterproof caps on the cable-control side remain intact.
5. After long storage, cycle the valve manually several times to confirm remote response before applying full system load.