1. Pre-Installation Preparation & Safety

1.1 What safety precautions must be observed before installing the valve?

• Energy Isolation: Ensure the hydraulic system’s power supply (pump motor) and the valve’s electrical power are completely disconnected and locked out/tagged out (LOTO) to prevent accidental activation.
• Pressure Relief: Fully relieve all pressure in the hydraulic lines connected to the valve. Open the system’s pressure relief valve and actuate all hydraulic cylinders/motors to drain residual pressure—failure to do so may result in sudden fluid ejection or component movement.
• Personal Protective Equipment (PPE): Wear safety goggles, oil-resistant gloves, and protective footwear to guard against oil splashes and mechanical hazards.
• Environmental Protection: Place oil-absorbent pads around the work area to contain any spilled hydraulic fluid, preventing ground contamination and slips.
• Tool Verification: Use only calibrated, appropriate tools (e.g., torque wrench, flare nut wrench) to avoid damaging valve ports or fasteners.

1.2 What system checks are needed before valve installation to avoid post-installation failures?

1. Pipeline Compatibility: Verify that the diameter and pressure rating of the hydraulic lines match the valve’s port specifications (e.g., P/T/A/B ports). Undersized lines cause pressure drops; oversized lines waste space and increase fluid residence time.
2. Fluid Quality Test: Use a portable oil analyzer to check the hydraulic fluid’s contamination level (per ISO 18/15 standard), water content (≤0.1%), and viscosity. Contaminated fluid will immediately damage the valve’s precision spool and seals.
3. Mounting Surface Inspection: Ensure the valve’s mounting flange (e.g., ISO 4401) is flat, clean, and free of burrs. A warped surface (tolerance >0.1mm per 100mm) will cause valve body distortion and internal leaks.
4. Electrical System Compatibility: Confirm the control system (PLC/DCS) can output a 0-800mA proportional signal and that the power supply can provide stable 24V DC with sufficient current (≥1A) to avoid signal degradation.