Operation Precautions & Daily Maintenance for EM-SD25  Control Valve

Operation Precautions & Daily Maintenance for EM-SD25  Control Valve

Operation Precautions

1. Working Condition Matching

The EM-SD25 control valve shall work within the rated parameters: max parallel‑circuit working pressure 315 bar, nominal flow 240 L/min, suitable for mineral hydraulic oil with viscosity of 12‑400 mm²/s. Do not run under over‑pressure, over‑flow or long‑term overload conditions, otherwise internal spool and sealing parts will suffer accelerated wear.

2. Installation Requirements

Mount the valve body on a flat rigid mounting surface to avoid valve‑section deformation and spool sticking caused by uneven stress. Keep plastic port plugs in place before painting to prevent paint from entering oil ports. Do not modify valve structure, relief‑valve pressure setting or internal components without manufacturer authorization.

3. Operating Rules

Operate control levers / electro‑hydraulic switches smoothly and steadily. Avoid violent slamming or rapid reversing, which may cause hydraulic impact, pressure spikes and damage load check valves and relief valves.

For manual‑control versions, do not use extra leverage tools to push the lever.

Before startup, confirm all pipe connections are correct and tight. After long‑term shutdown, perform several no‑load stroke cycles to exhaust trapped air inside the valve and pipeline.

4. Environmental & Anti‑pollution Requirements

Keep the hydraulic oil clean; oil contamination is the main cause of spool jamming and valve failure. Do NOT use high‑pressure water jet directly washing the valve assembly, to prevent water penetrating into lever box, control mechanism and interior of the valve, resulting in rust and stuck spools. Protect the valve from heavy dust, mud and corrosive media.

5. Safety before Maintenance

Cut off system power completely, and fully release residual hydraulic pressure before any disassembly, inspection or maintenance work. Never disassemble the valve under pressurized condition, to prevent hydraulic‑oil injection injury.

Daily & Routine Maintenance

Daily Inspection (Before Each Shift)

- Check all valve ports, pipe joints and flange surfaces for hydraulic‑oil leakage. Replace failed O‑rings or tighten loose fittings immediately if seepage occurs.

- Observe operation feedback: confirm spool shifting is smooth, no sticking, lagging, abnormal vibration or noise during lever operation.

- Check valve mounting bolts for looseness; inspect control levers, connecting cables and linkage parts for deformation or loose connection.

- Check hydraulic‑oil level and visual oil condition; stop operation if oil turns cloudy, emulsified or contains visible impurities.

Weekly Maintenance

- Tighten all mounting bolts and pipe connectors following manufacturer‑specified torque values.

- Clean dust, sludge and debris from valve outer surface, lever assembly and control housing.

- Check relief‑valve working pressure under actual working conditions; ensure pressure setting complies with system requirements.

- Inspect filter clogging indicator; replace hydraulic filter element promptly when differential pressure exceeds threshold.

Monthly Maintenance

- Take hydraulic‑oil samples for contamination inspection. Keep oil cleanliness meeting ISO 14/11 standard; replace oil if seriously contaminated.

- Check load‑holding performance of built‑in load check valves: verify no obvious drifting of hydraulic cylinder under static load.

- Inspect the condition of seals, return springs and control components. If slight external leakage appears, check seal aging status.

Periodic Overhaul (Every 2000‑3000 working hours)

- Disassemble and clean valve body, spools, relief valve cartridges and check‑valve components with dedicated hydraulic cleaning solvent. Blow‑dry completely with dry compressed air.

- Replace all O‑rings, sealing gaskets and wearing parts. Do not reuse aged or deformed seals.

- Inspect spool surface for scratches, burrs and wear; polish minor scratches, replace spool assembly if excessive wear exists.

- Re‑calibrate main relief‑valve pressure, test no‑load and full‑load working cycles, confirm all functions work normally.

- Complete maintenance records, note down inspection time, oil‑change status and replaced spare‑part information.

Common Warning Remarks

If spool jamming, serious leakage, pressure loss or cylinder drifting occurs during operation, stop equipment immediately and carry out inspection. Do not continue running with faults. Only use genuine or manufacturer‑approved replacement spare parts.