In hydraulic systems where control, accuracy, and responsiveness are crucial, servo valves play a vital role. These sophisticated electro-hydraulic devices regulate fluid flow and pressure to ensure smooth, precise control in applications ranging from aerospace and energy to industrial automation and manufacturing.
As powerful as they are, servo valves are also highly sensitive, and when problems arise, they can compromise entire systems. That’s why Sealtec Hydraulics, a leading provider of hydraulic valves, seals, and cylinders in South Africa, not only supplies top-tier servo valves from trusted manufacturers but also provides expert guidance and support in troubleshooting common issues.
What Are Servo Valves?
Servo valves are advanced components that control hydraulic fluid flow in proportion to an electrical input. They are used in closed-loop control systems to position actuators with extreme precision, making them ideal for:
- Flight simulators and aerospace equipment
- Plastic injection moulding machines
- Rolling mills and steel production
- Robotic arms and CNC machinery
- Automotive and marine testing systems
Sealtec Hydraulics is an official distributor of leading servo valve brands, including:
- Moog
- Rexroth
- Vickers
- Parker
- Abex
- Denison
- Star Servo Valves
Each brand has its unique strengths, but all are known for reliability, accuracy, and performance in demanding environments.
Common Servo Valve Issues and How to Troubleshoot Them
Erratic or Unstable Operation
Symptoms:
- Inconsistent actuator movements
- Overshooting or oscillation in control position
- System vibrations
Possible causes:
- Contamination or debris in the hydraulic fluid
- Faulty feedback loop (sensor malfunction)
- Incorrect tuning or calibration
Troubleshooting tips:
- Inspect the fluid for contaminants and replace or filter it as needed
- Verify the integrity of sensors and wiring in the control loop
- Check PID controller settings and recalibrate if required
- Ensure the valve spool is moving freely and not sticking
No Response or Limited Movement
Symptoms:
- Valve doesn’t respond to input signals
- Actuator remains stationary
- Reduced range of motion
Possible causes:
- Electrical failure (signal loss or coil damage)
- Blocked or restricted flow paths
- Valve or actuator stuck due to wear or contamination
Troubleshooting tips:
- Use a multimeter to check signal continuity and voltage at the coil
- Test and clean filters, screens, and orifices for clogs
- Disassemble the valve and inspect for worn components or debris
- Confirm that the control signal is within the correct range
Excessive Internal Leakage
Symptoms:
- Reduced system efficiency
- Temperature increase in hydraulic fluid
- Poor actuator performance despite correct signal input
Possible causes:
- Worn or damaged seals and internal components
- Valve body wear
- Cavitation damage
Troubleshooting tips:
- Pressure test the valve to detect internal leakage
- Replace damaged seals or spool components
- Inspect valve surfaces for scoring or erosion
- Consult with Sealtec Hydraulics for seal replacements or valve reconditioning
Overheating of the Servo Valve or Hydraulic System
Symptoms:
- Heat buildup around valve housing
- Unusual noise or fluid foaming
- Increased wear on components
Possible causes:
- Continuous high-load operation
- Inadequate cooling or system design issues
- Excessive internal leakage or bypass
Troubleshooting tips:
- Check system flow rate and pressure settings
- Verify that the heat exchanger or cooling system is working efficiently
- Inspect for leaks or restrictions in fluid flow
- Ensure proper oil viscosity and filtration
Electrical Signal Issues
Symptoms:
- Fluctuating signal response
- System alarms or shutdowns
- Erratic actuator behaviour despite correct fluid flow
Possible causes:
- Loose or corroded connections
- Malfunctioning amplifier or controller
- Signal interference
Troubleshooting tips:
- Inspect wiring harnesses for damage or corrosion
- Shield signal cables to prevent electrical noise
- Replace or test amplifier modules
- Confirm correct grounding of all electrical components
Preventative Maintenance Tips
Servo valves are precision instruments and should be maintained proactively to avoid failure. Here’s how to keep your valves in top condition:
- Use clean, filtered hydraulic fluid – contamination is the number one cause of failure
- Schedule regular system flushes and inspections
- Check seals, filters, and feedback sensors routinely
- Store spare valves and components in clean, dry conditions
- Partner with certified technicians like Sealtec Hydraulics for ongoing support
Why Choose Sealtec Hydraulics for Servo Valves?
As an official distributor of servo valves, Sealtec Hydraulics is your trusted partner for high-performance fluid control systems in South Africa. Here’s what sets us apart:
- Wide Range of Valve Brands: We supply Moog, Rexroth, Vickers, Parker, Abex, Denison, and Star Servo Valves, allowing us to tailor solutions for virtually any industry or application.
- Technical Support and Repair Services: Our experts don’t just sell valves; we support their full lifecycle with troubleshooting, reconditioning, and component replacement services.
- Specialised Applications: We provide servo valve solutions for complex, high-pressure, and mission-critical applications where precision and durability are non-negotiable.
- Quality, Guaranteed: All our servo valves are manufactured with high-grade materials, rigorously tested, and backed by industry best practices.
FAQs: Servo Valves
What does a servo valve do?
A servo valve controls the flow and pressure of hydraulic fluid based on electrical signals. It provides precise, real-time control of actuators in advanced machinery.
How can I determine if my servo valve is malfunctioning?
Watch for erratic actuator movements, system overheating, reduced responsiveness, or fluid leaks. These are signs that the servo valve may be malfunctioning.
Can servo valves be repaired?
Yes. Many servo valves can be reconditioned by replacing their seals, coils, or other components. Sealtec Hydraulics offers diagnostics and repair services for multiple brands.
How often should servo valves be serviced?
Service intervals vary depending on usage and application, but most systems benefit from annual inspections and fluid analysis.
Do you offer technical support for all valve brands?
Yes. We support a wide range of brands, including Moog, Parker, Vickers, Denison, Rexroth, Abex, and Star Servo Valves.
Ensure Smooth Operation with Expert Valve Support
Servo valves are the cornerstone of modern hydraulic control systems. When they fail, the results can be costly and disruptive. That’s why Sealtec Hydraulics offers not only top-tier servo valve products but also the knowledge, service, and support you need to keep your systems running efficiently.
Whether you’re experiencing a performance issue or simply want to extend the life of your system, trust us for all your servo valve troubleshooting, supply, and repair needs.
Contact Sealtec Hydraulics today for expert advice, replacement parts, or full-service servo valve support across South Africa.