Closed Center vs Open Center Hydraulics: Understanding the Difference for JCB 217S

[MikePhua]

Understanding the type of hydraulic system in your heavy equipment is crucial for proper maintenance, repairs, and performance. In particular, JCB 217S, like many other skid steers and loaders, could be equipped with either a closed center or an open center hydraulic system. This article delves into the differences between these two systems, how to identify which system your JCB 217S uses, and the implications for operating and maintaining the machine.
Closed Center Hydraulic System
A closed center hydraulic system is designed to maintain constant pressure in the hydraulic lines. In this system, the hydraulic pump is continuously working, supplying oil to the system, but the flow is directed only when there’s a demand for it, which helps to minimize energy loss.
In a closed center system, the pump and valves are tightly integrated, and the flow path is "closed" when there is no demand. This means the system is more energy-efficient, as it does not have to constantly push fluid through the system when not in use. When hydraulic functions are required (such as lifting or tilting), the system opens up the flow path, directing the fluid to the specific hydraulic component.
Advantages of Closed Center Systems:

• Efficiency: Reduced energy consumption as the system only operates when necessary.
  
• Better Control: Provides more consistent and precise control over hydraulic functions.
  
• Higher Capacity: Closed center systems are ideal for applications requiring high-pressure or high-flow demands.
  

Open Center Hydraulic System
On the other hand, an open center hydraulic system has a different mechanism. In this system, the hydraulic fluid continuously circulates through the hydraulic components. The pump constantly supplies fluid to the system, regardless of whether it is being used, which can result in greater energy consumption.
However, when hydraulic functions like lifting or tilting are required, the fluid is diverted through the necessary components. The “open center” part refers to the fluid's continuous flow path through the system, with no constant pressure or restrictions until a demand arises.
Advantages of Open Center Systems:

• Simpler Design: These systems tend to have simpler designs, making them easier to maintain.
  
• Cost-Effective: Generally, open center systems are less expensive to install and repair.
  
• Less Complex: Fewer moving parts can lead to fewer mechanical issues over time.
  

Identifying Closed Center vs Open Center on JCB 217S
Determining which hydraulic system your JCB 217S has is essential for troubleshooting, maintenance, and proper hydraulic function. Here are a few ways to identify the system type:

1. System Design: If you see a constant pressure gauge or feel consistent pressure in the system even when hydraulic functions are idle, it’s likely a closed center system. If the pressure drops or there is little to no pressure when idle, it’s an open center system.
   
2. Hydraulic Valve Behavior: In a closed center system, the hydraulic valves will direct fluid only when demand arises, and the system won’t be constantly under pressure. In an open center system, you’ll notice fluid continuously circulating and more pressure variations.
   
3. Check the Hydraulic Pump: A closed center system typically has a more sophisticated, variable displacement pump, whereas an open center system often uses a simpler, fixed displacement pump.
   
4. Manufacturer Specifications: The easiest and most reliable method is to refer to your JCB 217S operator’s manual or contact the manufacturer directly. The manual will detail which hydraulic system is installed, along with specific maintenance and operation guidelines.
   

Implications of Hydraulic Systems on Operation and Maintenance
Knowing which hydraulic system your equipment uses is important for several reasons:

1. Performance Optimization: Closed center systems are ideal for precise operations that require quick and accurate hydraulic responses. Open center systems are more suited to lighter applications where less control is needed.
   
2. Component Compatibility: Certain attachments and hydraulic components may require specific system types. For example, hydraulic motors, cylinders, or tools may not function efficiently or safely if paired with an incompatible system.
   
3. Maintenance Requirements: Each system requires different maintenance practices. For instance, closed center systems often have more advanced filters and sensors that require periodic checks. Open center systems tend to have simpler filters and components but may require more frequent inspections due to the continuous flow of fluid.
   
4. Troubleshooting: If your system is malfunctioning, knowing whether it is open or closed center will help technicians identify potential issues. For example, issues like oil overheating or inefficiency may be linked to specific components within the hydraulic circuit based on the type of system.
   

Conclusion
Whether your JCB 217S has a closed center or an open center hydraulic system, it is essential to understand the differences and implications for your machine’s operation and maintenance. Each system has its strengths and ideal applications, and identifying the correct type for your skid steer ensures efficient operation, reduced downtime, and proper repair procedures. When in doubt, always refer to the operator’s manual or consult with a professional for the best practices related to your system type.