RPCC-LAN Sun Hydraulics Relief Cartridge Valve

Product Overview

The Sun Hydraulics RPCC-LAN, RPEC-LAN, CBEY-LAN, CBGY-LAN, MWEM-XIN and MWGM-XIN are screw-in cartridge valves designed for industrial and mobile hydraulic systems. However, they represent three different hydraulic functions and should not be marketed as one generic pressure-relief product.

RPCC-LAN and RPEC-LAN are pilot-operated, balanced-piston relief cartridges. CBEY-LAN and CBGY-LAN are standard counterbalance valves using a 2:1 pilot ratio. MWEM-XIN and MWGM-XIN are vented, balanced, non-relieving load-control valves. Sun’s official documentation explicitly states that the MWEM/MWGM family has no relief function and controls flow through pilot pressure.

The product family covers several flow capacities, from 45 L/min for RPCC-LAN to 240 L/min for CBGY-LAN and MWGM-XIN, allowing engineers to match valve capacity to hydraulic circuit requirements.

For replacement applications, the correct engineering approach is to verify the complete model number, cartridge cavity, pressure range, pilot ratio, control method, seal material, installation torque and hydraulic function before installation.

Our replacement units can also be subjected to 100% simulated working-condition testing to verify pressure response, pilot control, leakage behavior and repeated-cycle stability.

Technical Specifications

RPCC-LAN

• Model: RPCC-LAN
• Brand: Sun Hydraulics
• Valve Type: Pilot-operated, balanced-piston relief cartridge
• Cavity: T-162A
• Nominal Capacity: 45 L/min (12 GPM)
• Maximum Operating Pressure: 350 bar (5000 psi)
• Typical Response Time: 10 ms
• Factory Test Flow: 15 L/min (4 GPM)
• Minimum Setting: 5 bar (75 psi)
• Adjustment: 5 turns
• Typical Leakage: approximately 30 cc/min at 70 bar
• Installation Torque: 35–40 Nm
• Weight: approximately 0.14 kg
• Seal Options: Buna-N / Viton depending on configuration
• Function: Normally closed pressure relief/regulation.

RPEC-LAN

• Model: RPEC-LAN
• Brand: Sun Hydraulics
• Valve Type: Pilot-operated, balanced-piston relief cartridge
• Cavity: T-10A
• Nominal Capacity: 95 L/min (25 GPM)
• Maximum Operating Pressure: 350 bar (5000 psi)
• Typical Response Time: 10 ms
• Factory Test Flow: 15 L/min (4 GPM)
• Minimum Setting: 5 bar (75 psi)
• Main-Stage Protection: 150 μm stainless-steel screen
• Typical Leakage: approximately 30 cc/min at 70 bar
• Installation Torque: approximately 40–50 Nm
• Weight: approximately 0.14 kg
• Pressure Adjustment: 5 turns
• Back Pressure: Tank-port back pressure adds 1:1 to the valve setting
• Application Limitation: Not recommended for load-holding applications due to spool leakage.

CBEY-LAN

• Model: CBEY-LAN
• Brand: Sun Hydraulics
• Valve Type: Counterbalance valve
• Cavity: T-2A
• Nominal Capacity: 120 L/min (30 GPM)
• Pilot Ratio: 2:1
• Adjustment Range: 70–280 bar for the A pressure range
• Alternative Range: 28–105 bar for the B range
• Adjustment: Standard screw for L-control configuration
• Seal: Buna-N / Viton
• Weight: approximately 0.29 kg
• Primary Function: Load holding and controlled actuator motion.

CBGY-LAN

• Model: CBGY-LAN
• Brand: Sun Hydraulics
• Valve Type: Counterbalance valve
• Cavity: T-17A
• Nominal Capacity: 240 L/min (60 GPM)
• Pilot Ratio: 2:1
• Adjustment Range: 70–280 bar for the A range
• Alternative Ranges: available according to the complete control/check configuration
• Adjustment: Standard screw for L-control configuration
• Seal: Buna-N / Viton
• Weight: approximately 0.62 kg
• Primary Function: High-flow load holding and controlled lowering.

MWEM-XIN

• Model: MWEM-XIN
• Brand: Sun Hydraulics
• Valve Type: Vented, balanced, non-relieving load-control valve
• Cavity: T-22A
• Nominal Capacity: 120 L/min
• Maximum Operating Pressure: 350 bar
• Pilot-Control Pressure Options: 5, 10.5, 14, 20, 33 and 36.7 bar depending on configuration
• Control Method: Pilot-pressure controlled
• Relief Function: None
• Operating Principle: Load-pressure balanced and self-compensating
• Recommended Operation: Meter-out
• Installation Torque: 60–70 Nm
• Seal: Buna-N / Viton.

MWGM-XIN

• Model: MWGM-XIN
• Brand: Sun Hydraulics
• Valve Type: Vented, balanced, non-relieving load-control valve
• Cavity: T-23A
• Nominal Capacity: 240 L/min
• Maximum Operating Pressure: 350 bar
• Control Method: Pilot-pressure controlled
• Relief Function: None
• Operating Principle: Self-compensating load-pressure balancing
• Recommended Operation: Meter-out
• Installation Torque: 200–215 Nm
• Seal: Buna-N / Viton depending on ordering configuration.

Key Technical Advantages

Balanced-Piston Pressure Regulation

RPCC-LAN and RPEC-LAN use pilot-operated balanced-piston technology to provide relatively low pressure rise with increasing flow, smooth operation and a typical response time of approximately 10 ms.

2:1 Pilot-Ratio Counterbalance Control

CBEY-LAN and CBGY-LAN use a 2:1 pilot ratio, providing controlled load release and actuator movement for hydraulic circuits requiring dependable load management.

Multiple Flow Classes

The platform covers several capacity levels:

• RPCC-LAN → 45 L/min
• RPEC-LAN → 95 L/min
• CBEY-LAN → 120 L/min
• CBGY-LAN → 240 L/min
• MWEM-XIN → 120 L/min
• MWGM-XIN → 240 L/min

This allows engineers to select a cartridge according to circuit flow rather than forcing one valve size across different hydraulic applications.

Floating Cartridge Construction

Sun’s floating construction is designed to reduce the possibility of internal component binding caused by excessive installation torque or cartridge-cavity machining variation.

Protected Pilot Orifice

The RPEC-LAN incorporates a 150 μm stainless-steel screen protecting the main-stage orifice, providing additional protection for the pilot-controlled hydraulic path.

Self-Compensating Load Control

MWEM-XIN and MWGM-XIN balance against load pressure and use pilot pressure to control flow, creating a self-compensating load-control architecture.

Modular Cartridge Integration

The cartridge architecture simplifies integration into manifolds and supports replacement-oriented hydraulic design. Sun documentation also identifies interchangeability among certain same-frame-size two-port relief cartridges when cavity and flow-path requirements match.

Application Areas

RPCC-LAN / RPEC-LAN

• Hydraulic power units
• Pressure-control manifolds
• Industrial hydraulic systems
• Mobile hydraulic systems
• Hydraulic motor circuits
• Cross-port relief circuits
• Pressure-protection circuits

CBEY-LAN / CBGY-LAN

• Hydraulic cylinders
• Lifting equipment
• Material-handling machinery
• Construction equipment
• Load-holding circuits
• Controlled lowering applications
• Winch systems

MWEM-XIN / MWGM-XIN

• Heavy-duty hydraulic actuators
• Mobile machinery
• High-flow load-control circuits
• Hydraulic cylinders
• Meter-out circuits
• Pilot-controlled motion systems

MWEM-XIN and MWGM-XIN should be selected as load-control valves, not as conventional system relief valves, because Sun explicitly specifies that they have no relief function.

Expert Maintenance Tips

Confirm the Cartridge Cavity

The cavity is a primary replacement criterion:

• RPCC-LAN → T-162A
• RPEC-LAN → T-10A
• CBEY-LAN → T-2A
• CBGY-LAN → T-17A
• MWEM-XIN → T-22A
• MWGM-XIN → T-23A

A cartridge should never be selected from external dimensions alone.

Separate Relief Functions from Load-Control Functions

RPCC/RPEC are pressure-relief cartridges. CBEY/CBGY are counterbalance cartridges. MWEM/MWGM are non-relieving load-control cartridges. They have different hydraulic functions and should not be substituted without circuit analysis.

Account for Tank-Port Back Pressure

For RPCC/RPEC, Sun specifies that back pressure at the tank port adds directly to the valve setting at a 1:1 ratio. This is particularly important in high-flow return lines.

Use the Correct Installation Torque

The documented torque values vary significantly by cartridge size:

• RPCC-LAN → 35–40 Nm
• RPEC-LAN → approximately 40–50 Nm
• MWEM-XIN → 60–70 Nm
• MWGM-XIN → 200–215 Nm

Incorrect torque can affect sealing and cartridge operation, even with Sun’s floating-style construction.

Control Hydraulic Contamination

Keep pilot passages, cavities and sealing surfaces clean during installation and service. The RPEC-LAN’s protected pilot orifice improves contamination tolerance, but filtration and proper hydraulic cleanliness remain essential for reliable operation.

Verify Pilot Ratio on Counterbalance Valves

For CBEY-LAN and CBGY-LAN, verify the 2:1 pilot ratio as part of the replacement process. A similar-looking counterbalance cartridge with a different pilot ratio can produce significantly different load-control behavior.

Do Not Treat MWEM/MWGM as Relief Valves

MWEM-XIN and MWGM-XIN are explicitly non-relieving. Their flow is controlled by pilot pressure, so commissioning should be based on load pressure and pilot-pressure behavior rather than conventional relief-valve cracking pressure.

Validate Replacement Units Under Simulated Working Conditions

For replacement cartridges, recommended factory testing includes working pressure, flow response, pilot pressure, back pressure, repeated cycling, internal leakage and external sealing. This supports a reliable 100% simulated working-condition testing program for industrial replacement applications.