NFDC-LAN NCEB-LCN CSAD-XXN RPKC-LAN Sun Hydraulic Cartridge Valve 350 bar

Product Overview

This SUN series screw-in cartridge valve portfolio covers four core models: NFDC-LAN, NCEB-LCN, CSAD-XXN, and RPKC-LAN. These products span three major functional categories — flow control, motion control, and pressure control — delivering comprehensive cartridge valve solutions for hydraulic systems.

• NFDC-LAN: Fully adjustable needle valve (throttle) with no pressure compensation, designed for bi-directional infinite flow regulation and shut-off functionality.

• NCEB-LCN: Pilot-assisted counterbalance valve for motion control and load-holding applications, featuring an external drain configuration.

• CSAD-XXN: Single-ball shuttle valve with signal at port 2, connecting the higher of two work ports to the signal/common port.

• RPKC-LAN: Pilot-operated, balanced-piston relief cartridge for precise pressure regulation and system overpressure protection.

All models feature screw-in cartridge construction for direct installation into standardized cavities, offering convenient assembly and low maintenance costs.

As a high-performance alternative to genuine Sun Hydraulics series products, this portfolio delivers full performance parity with Sun original specifications, featuring 100% form-fit-function interchangeability — cavity dimensions, installation torque specifications, and performance parameters are identical to the original, enabling direct replacement without manifold modifications. Every unit undergoes 100% simulated in-service testing prior to shipment, ensuring proven reliability under real-world operating conditions.

Technical Specifications 

NFDC-LAN — Fully Adjustable Throttle Valve (Needle Valve)

• Product Type: Fully adjustable needle valve (non-pressure compensated)

• Cavity: T-5A

• Maximum Flow: 45 L/min (6.4 mm orifice diameter)

• Maximum Operating Pressure: 350 bar

• Adjustment: Infinitely adjustable from fully closed to maximum orifice diameter

• Flow Direction: Bi-directional (1→2 / 2→1)

• Seal Material: NBR / FKM (optional)

• Body Material: Stainless Steel / Carbon Steel

• Hydraulic Fluid: Mineral oil (per DIN 51524)

• Temperature Range: -20℃ to +80℃

NCEB-LCN — Pilot-Assisted Counterbalance Valve

• Product Type: Pilot-assisted counterbalance valve with reverse-flow check

• Cavity: T-11A

• Series: Series 1

• Maximum Flow: 45 L/min

• Maximum Operating Pressure: 350 bar

• Valve Type: Normally closed

• Drain Configuration: External drain (ensures consistent operation regardless of port 2 back pressure)

• Seal Material: NBR / FKM (optional)

• Body Material: Stainless Steel / Carbon Steel

• Hydraulic Fluid: Mineral oil

• Temperature Range: -20℃ to +80℃

• Leakage at 110 SUS (24 cSt): 0.7 cc/min

CSAD-XXN — Single-Ball Shuttle Valve

• Product Type: Single-ball shuttle valve with signal at port 2

• Cavity: T-11A

• Series: Series 1

• Maximum Flow: 10 L/min

• Maximum Operating Pressure: 350 bar

• Valve Element: Hardened steel ball and seats

• Valve Hex Size: 7/8 in. (22.2 mm)

• Installation Torque: 30 – 35 lbf·ft (41 – 47 N·m)

• Weight: 0.25 lb (0.11 kg)

• Leakage at 110 SUS (24 cSt): 5 drops/min (0.3 cc/min)

• Seal Material: Buna-N (NBR) / EPDM / Polyurethane / Viton (FKM)

• Body Material: Steel

• Hydraulic Fluid: Mineral oil (EPDM seals for phosphate ester fluids)

• Temperature Range: -20℃ to +80℃

RPKC-LAN — Pilot-Operated Relief Valve

• Product Type: Pilot-operated, balanced-piston relief cartridge

• Cavity: T-18A

• Series: Series 4

• Maximum Flow: 200 GPM (760 L/min)

• Maximum Operating Pressure: 350 bar (5000 psi)

• Nominal Diameter: 15 mm

• Rated Flow: 30 L/min

• Valve Type: Pilot-operated, balanced-piston construction

• Control Mode: Hydraulic

• Body Material: Steel

• Hydraulic Fluid: Mineral oil

• Oil Temperature: 45℃

Key Technical Advantages

1. Sun Floating-Style Construction — Low Sensitivity to Installation Torque

The most distinctive technical advantage of Sun cartridge valves is the floating-style construction — the working assembly floats within the valve body, significantly reducing sensitivity to installation torque and preventing internal binding caused by excessive torque or cavity machining variations. This design dramatically improves field installation success rates and long-term operational reliability.

2. Standardized Cavity Design — 100% Interchangeability

NFDC-LAN (T-5A), NCEB-LCN (T-11A), CSAD-XXN (T-11A), and RPKC-LAN (T-18A) all utilize Sun-standard threaded cartridge cavities. All models are fully interchangeable with genuine Sun products, enabling seamless replacement without manifold modifications — substantially reducing system retrofit and maintenance costs.

3. High-Performance Sealing with Ultra-Low Leakage

• CSAD-XXN: Hardened steel ball and seat construction delivers leakage as low as 0.3 cc/min at 350 bar

• NCEB-LCN: Leakage of only 0.7 cc/min at 110 SUS

• NFDC-LAN: Tapered seat sealing design achieves zero-leakage shut-off in fully closed position
  Multiple seal material options (NBR, FKM, EPDM, Polyurethane) accommodate diverse hydraulic fluids and operating conditions.

4. Broad Flow and Pressure Coverage

The portfolio covers an exceptionally wide flow range — from 10 L/min (CSAD-XXN shuttle) to 760 L/min (RPKC-LAN relief), with a unified maximum operating pressure of 350 bar. Whether for low-flow signal sensing or high-flow system pressure protection, a suitable model is available.

5. Multi-Function Integration — One Valve, Multiple Functions

• NCEB-LCN: Integrates counterbalance, load-holding, anti-cavitation, and thermal relief protection in a single valve

• NFDC-LAN: Combines bi-directional throttling and shut-off valve functions

• CSAD-XXN: Integrates shuttle valve and pressure signal sensing functions

This multi-functional integration reduces the number of valve components in the system and simplifies manifold layout.

Application Areas

NFDC-LAN — Fully Adjustable Throttle Valve

• Lift speed control and smooth speed limiting for truck hydraulic tailgates

• Flow regulation and shut-off pressure-holding for small hydraulic power units

• Hydraulic circuits requiring bi-directional infinite flow adjustment

NCEB-LCN — Pilot-Assisted Counterbalance Valve

• Smooth controlled lowering of overrunning loads (booms, arms, etc.)

• Cylinder position holding and load-locking

• Load drop protection against hose burst failure

• Closed-loop circuits requiring thermal relief protection

CSAD-XXN — Single-Ball Shuttle Valve

• Pressure signal sensing for load-sensing pumps

• Pressure selection and signal switching in dual-pump combining circuits

• Logic circuits requiring the higher of two work port pressures to be transmitted to the control port

RPKC-LAN — Pilot-Operated Relief Valve

• Overpressure protection for main hydraulic system pressure circuits

• Precise pressure regulation in high-flow hydraulic systems

• Precision pressure control applications requiring low pressure rise vs. flow characteristics

Target Equipment: Truck hydraulic tailgates, small hydraulic power units, construction equipment (excavators, loaders), lifting equipment, injection molding machines, die-casting machines, machine tool hydraulic systems, test benches, and more.

Expert Maintenance Tips

1. Precise Installation Torque Control

Although Sun cartridge valves feature floating-style construction to reduce torque sensitivity, installation torque specifications must still be strictly followed:

• CSAD-XXN (T-11A): 30 – 35 lbf·ft (41 – 47 N·m)

• Refer to corresponding Sun installation torque specifications for other models
  Ensure threads are centered during installation to distribute thread load more evenly within the manifold.

2. Cavity and Mounting Surface Cleaning

Thoroughly clean the cavity interior and mounting surface prior to installation to remove chips, burrs, and contaminants. The shoulder stop at the bottom of the cavity supports the floating portion of the valve — ensure it is free from damage.

3. Seal Selection and Replacement

• Standard mineral oil systems: Buna-N (NBR) seals

• Phosphate ester fluid systems: EPDM seals are mandatory

• High-temperature applications: Viton (FKM) seals
  Replace all cartridge seals after every disassembly (external seals are serviceable; internal seals are not).

4. Fluid Cleanliness Management

Maintain system fluid cleanliness at ISO 4406 Class 18/16/13 or higher. Sun cartridge valves feature hardened steel balls and seats for excellent contaminant tolerance — however, installation of a ≤10μm return line filter is still recommended for long-term reliability.

5. Periodic Functional Testing

• NFDC-LAN: Test throttling smoothness and full-closed shut-off functionality every 2,000 operating hours

• NCEB-LCN: Regularly verify load-holding reliability — check for cylinder drift or actuator creep

• CSAD-XXN: Test shuttle signal switching responsiveness — check for signal delay or loss

• RPKC-LAN: Periodically calibrate relief pressure settings and check for abnormal leakage