Product Description

CKD 4RD139-GS4-E2-3 — 4RD Series 5-Port 3-Position Pilot Operated Solenoid Valve

Pneumatic control valves are rarely noticed when they're working well — and that's the point. The 4RD139-GS4-E2-3 from CKD is built around exactly that philosophy: a compact, low-power, long-life 5-port pilot operated valve that installs cleanly, operates reliably, and stays out of the way of everything else in the system. Part of the CKD 4RD Series — developed through the fusion of Japanese design precision and cost-efficient manufacturing — this valve delivers the essentials of high-cycle pneumatic directional control at a fraction of the cost of premium series equivalents.

New original. In stock. Ready for immediate worldwide dispatch.

Model Number Decoded

Code Position	Code	Meaning
Series	4RD	Simple & Compact 5-Port Pilot Operated Valve Series
Body Type	4RD1	10mm wide, body piping type
Valve Positions	3	3-position, all ports closed (mid-stop)
Variant	9	Body piping configuration variant
Port A/B	GS4	Push-in fitting, tube outer diameter φ4
Electrical Connection	E2	E-connector, 300mm lead wire
Voltage	3	DC 24V

Technical Specifications

Parameter	Value
Series	CKD 4RD Series (4RD/M4RD)
Model	4RD1 — 10mm wide, body piping
Valve Type	5-port, pilot operated, soft spool
Valve Positions	3-position, all ports closed
Port P / R1 / R2 Size	M5
Port A / B Size	Push-in fitting φ4 (GS4)
Electrical Connection	E-connector with 300mm lead wire
Rated Voltage	DC 24V
Voltage Fluctuation Range	±10%
Power Consumption	0.4W (standard)
Holding Current	0.017A
Max. Working Pressure	0.7 MPa
Min. Working Pressure	0.2 MPa
Proof Pressure	1.05 MPa
Effective Cross-Sectional Area	3.5 mm² (3-position)
Response Time (3-position)	30 ms or less
Pilot Method	Internal pilot, main valve exhaust type
Manual Override	Non-locking type
Weight	Approx. 64g (E-connector, 3-position)
Ambient Temperature	−5 to +55°C (no freezing)
Fluid Temperature	5 to +55°C
Working Fluid	Compressed air
Lubrication	Not required
Protection Degree	Dustproof
Vibration / Shock	50 m/s² or less / 300 m/s² or less
Durability	Over 50 million cycles
Surge Suppressor	Equipped as standard
Indicator Lamp	Standard (with indicator lamp option)
Thermal Class	Class B
Compatible Cylinder Bore	φ6 to φ100

The 4RD Series: Simple, Compact, Cost-Effective

CKD designed the 4RD Series with a single governing principle: achieve the core performance of the established 4G Series at approximately 40% lower cost, without sacrificing the fundamentals of pneumatic reliability. The result is a valve family that covers cylinders from φ6 to φ100, handles working pressures up to 0.7 MPa, and runs continuously without lubrication — in a 10mm-wide (4RD1) body that fits tightly into dense manifold layouts.

The 4RD1's body-piping design integrates the air passages directly into the valve body rather than routing through a separate sub-plate. This eliminates the sub-plate as a separate procurement and assembly item, reduces the number of leak points in the pneumatic circuit, and simplifies installation in space-constrained machine frames where sub-plate mounting would add depth or complicate access.

An air intake filter is built into ports A and B as standard on the 4RD body-piping type — a detail that protects the spool and seal surfaces from airborne contaminants in compressed air systems running without inline filtration at the valve bank.

3-Position, All Ports Closed: What It Means in Practice

The GS4 port code indicates push-in fittings sized for φ4 OD tubing at ports A and B — the same tube diameter widely used in small-bore cylinder circuits and compact manifold assemblies. Push-in connection at the work ports removes the need for threaded fittings and simplifies tube routing in tight valve-to-actuator installations.

A 3-position valve holds three distinct states: energize solenoid A, energize solenoid B, or de-energize both. In the all-ports-closed center position, supply (P), both work ports (A and B), and both exhaust ports (R1/R2) are all sealed simultaneously. When neither solenoid is energized, no air flows in any direction and the cylinder is locked in whatever position it currently occupies.

This center condition is distinct from the two other common 3-position configurations — pressure-center (P connected to A and B, R blocked) and exhaust-center (A and B connected to R, P blocked). All-ports-closed is chosen when the application requires the cylinder to hold position under load without relying on the mechanical load to maintain position against a floating exhaust circuit. Typical use cases include:

Clamp and hold operations where the cylinder must maintain clamping force during power-off or between cycles
Intermediate positioning where the actuator needs to stop and lock at a mid-stroke point
Safety-critical sequences where uncontrolled movement during a solenoid de-energized state would create a hazard
Press and forming operations where the tooling must be held in contact during the process dwell

Low Power, Long Life

The 0.4W power consumption of the standard DC 4RD coil is a meaningful figure in multi-valve manifold applications. A 10-station manifold with all valves energized simultaneously draws 4W total from the 24V DC supply — a load that fits easily within the current budget of most PLC output modules and distributed I/O systems without requiring a dedicated valve power supply.

CKD's durability target for the 4RD Series under their test conditions is over 50 million cycles. On a cycle rate of one actuation per second — a demanding pace for pneumatic sequencing — 50 million cycles represents more than 578 days of continuous operation. For realistic duty cycles in assembly and material handling applications, the practical service life extends well beyond that baseline.

The surge suppressor is built into the valve coil circuit as standard, protecting PLC outputs from back-EMF spikes generated when the coil de-energizes — an important detail when the valve is driven directly from transistor output cards without external suppression components.

Valve Comparison: 4RD Series vs. CKD 4G Series

Feature	4RD Series	4G Series
Target Application	Standard automation, cost-driven	High-performance, precision
Relative Cost	~40% lower	Full premium
Max Working Pressure	0.7 MPa	0.7 MPa
Durability (CKD test)	50M+ cycles	100M+ cycles
Body Width (smallest)	10mm	10mm
Air Intake Filter	Built-in (standard)	Optional
Response Time (M5, 3-pos)	≤30ms	≤12ms (2-pos, 4G1)
Lubrication	Not required	Not required

The 4RD is the right choice when cycle rates are moderate, the application doesn't demand sub-20ms response times, and project economics favor cost reduction without compromising basic reliability. The 4G Series earns its premium in high-speed, high-cycle applications where response time and rated life both matter.

Frequently Asked Questions

Q: What does the "3-position all ports closed" center condition mean for cylinder control?

A: When both solenoids are de-energized, supply pressure (P), both work ports (A and B), and both exhaust ports (R1/R2) are simultaneously sealed. The connected cylinder is hydraulically locked — it holds its current position without air flowing in any direction. This is the correct choice when the cylinder must maintain position under external load during an inactive phase, as opposed to allowing the load to drift through an unsealed exhaust path.

Q: What tube size connects to the GS4 ports A and B?

A: GS4 designates push-in fittings for φ4 OD tubing. Tube is inserted and locked without tools; a release collar allows removal. Port P, R1, and R2 on the 4RD1 body are M5 threaded.

Q: What voltage does this valve operate at?

A: The suffix -3 specifies DC 24V, the standard industrial control voltage. Power consumption is 0.4W, with a holding current of 0.017A. A built-in surge suppressor protects the driving output circuit.

Q: Is lubrication of the compressed air supply required?

A: No. The 4RD Series is designed for non-lubricated compressed air. Adding lubricant to the supply is permissible (use turbine oil ISO VG32 Class 1 if needed), but CKD specifies that intermittent or excessive lubrication can cause unstable valve operation — consistent dry air supply gives the most predictable performance.

Q: Can this valve be used on a manifold?

A: Yes. CKD offers the M4RD Series as the manifold-specific equivalent using the same valve body. Single-unit 4RD1 valves can also be assembled onto CKD manifold sub-plates for multi-station layouts. The model number encoding identifies this unit as a standalone body-piping type.

Q: What is the maximum cylinder bore this valve can drive?

A: The CKD 4RD Series is rated for compatible cylinder diameters of φ6 to φ100. For the 4RD1 size specifically, the effective cross-sectional area in 3-position mode is 3.5 mm², which corresponds to the flow requirement of cylinders up to approximately φ40 depending on cycle rate and stroke length.

Q: How does the E-connector wiring work?

A: The E2 connector is a DIN-style plug connector with 300mm of lead wire pre-attached. It accepts a standard DIN 43650 compatible socket for clean, tool-free wiring to the machine cabinet harness. The connector includes the integral surge suppressor and indicator lamp. If a different lead length is needed, CKD offers E20 (500mm), E21 (1000mm), E22 (2000mm), and E23 (3000mm) variants of the same connector.

Q: What does "New Original" mean for this listing?

A: The valve is factory-new, genuine CKD manufacture, in original packaging, and has never been installed, pressurized, or cycled. It is not a rebuilt, reconditioned, or counterfeit unit. Single pieces are available in current stock for immediate dispatch.

4RD139-GS4-E2-3 New Original CKD Solenoid Valve 4RD139M5E23