A hydraulic directional valve model code looks like a string of letters, numbers and symbols — but every position encodes a specific functional or physical characteristic. Missing a suffix can mean the difference between a valve that operates the circuit correctly and one that bolts on but works incorrectly. This guide explains how to read Rexroth 4WE and Vickers DG4V codes, what each code group controls and why guessing is expensive.
Send a hydraulic component for review: Include the complete model code, quantity, destination and available photos or drawings.
Why every character matters
Two valves from the same series can share a mounting pattern while differing in spool function, solenoid voltage, connector style, seal material or manual-override arrangement. Shortening the code to a family name hides these differences.
- A '4WE6' label describes the family and nominal size, not the spool function, voltage or connector
- A 'DG4V-3' reference gives the frame size but omits spool, centering, solenoid and seal options
- Characters are not interchangeable — a missing slash, hyphen or space may represent a real configuration difference
- Order numbers (R900…) and material numbers are separate identifiers that may carry revision information not visible in the short code
Rexroth 4WE directional valve code groups
| Code position | Example | What it controls | What to check |
|---|---|---|---|
| 4WE 6 | 4WE 6 | Directional spool valve, nominal size 6 (NG6 / CETOP 3) | Confirm mounting pattern ISO 4401-03 / CETOP 3 |
| Spool symbol | D, E, J, C, Y, etc. | Flow paths in each solenoid state and the de-energized center condition | Match the spool symbol to the hydraulic schematic — do not substitute without circuit review |
| Series | 5X, 6X, 7X | Design series; may affect dimensions, pressure rating or available options | Confirm installation dimensions are consistent across series changes |
| Solenoid type | E, G, etc. | Wet-pin DC solenoid (E) or AC solenoid (G) | DC and AC solenoids are not interchangeable; confirm voltage type and coil specification |
| Voltage | G24, W230, etc. | 24 VDC (G24) or 230 VAC 50/60 Hz (W230) | Voltage must match the machine electrical supply; wrong voltage damages the coil |
| Manual override | N9, N, etc. | Manual override type and accessibility | Confirm override is usable in the installed position |
| Connector | K4, K40, etc. | DIN connector (K4) or other connector type | Connector must match the wiring harness; K4 = DIN EN 175301-803 |
| Seals / special | V, M, etc. | FKM seals (V) for higher temperature or special fluids; NBR is standard | Match seal material to the hydraulic fluid and operating temperature range |
This structure is illustrative for the 4WE6 series. Other Rexroth valve families may follow a different code structure. Always consult the original manufacturer documentation for the exact model.
Vickers DG4V-3 directional valve code groups
| Code position | Example | What it controls |
|---|---|---|
| DG4V-3 | DG4V-3 | Solenoid-operated directional valve, size 3 (CETOP 3 / NG6) |
| Spool type | 2C, 6C, 0C, etc. | Spool function and center condition — open, closed, tandem or float |
| Spool/spring arrangement | M, etc. | Spring-offset or detent configuration |
| Voltage | U, L, etc. | Coil voltage code — the actual voltage must be checked against the coil label |
| Coil/connector | N, K, etc. | Connector and coil type combination |
| Design number | 10, 11, 20, etc. | Design revision — may affect internal parts, dimensions or interchangeability |
| Special features | S, etc. | Special seals, manual override or environmental options |
Before requesting a replacement
- Photograph the complete nameplate — not just the top line
- Record the order number or material number if it appears separately
- Photograph the connector face and mounting surface
- Note the hydraulic fluid type, working pressure and flow
- Identify the machine and application
- Explain the known failure or replacement reason
- If a character is unreadable, mark it as unknown — do not guess
Worked RFQ example
A structured RFQ separates confirmed facts from open questions.
- Confirmed from nameplate: 4WE 6 D6X/EG24N9K4, material R900561274, D spool, 24 VDC, DIN connector K4
- Confirmed from machine: working pressure 210 bar, flow 40 L/min, mineral oil ISO VG 46 at 50 °C
- To verify from supplier: proposed manufacturer, spool drawing, mounting dimensions, pressure-drop curve, seal specification
- Release condition: hydraulic, electrical and mechanical comparison accepted; differences recorded and approved
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