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How to Read CETOP Directional Valve Part Numbers
CETOP is not a brand or model; it is a mounting interface. A part number also encodes function, spool pattern, coil voltage and connector. That is why “a CETOP 3 valve” can mean dozens of products, and why orders fail when these levels are confused.
This guide reads the code in blocks: size, function, centre condition and electrics. At the end are three real part numbers and the information needed for an accurate quotation.
CETOP 3, 5, 7 and 8: four sizes
CETOP 3 is NG6, CETOP 5 is NG10, CETOP 7 is NG16 and CETOP 8 is NG25. ISO 4401 defines the mounting dimensions, so different makers often share a subplate. The standard does not guarantee function, flow or electrics.
| CETOP | NG | ISO 4401 | Typical flow | Usual application |
|---|---|---|---|---|
| CETOP 3 | NG6 | 03 / D03 | 40–60 l/min, some versions to 80 | Small mobile equipment, machine tools, auxiliary circuits |
| CETOP 5 | NG10 | 05 / D05 | 80–120 l/min, some versions to 150 | Medium systems, presses, construction equipment |
| CETOP 7 | NG16 | 07 / D07 | 200–300 l/min | Heavy mobile machinery, industrial drives |
| CETOP 8 | NG25 | 08 / D08 | 400–600 l/min | High-flow systems, large presses, power units |
These flows are a guide, not a catalogue maximum. Capacity depends on pressure drop, viscosity and spool profile. A valve near its limit may overheat the oil and slow the cylinder. Check the Δp curve, not just the headline figure.
Our catalogue includes hydraulic valves and hydraulic distributors. If you are sizing a pump for the required flow, start with hydraulic pumps.
Function first: 4/3, 4/2, 3/2 and 2/2
“4/3” means four ports (P, T, A, B) and three positions. The first number is the number of lines, the second the number of positions. For a 4/3 valve, the centre condition matters just as much.
| Function | What it means | Typical use | What to check |
|---|---|---|---|
| 2/2 | 2 ports, 2 positions | Shut-off, bypass, simple flow | NO/NC; pressure rating |
| 3/2 | 3 ports, 2 positions | Single-acting cylinder, pump unloading | P–A–T; spring return |
| 4/2 | 4 ports, 2 positions | Double-acting cylinder, no mid-position | End position; spool stroke |
| 4/3 | 4 ports, 3 positions | Double-acting cylinder with neutral | Centre; load holding |
A common mistake is to assume 4/3 means a closed centre. In neutral, the spool may block every line, connect P to T, or let the cylinder float. These behave very differently in safety and heat terms.
Centre conditions: closed, tandem, float and open
The centre condition decides what happens when both coils are de-energised. It is also the detail most often missed when replacing a “same” valve.
| Centre | Neutral state | Pump | Actuator |
|---|---|---|---|
| Closed | P, T, A and B blocked | Deadheads without an unloading path | Holds position; oil may overheat |
| Tandem | P to T; A, B blocked | Unloads to tank | Holds position |
| Float | P blocked; A, B to T | Needs separate unloading | Does not hold load; rod can move |
| Open | P, T, A and B connected | Unloads | Does not hold; used in simple circuits |
Names and symbols vary. Check which lines connect in the centre position, not just the label “closed” or “tandem”. With a fixed pump and no unloading valve, a closed centre is a poor choice: oil heats through the relief valve.
Coil voltage, connectors and options
Electrical data matters as much as hydraulics. A 24 V DC coil will not run on 230 V AC, and the wrong connector stops commissioning.
| Parameter | Typical options | What to check |
|---|---|---|
| Voltage | 12 or 24 V DC; 110 or 230 V AC | Coil code, voltage tolerance, rectifier for AC |
| Connector | DIN 43650 / EN 175301-803, M12, Deutsch, AMP, leads | Mating plug, IP rating, cable length |
| Power | Typically 20–30 W for NG6 | Current, inrush, duty cycle |
| Options | Manual override, LED, surge suppression, position switch | Whether the machine needs them |
24 V DC is common in mobile hydraulics, but not automatic. Check the vehicle supply, voltage drop on long cables and the mating connector. AC coils sometimes need a rectifier in the plug, so confirm what is included.
Three part numbers, block by block
Rexroth: 4WE6E-6X/EG24N9K4
This is a standard NG6 solenoid directional valve. The blocks read:
| Block | What it usually means |
|---|---|
| 4WE | Four-way solenoid directional valve |
| 6 | Size NG6 / CETOP 3 |
| E | Spool version; check the centre symbol |
| 6X | Design generation |
| EG24 | 24 V DC coil |
| N9K4 | Options and connector; content depends on generation |
E is not a universal code for a closed centre. At Rexroth it identifies one spool version; verify the pattern in the catalogue and nameplate. Do not apply this logic to other brands.
Danfoss: DG4V-3-2A-M-U-H7-60
DG4V-3 is a four-way CETOP 3 valve; 2A is the spool and return code. The rest covers coil, connector and generation, depending on the series. Reading them as Rexroth codes will order the wrong valve.
Hansa Flex
Hansa Flex is a distributor, so its catalogue may show an internal number, not the maker’s full code. Look for CETOP 3 / NG6, maker and spool type. If only an internal number exists, send photos of the nameplate and mounting face; this narrows the search but does not replace the function data.
What to send for an accurate quote
- CETOP size, or the mounting-face dimensions.
- Function (4/3, 4/2, etc.) and centre condition.
- The complete part number from the nameplate.
- Coil voltage, connector and manual override.
- Flow, pressure, fluid and operating temperature.
- Quantity and required delivery date.
If the number is unreadable, photograph the valve from above and the side, measure port spacing and send the circuit diagram. This may identify a replacement, but takes longer.
Frequently asked questions
Is CETOP 3 the same as NG6?
Yes. They describe the same mounting interface, also known as ISO 4401-03 or D03. But function, flow, pressure and electrics must also match.
Can I replace a 4/3 valve with a 4/2?
Only if the circuit does not use neutral or hold a load. Otherwise it changes machine logic and may create a safety risk.
What does the E mean in 4WE6E?
A Rexroth spool version. It is not universal and does not guarantee a centre condition; check the catalogue symbol.
Can I fit a 230 V AC coil in place of 24 V DC?
No. Coil, connector and sometimes the rectifier must match the supply. The wrong coil can damage the wiring.
Need help decoding a part number?
Send a nameplate photo, the spool symbol and the flow and voltage data. We will check the machine and propose a compatible replacement.
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