CETOP and NG Valve Mounting Sizes Explained
CETOP number, NG size and ISO 4401 all describe the same thing: the standardized mounting interface of a hydraulic valve. Once you know the mapping, you pick valve, subplate and seal kit without a mismatch. This guide shows how to read CETOP and NG and choose the right size by flow and pressure.
View hydraulic valvesWhat do CETOP, NG and ISO 4401 mean?
CETOP was the European fluid-power body that numbered the mounting patterns for directional valves. The German NG figure (nominal size) describes the same mounting face, now defined Europe-wide in the standard ISO 4401. All three refer to the same standardized mounting face with fixed positions of the P, T, A, B ports and the fixing screws, so valves from different makers stay interchangeable.
Which size fits my flow and pressure?
Choose the size by the maximum flow rate and the working pressure. A pattern that is too small creates pressure loss and heating, while an oversized one wastes space and money. The values per nominal size are a guide; the valve datasheet with its pressure-flow curve is always binding.
- Base sizing on the peak flow of pump and consumers, not the average.
- Match working pressure plus a safety reserve to the valve's pressure rating.
- If pressure loss or heating appears, step up one size rather than throttling the valve.
How do I check the pattern and mounting?
Before mounting, the pattern, seals and screws must all match. Check the ISO 4401 code of valve and subplate, use the correct O-ring set and tighten the fixing screws crosswise to the specified torque. That keeps the sealing face flat and leak-free.
Pick the O-ring set for the size and confirm media compatibility.
Compare accessoriesFrequently asked questions
Are CETOP 3 and NG6 the same?
Yes. CETOP 3, NG6 and ISO 4401‑03 all name the same standardized mounting pattern. CETOP is the old European number, NG the German nominal size and ISO 4401 the current standard. Valves with the same code are interchangeable.
Can I fit an NG10 valve on an NG6 subplate?
No. The patterns differ in the position and number of ports and in the screws. Valve and subplate must share the same size and ISO 4401 code, otherwise the valve will not seal.
How do I find the size in the datasheet?
Look for the ISO 4401 code or the NG or CETOP figure at the top of the datasheet. The flow rate and the allowable pressure rating confirm whether the size fits your system.
Find the right size and valve
Our hydraulics specialists help with mounting pattern, size and subplate for your system.
Standardized mapping
CETOP, NG and ISO 4401 clearly lined up.
Right size
Flow and pressure matched to the nominal size.
Leak-free mounting
Pattern, seal kit and torque kept in view.
Expert advice
Hydraulics specialists support your selection.