01
3/2 valve: definition and engineering context
Three-port, two-position valve. Directional valve with three ports and two switching states.
The term belongs to the valves & circuits context. Its exact limits can depend on the cited standard, catalog convention, unit system, reference state, and component configuration.
02
Why 3/2 valve affects pneumatic selection
Common for single-acting actuators and on/off air functions.
- 5/2 valve: Common for double-acting cylinders.
- 5/3 valve: Specify closed, pressure, or exhaust center; center function changes actuator behavior.
- NC: Confirm which ports the catalog calls normally closed.
- NO: Use when the required fail-state needs flow.
03
How to evaluate 3/2 valve in a catalog or replacement project
Read the value together with its unit, test basis, operating pressure, temperature, circuit state, and manufacturer definition.
For replacement work, compare the complete datasheet and drawing. A matching abbreviation or nominal size does not by itself prove functional or dimensional interchangeability.
- Five-port, two-position valve: Directional valve with pressure, two working, and two exhaust ports.
- Five-port, three-position valve: Directional valve with a defined center state.
- Normally closed: Flow path is closed in the defined normal or de-energized condition.
- Normally open: Flow path is open in the defined normal or de-energized condition.
Selection checklist
What to verify before selection
- 01
Common for single-acting actuators and on/off air functions.
- 02
Common for double-acting cylinders.
- 03
Specify closed, pressure, or exhaust center; center function changes actuator behavior.
- 04
Confirm which ports the catalog calls normally closed.
Application caution
Common mistakes
- Treating 3/2 valve as a universal definition without checking the manufacturer or standard context
- Mixing gauge and absolute values, incompatible units, or different reference conditions in one comparison
- Selecting a component from the term or nominal value alone without checking the complete operating point and drawing
FAQ