Symbol
What it does
Pilot air at port 12 switches the valve. Air flows from port 1 to port 2.
Pilot air off: the spring pushes the valve back. Air in port 2 escapes through port 3.
Key words
- 3/2 valve
- A valve with 3 ports and 2 positions.
- Actuator
- The part that works the valve.
- Port
- A numbered hole where a pipe joins.
- Signal
- Air sent to make the next part work.
- Pneumatic
- Worked by air.
- Pilot air
- Air that works a valve, not a cylinder.
Sources & credits: Symbols drawn to ISO 1219, as used in N5 Engineering Science. Drawings by R Stewart. Full site credits are on the credits page. R Stewart - October 2026