3V/4V External Pilot

The characteristic of 3V/4V external pilot solenoid valve is that 3V/4V solenoid valve body structure is  complex, requiring a separate external control air source to be introduced into the valve body. The positions of the pneumatic control vary among different brands, with some located on the pilot head. OLK feature an air inlet at the P-port of the valve body, which is externally connected to a port to actuate the spool. This design allows operation under extremely low pressure or even vacuum conditions, making it suitable for applications with unstable air supply, vacuum environments, or low-pressure systems requiring additional control sources—such as vacuum equipment, low-pressure pneumatic cylinders, or explosive atmospheres.

For 3V external pilot solenoid valve , the external pilot inlet ports are categorized into front pilot and rear pilot based on their positions on the valve body. The advantage of rear piloting is that it offers more space and a cleaner appearance, avoiding overly tight proximity to the solenoid coil.

Feature:  An additional control air source is needed in vacuum or low-pressure systems.

Note:

The pilot port must be connected to a positive pressure air source!

The inlet can be connected to negative pressure for control.

Air supply is required for switching direction.

FAQs:

What is the pilot air port size for OLK brand  3V/4V external pilot solenoid valves?

The most pilot port size for both 3V and 4V is M5.

3V/4V solenoid valve 400 series is G1/8.

In what applications can 3V/4V external pilot solenoid valves be used?

Due to the need for an external control air source, external pilot solenoid valves can be used in vacuum equipment, low-pressure pneumatic cylinders, and explosive environments