Vacuum controlled 3 Way Valves apply signal pressure to a diaphragm that is opposed by a spring force. When then vacuum signal force is greater (deeper vacuum = more force) than the spring force it reaches its set-point (also called “On” pressure), the internal mechanism moves and changes the pneumatic state.
The signal pressure and pneumatic circuit are completely isolated from each other.
The pneumatic circuit is normally closed, which means the supply port is closed and the output port is vented through the exhaust to the atmosphere. There is no connection available on the exhaust port.
When the valve trips, the supply is opened to the output port and the exhaust is off. The valve will remain in this state until the pressure signal drops below its reset point (also called “Off” pressure).
The difference between the “On” pressure and the “Off” pressure is defined as the Differential or Hysteresis of the valve.
Factory preset options are available. Please contact your salesperson or distributor for specifications and a custom part number.
Adjustments can be made to the switch by removing the round cover and turning the flat head screw. Clockwise adjustments will raise the Set point. Counter clockwise adjustments will lower the setpoint (on pressure). Adjusting preset 3-way valves is not recommended. Do not back out the flat head screw above flush with the body.