SUNTEC A-3000B model contains a unique and hydraulic dual safety cut-on/off driven by a motor speed dependent device and a solenoid by-passing valve
As the motor starts, the fuel from the gearset flowing through the cone valve creates a pressure drop across the diaphragm valve. When the pressure difference is sufficient to overcome the spring force, the diaphragm valve closes and the fuel is routed to the piston chamber.
If the solenoid valve (Normally Open) is :
Opened (de-energized), the fuel flows through the by-pass channel, no pressure will then be built up. The piston will not release the fuel flow through the nozzle.
Closed (energized) and the diaphragm valve is closed, the pressure is built up causing the piston to open and the fuel flow through the nozzle.
The piston spring is adjusted such that a given nozzle pressure can be maintained while any resulting excess fuel is dumped.
When the solenoid valve is open (de-energized), the valve opens, closing the piston at full operating speed, shutting fuel off the nozzle.
One pipe installation :
The by-pass plug must not be installed. The excess fuel is returned back to the inlet.
Two pipe installation :
The steel plug of the return port must be removed and the by-pass plug must be inserted in the return port allowing excess fuel is bypassed back to the tank. The return plug must not be reinstalled.
In one pipe operation, the easy flow bleeder valve must be loosened to bleed the system.
Bleeding in two pipe operation is automatic, but it may be accelerated by loosening the easy flow bleeder.