Flow Control Valve - Wayne Vista Series Service

5.2.

FLOW CONTROL VALVE

This section describes the operation of the Wayne 2-stage solenoid operated diaphragm
valve.
The 2-stage solenoid operated diaphragm valve has three basic functions. It controls all
flow through the dispenser. It acts as a check valve to hold the dispenser full of product
between sales. And it acts as a pressure relief valve to relieve built up pressure in the
dispenser.
The valve itself consists of three main parts:
• The diaphragm valve
• The actuator
• The actuator coils
The diaphragm valve is the main flow valve. It controls the full flow through the dis-
penser. In addition, it acts as a pressure relief valve in the event that pressure builds up
downstream from the valve.
The actuator is an electrically operated solenoid valve. It controls the diaphragm valve
by switching the diaphragm into and out of full flow.
The actuator coils control the actuator itself. When the coils are energized "poppets"
inside the actuator are moved to expose flow paths through the actuator.
Together these three parts will be referred to as the "flow control valve" throughout this
section.
The flow control valve performs three separate functions. It provides for slow product
flow, to be used in the slowdown at the end of preset sales. It allows for full product
flow. It also acts as a check and pressure relief valve to hold the dispenser full of product
at all times and to relieve any excess pressure built up in the dispenser.
In all Wayne dispensers using the 2-stage solenoid operated diaphragm valve the general
order of operation is the same. At the outset of a sale the slow flow coil only is energized
causing slow product flow to start. After a small amount of product is delivered both
coils are energized. This initiates full flow. For preset sales the dispenser will switch
back to slow flow at a pre-determined point.
26
Part No. 917543 Rev. A November 1992