Syn-Tech Systems FuelMaster FMU-2500 Classic Installation Manual page 87

If 50 amp solid state relay assemblies (SSRA) were used to control the two solenoid valves and
one SUBMERSIBLE STARTER (or a single anti-siphon valve), LD1 and LD2 would be tied
together either with a jumper, or at the SUBMERSIBLE STARTER. This wouldn't work as an
authorization signal would activate both solenoid valves when only one was authorized.
Figure 4-12 illustrates control of a dual hose, single product dispenser having two solenoid
valves and one SUBMERSIBLE STARTER. If the dispenser had two SUBMERSIBLE
STARTERs, there would be individual wires from the DCRA to each starter. A wire would be run
from 1B to hose 1 SUBMERSIBLE STARTER, and another wire from 2B to hose 2
SUBMERSIBLE STARTER.
This application may also be used to control a dual hose dispenser with two suction pump
motors (no internal solenoid valves) and a solenoid controlled anti-siphon valve which must be
activated when either motor is turned on. In Figure 4-12, this would be illustrated by substituting
suction pump motors where the solenoid valves are, and a solenoid controlled anti-siphon valve
where the SUBMERSIBLE STARTER is shown.
Perform the following to control two devices using DCRA:
1) Inside the dispenser junction box, locate the RESET COMPLETE wire feeding the solenoid
valve for hose 1, and the SUBMERSIBLE STARTER. The wire to the solenoid valve is most
likely an orange wire. The wire to the starter is most likely a red wire. These wires will be
wire-nutted to an AC input to the solenoid valve and starter, respectively. There should be
power present on both wires when the dispenser pump handle is turned on, and power
should be removed when the pump handle is turned off.
2) Remove dispenser power at the circuit breaker panel.
3) Run three wires from the FMU to the dispenser junction box.
4) In the FMU, connect one wire to LN1, the second to LD1, and the third to 1B on the terminal
strip on the DCRA.
5) Run a jumper wire from LD1 to 1A on the terminal strip on the DCRA.
6) In the dispenser, disconnect the RESET COMPLETE wirew found in step 1) from the
solenoid valve and starter.
7) Connect the wire running from LN1 to the orange RESET COMPLETE wire.
8) Connect the wire running from LD1 to the VALVE HOT wire.
9) Connect the wire running from 1B to the L1 contact of the SUBMERSIBLE STARTER.
10) Repeat steps 1 through 9, as required, for all additional hoses. For the wiring diagram
shown in Figure 4-12, with one starter, run a jumper wire from 1B to 2B. This will provide for
an output to the starter when an input is received on 2A.
e. Two-Stage Valve Control. See Figure 4-13. Two-stage valve control is a control method for
separately controlling the fast and slow stages of a two-stage valve. Two-stage valve control is
used 1) to ensure preset quantities or costs are not exceeded, and 2) to reduce shutdown
pressure at the end of the transaction in systems with high flow rates.
Control is accomplished by turning on both the fast and slow valves at the same time, then
turning off the fast valve and ending the transaction with the slow valve. This significantly
reduces the flow rate and allows for the transaction to end without overrunning the preset
amount, and without a high pressure shock to the mechanical pumping components.
Two relay assemblies are used to accomplish two-stage valve control. This limits the maximum
number of possible hose controls to four. An option in the firmware must be turned on to enable
two-stage valve control. The point at which the fast valve turns off before the slow valve is called
the setpoint. The setpoint may be set to any value between 0.1 and 10.0 units (dollars or
gallons). Additional explanation for retail functions associated with two-stage valve control are
covered in Appendix E.
FuelMaster
®
Installation Manual
85