Installation manual

FuelMaster
®
Installation Manual
81
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8) Repeat steps 1 through 7, as required, for all additional hoses.
f. Using Dual Control Relay Assembly (DCRA) to Control Two Devices. See Figure 4-11.
Classic and DoD FMUs do not provide for control of dispenser reset while also providing pump
handle detection. If it is desired to use a classic or DoD FMU to control solenoid valves and
pump motors, and still have pump handle detection, it may be accomplished using a DCRA. The
DCRA provides an additional set of relays to control two devices with each hose selection. This
control method interrupts power from the dispenser reset mechanism to both solenoid valves
and pump motors, and allows dispenser reset without authorization, but prevents pump motor
activation until authorized. Pump handle detection is possible from all variations of FMUs.
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 4-11 illustrates control of a dual hose, single product dispenser having two solenoid
Figure 4-11. Wiring Diagram - Using Dual Control Relay
Assembly (DCRA) to Control Two Devices
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