Installation manual

FuelMaster
®
Installation Manual
52
constant. It should be power applied when a pump handle or pump switch is turned on. When this
power source is found, find a convenient place to break the connection. There will usually be a wirenut
connection that may be separated. Use the FMU LN and LD positions as switch contacts to control
power to the valve or motor. Attach the incoming power for the valve or motor to a wire routed to an
FMU LN position (LN1 for hose 1, LN2 for hose 2, LN3 for hose 3, etc.). Run a wire from the
corresponding FMU LD position back to the valve or motor. The end result should provide for a
switched power line in the dispenser routed to an FMU LN position, and an FMU authorization output
from LD routed back to the valve or motor. When an authorization signal is sent from the FMU, the
valve or motor is turned on.
If the wire routed to LN carries power that gets hot when the pump handle or pump switch is turned
on, that power source may be used for pump handle detection on LN.
CAUTION
Dual Control Relay Assemblies cannot handle current loads in excess of 2 amps. Motors may not be
controlled directly. Use relays/motor contactors to control motors with Dual Control Relay Assemblies.
ATTENTION
Dual Control assemblées relais ne peut pas manipuler des charges en cours de plus de 2 ampères.
Motors ne peut pas être contrôlée directement. contacteurs relais usage mécanique / moteur pour
commander les moteurs lors de l'utilisation Dual Control assemblées relais.
If desired, both solenoid valves and pump motors may be controlled by the FMU. The most practical
application is through the dual control relay assembly. The LN and LD positions on the Pedestal I/O
Board may be used to control the solenoid valves, and the A and B positions (1 through 4) of the
terminal strip on the dual control relay assembly may be used to control the pump motor. Although it is
possible to use solid state relay assemblies to control both solenoid valves and pump motors through
the LN and LD positions of the Pedestal I/O Board, use caution when selecting your application.
Where the dual control relay assembly has separate outputs for the pump motors (A and B positions),
a solid state relay assembly has to share the LN and LD positions. If a dual hose single product
dispenser is being controlled, there will be a single pump motor. If you wired an output from LD1 and
LD2 to a single pump motor, and started a transaction by selecting only hose 1, the output from LD1
to the pump motor would backfeed to LD2 and authorize hose 2. Product could then be pumped from
hose 2 without selecting it, and without accountability of the product being dispensed.
Controlling Two-Stage Valves: when a credit card transaction is “preset” with a specified quantity
or cost total, the fast and slow segments of two-stage valves are separately controlled to ensure the
transaction ends at the specified quantity or cost amount. This is accomplished by using two relay
assemblies: the first to control the slow valve, the second to control the fast valve. Both valves are
opened simultaneously. The fast valve is turned off at the “setpoint”. The slow valve is used to finish the
transaction.
Because two relay assemblies are used, the maximum number of hoses which may be controlled are
reduced to four. Options in the FMU firmware must be set to enable two-stage valve operation, and to set
the “setpoint”. More detailed information for retail self-service operations monitored by Weights and
Measures may be found in Appendix E.
Using the FMU to automatically remove pump power: there are some fueling systems or
scenarios that do not require the fueling customer to turn off a pump handle to hang the fuel nozzle
back up. As such, the pump motor may not get turned off when the transaction is finished. Some
pump motors may be damaged if left to run for extended periods, particularly motors on aboveground
tanks exposed to direct summer sunlight. This may be prevented by planning control wiring so the
FMU automatically removes pump power if the fueling customer does not turn off the pump handle or
pump switch.
Authorization power from the FMU LD positions will time out if the pump handle or pump switch is not
turned off. If motor power is derived from the LD positions, the power will time out and turn off at the
end of the Pump Finish Timer setting. This is regardless of whether pump handle detection is wired in
or not. Give careful consideration to wiring pump power to FMU LD positions.
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