Page 6 - Submittal Form - For Sizing

SPM Duplex Automatic Models
SPM Duplex Automatic units consist of two SPM
Series Pump/Motor assemblies and an electrical
control panel. They are designed for use in maintained
pressure supply systems
If system pressure falls
below a preset level, the control automatically switches
from the primary pump/motor unit to the secondary
unit. If the backup pump/motor unit also fails to reach
or maintain preset system pressure, the control also
shuts off the backup unit.
A pump selector switch allows the two pump/motor
units to be manually alternated for even wear on each
pump. Pump pressures can be set at a range from 20
PSI to 85 PSI. See Correct Supply Line Size charts for
maximum discharge head.
Units should be set for two pipe operation. Preferred
installation calls for a separate suction line from tank to
pump for each pump/motor unit. If system failure
occurs because of a gross leak in the suction line of
the primary unit, the second unit can still provide
backup service.
The correct suction line size can be determined by
referring to the line sizing charts. Generally, the return
line should be sized the same as the suction line. Low
pressure drop, swing type check valves can be
installed in the suction lines, assuring that pumps are
full of oil, ready for service. Check valves in return
lines allow removal of inactive pump for servicing. Use
of shutoff valves in return lines is not recommended.
Be certain all plugs and connections are secure
and leak-tight.
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