Page 74 - Webster Service Manual

The SPM duplex models consist of two pump/motor
assemblies with a pre-piped, common discharge mani-
fold. One pump/motor unit operat es continuously, with
the second providing backup service if the main pump
fails. Either automatic (SPM-DA models) or manual
SPM-DM models) controls are available.
The duplex automatic series are designed specifically
for buildings where a constant supply of oil must be
assured ... hospitals, apartment buildings, schools and
other commercial/industrial buildings
The DA Series is equipped with a pressure sensing
device which detects a loss in pressure of the primary
pump. If the standby pump is brought into service, an
alarm sounds which indicates a malfunction in the pri-
mary pump.
The electric control circuit on the duplex automatic
pump set is equipped with a lead-lag switch to permit
manual alternation of pump to provide even wear on
each pump.
The manually operated duplex pump sets of
fer the
same protection as an automat ic except the standby
pump must be turned on manually which requires that
maintenance personnel always be available.