Page 103 - Webster Service Manual

Pump/Motor Units
Available in flow rates from 430 GPH through 1730
GPH. Systems can be designed for single phase
V, 60 or 50CY , or three phase
V, 60 or 50CY , applications. The SPM
duplex models consist of two pump and motor assem-
blies with a pre-piped common discharge manifold. One
pump operates continuously, with the second providing
backup services if the main pump fails. Either automat-
ic (SPM-DA models) or manual (SPM-DM models) con-
trols 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 or industrial
buildings. The duplex pump set has a second pump for
standby or auxiliary service. Furnished with automatic
or manual standby controls, the duplex automatic is
equipped with a pressure sensing device which detects
loss of pressure of primary pump. If standby pump is
brought into service, an alarm sounds which indicates
malfunction in primary 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 pump wear . The manually operated
duplex pump sets offer the same protection as the auto-
matic except the standby pump must be turned on man-
ually which requires that maintenance personnel always
be available.