Suction restrictions can place stress on the diaphragm that may result in premature
failure.
Refer to Appendix II for procedures for the calculation of suction pressure.
4.4 DISCHARGE PRESSURE REQUIREMENTS
All PULSAR Metering Pumps are designed for continuous service at the rated discharge
pressure. If system suction pressure were to exceed system discharge pressure (a condition
sometimes described as “pumping downhill”), flow would be generated in addition to that
caused by the pump, resulting in a reduction in accuracy and loss of control over the metering
process. To prevent this condition, commonly referred to as “flow-through”, discharge pressure
must exceed suction pressure by at least 0.35 Bar (or 5 psi). This can be achieved where
necessary by the installation of a backpressure valve in the discharge line.
Discharge systems should be protected from excessive pressures by utilizing a pressure relief
or pressure limiting valve in the piping system. Operation of the pump at pressure above its
nameplate rated maximum may result in damage to the pump components and/or unsafe
system conditions.
Refer to Appendix II for procedures for the calculation of discharge pressure.
4.5 AUTOMATIC CONTROL (DLC, DLCM OR MPC)
Pumps equipped with the electronic controllers are provided with separate instructions. Refer to
DLC manual IOM-CTL-DLC-2005, DLCM manual IOM-CTL-DLCM-2004, or MPC manual IOM-
MPC-0104. Perform all DLC, DLCM or MPC installation procedures prior to pump startup.
4.6 PULSALARM LEAK DETECTION ELECTRICAL
CONNECTIONS
Figure 9
If equipped with an optional pressure switch, install electrical wiring and conduit in accordance
with local electrical codes.
The switch is rated as follows:
30 VDC or 125 VAC 1 Ampere Resistive.
The switch is the SPDT (single pole, double throw) type and can therefore be connected to
either open or to close upon detection of diaphragm leak condition. Contacts or wires are
identified as follows:
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