• Make sure this valve is of the flapper type, rather than the multiple spring type, and
that it is sized to avoid excessive friction in the suction line.
• Size the foot valve and pipe in order to maximize NPSH
A
to the pump by minimizing
suction line losses.
• When foot valves are used, or where there are other possibilities of water hammer,
close the discharge valve slowly before you shut down the pump.
Check valves
In normal applications, check valves are placed in the discharge piping. Before you use a
check valve in the suction piping, consider the added pressure drop to the pump, the
potential of water hammer, and the chance of allowing the entire pump volute to be
exposed to the discharge pressure.
4.4.4 Discharge piping considerations
Maximum velocity
Make sure that the maximum velocity in the discharge piping does not exceed 15 feet per
second (4.6 m/s). If a check valve is present in the outlet piping, this value must be
reduced.
Discharge piping and fitting sizes
System losses, life-cycle costs, and process considerations usually determine the size of
discharge piping and fittings. Some high energy pumps are sensitive to flow disturbing
devices mounted close to the pump outlet. Consult Xylem when in doubt about the
minimum required length of the straight pipe.
4.5 Pressure gauges and pump insulation
Installation and use of pressure gauges
Install properly-sized pressure gauges in both the suction and discharge nozzles in the
gauge taps. The gauges enable easy observation of the pump operation and it is easy to
determine if the pump is operating in conformance with the performance curve.
Cavitation, vapor binding, or other unstable operations cause widely-fluctuating
discharge pressure to be noted.
WARNING:
Make sure that all components are properly guarded or insulated when operating at
extremely high or low temperatures.
4 Installation
e-XC INSTRUCTION MANUAL
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