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DESMI Pumping Technology A/S
14
Tagholm 1
9400 Nørresundby – Denmark
Tel: +45 96 32 81 11 Fax: +45 98 17 54 99
E-mail:
10. SYSTEM BALANCING
It is often difficult to calculate a manometric delivery head in advance. It is, however,
decisively important to the quantity of liquid delivered. A considerably smaller delivery head
than expected will increase the quantity of liquid delivered, causing increased power
consumption and perhaps cavitation in pump and piping. In the pump the impeller may show
signs of heavy erosion caused by cavitation (corrosion) which may at times render an impeller
unfit for use in a very short time. Not unusually do similar erosions occur in pipe bends and
valves elsewhere in the piping system.
Therefore, after start-up, it is necessary to check either the quantity of liquid delivered or the
power consumption of the pump e.g. by measuring the current intensity of the connected
motor. Together with a reading of the differential pressure the quantity of water delivered can
be determined against the characteristics of the pump.
Should the pump not function as intended, please proceed according to the fault-finding list.
Bear in mind, though, that the pump was carefully checked and tested at the factory and that
the majority of faults stem from the piping system.