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NPSHA=Ha-Hs-Hf-Hv-Hst (in meters head)
Ha: Barometric pressure. (That can be set to 15 psi.)
Hs: Suction lift.
Hf: Friction loss in suction pipe.
Hv = KT+KH: Vapor pressure
KT: Flow resistance due to liquid temperature.
KH: Flow resistance due to elevation above sea level.
If the liquid is water, you can consult the tables to determine the
values of KT and KH.
T(F)
68
86
104 122 140 158 176 194 212 230 248
KT
0.7
1.3
2.6
4.3
(Ft)
H
0
1640 3280 4921 6461 8202 9842
(Ft)
KH
0
1.80 3.61 5.41 7.22 9.02 10.8
(Ft)
Hst: Safety margin. (minimum: 7 FEET head)
>
NPSHA = NPSHR: Pump running will be fine.
NPSHA < NPSHR: The pump will be dry running or cavitating.
Stop operation of the pump if cavitation
occurs. Cavitation will cause pump damage
and the resultant damage is not subject to
warranty
4.4 Minimum nominal flow rate
To prevent overheating of the internal pump components, the
pump should not be used at flows below the minimum flow
rate.
Do not run the pump against a closed dis-
charge valve for longer than a few seconds.
The curve below shows the minimum flow
rate as a percentage of the nominal flow rate
in relation to the liquid temperature.
7.2
11 16.4 24
36
4.6 Electrical data
See the motor nameplate.
Make sure that the supply voltages, phase
and frequencies correspond to the motor
specifications.
4.7 Number of starts per hour
Motors up to and including 5 HP: Maximum 100 times per hour.
Motors of 7.5 HP and up: Maximum 40 times per hour.
If you use another brand of motor then check
the manufacturer's instructions for the
maximum frequency of starts.
5. INSTALLATION
Always refer to the local or national regulations and codes relat-
ing to the selection of the installation site, the water and power
connections, etc.
49
72
5.1 Position
Pumps should be installed in a protected environment – not
exposed to weather. Make sure that there are no obstructions to
prevent proper motor cooling.
5.2 Anchoring
The pump must be secured to a solid foundation by bolts
through the holes in the flange or base plate. An illustration of
page 9 shows the bolt location and the pipe connections.
5.3 Installation example
When positioning and installing the pump, follow the installation
examples next page in order to avoid damaging the pump.
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