Pump Performance - Grundfos ALPHA1 L Instrucciones De Instalación Y Funcionamiento

7.5 Pump performance

7.5.1 Relation between pump setting and pump performance
Figure 18 shows the relation between pump setting and pump
performance by means of curves.
H
Fig. 18 Pump setting in relation to pump performance
Setting Pump curve
Constant curve or constant
I
speed I
Constant curve or constant
II
speed II
Constant curve or constant
III
speed III
Proportional-pressure curve
Constant-pressure curve
14
I
Function
The pump runs at a constant speed and consequently on a constant curve.
At speed I, the pump is set to run on the minimum curve under all operating conditions. See
fig. 18.
The pump runs at a constant speed and consequently on a constant curve.
At speed II, the pump is set to run on the intermediate curve under all operating conditions.
See fig. 18.
The pump runs at a constant speed and consequently on a constant curve.
At speed III, the pump is set to run on the maximum curve under all operating conditions.
See fig. 18.
Quick venting of the pump can be obtained by setting the pump to speed III for a short
period.
The duty point of the pump will move up or down on the proportional-pressure curve,
depending on the heat demand in the system. See fig. 18.
The head (pressure) is reduced at falling heat demand and increased at rising heat demand.
The duty point of the pump will move out or in on the constant-pressure curve, depending on
the heat demand in the system. See fig. 18.
The head (pressure) is kept constant, irrespective of the heat demand.
III
II
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