Grundfos Medium UPM Series Data Booklet page 14

6
Constant Pressure
The head (pressure) is kept constant, irrespective of
the heat demand.
The duty point of the pump moves out or in on the
selected constant-pressure curve, depending on the
heat demand in the system.
The Constant Pressure/power mode limits the
maximum power consumption, like formerly the
performance of standard pumps with speed selector.
At reduced flow, the head increases. When the
maximum head selected is reached, the speed of the
pump is reduced to keep this head (differential
pressure) down to zero flow.
• CP1: lowest constant-pressure curve
• CP2: intermediate constant-pressure curve
• CP3: MAX curve
• AUTO : highest to lowest constant-pressure
ADAPT
curve.
In Constant Pressure AUTO
constant-pressure control.
The AUTO function enables the pump to control
ADAPT
the performance automatically within a defined
performance range.
• Adjusting the pump performance to the size of the
system.
• Adjusting the pump performance to the variations in
load over time.
Advantages of pump control
In Grundfos Medium UPM AUTO, pump control is
effected by adapting the differential pressure to the
flow (proportional-pressure and constant-pressure
control). Unlike an uncontrolled pump, a constant-
pressure-controlled pump keeps the differential
pressure constant. A proportional-pressure-controlled
pump reduces the differential pressure as a result of
falling heat demand.
For example:
If the heat demand falls, for instance due to solar
radiation, the thermostatic radiator valves close, and,
for the uncontrolled pump, the flow resistance of the
system rises, for instance from A1 to A2.
In a heating system with an uncontrolled pump, this
situation causes a pressure rise in the system by ΔH
14
, the pump is set to
ADAPT
.
1
H
2
A
DH
2
1
Fig. 11 Uncontrolled pump
In a system with a proportional-pressure-controlled
pump operated in the proportional pressure mode, the
pressure is reduced by ΔH
2
energy consumption.
H
2
DH
2
A
2
Fig. 12 Pump operated in proportional-pressure control
mode
In a system with an uncontrolled pump, a pressure rise
often causes flow-generated noise in the thermostatic
radiator valves. With proportional pressure control, this
noise is reduced considerably.
AUTO
ADAPT
Grundfos holds a patent for AUTO
With AUTO , the control curve is automatically
ADAPT
adapted to the actual requirements of the respective
application.
If you select AUTO , the pump starts with the
ADAPT
medium proportional or constant control curve and
runs on this curve as long as a new curve will be
adapted.
The AUTO proportional pressure functionality is
ADAPT
well known from millions of installed Grundfos trade
pumps as ALPHA2 or MAGNA. The AUTO
setting continually analyses and finds the setting
where optimal comfort meets minimal energy
consumption. It automatically delivers perfect comfort
at the lowest possible energy level. It adapts to the
requirements of the heating system before reaching
the maximum pump curve and allows the pump to
adjust the proportional pressure or constant pressure
curve both up and down.
Medium UPM
1
A
1
Q
and results in reduced
1
A
1
Q
since 1995.
ADAPT
ADAPT