Automatic Night-Time Duty; Constant-Curve Duty; Max. Or Min. Curve Duty; Temperature Influence - Grundfos MAGNA 2000 Serie Notice D'installation Et D'entretien

7.3 Automatic night-time duty

To be set on the control panel or with the R100, see
section 8. Setting the pump.
Once automatic night-time duty has been activated,
the pump automatically changes between normal
duty and night-time duty (duty at low performance).
Changeover between normal duty and night-time
duty is dependent on the supply-pipe temperature.
The pump automatically changes over to night-time
duty when the built-in sensor registers a supply-pipe
temperature drop of more than 18-27 °F (10-15 °C)
within approx. 2 hours. The temperature drop must
be at least 0.18 °F/min. (0.1 °C/min.).
Changeover to normal duty takes place without a
time lag when the temperature has increased by
approx. 18 °F (10 °C).

7.4 Constant-curve duty

To be set with the R100, see section 8. Setting the
pump.
The pump can be set to operate according to a
constant curve, like an uncontrolled pump, see
fig. 10.
H
Min.
Fig. 10 Operating curves

7.5 Max. or min. curve duty

To be set on the control panel*, with the R100* or via
GENI module, see section 8. Setting the pump.
The pump can be set to operate according to the
max. or min. curve, like an uncontrolled pump, see
fig. 11.
This operating mode is available, irrespective of the
control mode.
H
Min.
Fig. 11 Max. and min. curves
The max. curve mode can be selected if an
uncontrolled pump is required.
The min. curve mode can be used in periods in
which a minimum flow is required. This operating
mode is for instance suitable for manual night-time
duty if automatic night-time duty is not desired.
*Note: Max, when set from control panel or R100,
will take highest priority and override external
start/stop control.
12
Max.
Q
Max.
Q

7.6 Temperature influence

The temperature influence function is available with
proportional- or constant-pressure control mode.
To be set with the R100, see section 8. Setting the
pump.
When the temperature influence function is
activated, the setpoint for head will be reduced
according to the liquid temperature.
The temperature influence limits can be set to 122 °F
(50 °C) or 176 °F (80 °C). The temperature limits are
not adjustable.
These temperature limits are called T
setpoint is reduced in relation to the head set
(= 100 %) according to the characteristics below.
H
100%
H
actual
30%
68 122
T
actual
Fig. 12 Temperature influence
In the above example, T
been selected. The actual liquid temperature T
causes the setpoint for head to be reduced from
100 % to H .
actual
The temperature influence function requires:
• Proportional- or constant-pressure control mode.
• The pump must be installed in the supply-side
pipe.
• System with supply-pipe temperature control.
Temperature influence is suitable in:
• systems with variable flows (e.g. two-pipe heating
systems), in which the activation of the
temperature influence function will ensure a
further reduction of the pump performance in
periods with small heating demands and
consequently a reduced supply-pipe temperature.
• systems with almost constant flows (e.g. one-pipe
heating systems and radiant floor heating
systems), in which variable heating demands
cannot be registered as changes in the head as is
the case with two-pipe heating systems. In such
systems, the pump performance can only be
adjusted by activating the temperature influence
function.
Selection of T
max.
In systems with a dimensioned supply-pipe
temperature of:
• up to and including 131 °F (55 °C), select T
122 °F (50 °C),
• above 131 °F (55 °C), select T
(80 °C).
. The
max.
H
175
T F
= 176 °F (80 °C) has
max.
actual
max.
= 176 °F
max.
Q
=