Grundfos MAGNA3 D Installation And Operating Instructions Manual page 49

9.6.8 "Setpoint influence"
Navigation
"Home" > "Settings" > "Setpoint influence"
This menu offers the following options:
• External setpoint function
• Temperature influence.
"External setpoint function"
Navigation
"Home" > "Settings" > "Setpoint influence" > "External setpoint
function"
Setting
1. Select "Linear with Min." with
Note: The analog input must be set to "External setpoint
influence" before the "External setpoint function" can be enabled.
If the analog input is set to external setpoint influence, the
external setpoint function is automatically activated with "Linear
with Min.". See section 8.11.4 Analog input.
For detailed information on "External setpoint function", see
section 8.11.6 External setpoint function.
"Temperature influence"
Navigation
"Home" > "Settings" > "Setpoint influence" > "Temperature
influence"
This menu offers the following options:
• Not active
• Active, Tmax. = 120 °F
• Active, Tmax. = 170 °F.
Setting
1. Select "Temperature influence" with
2. Choose the desired maximum temperature with
press [OK].
When this function is enabled in proportional- or
constant-pressure control mode, the setpoint for head is reduced
according to the liquid temperature.
or and press [OK].
or and press [OK].
or and
You can set the temperature influence to function at liquid
temperatures below 176 or 122 °F (80 or 50 °C). These
temperature limits are called T
max.
relation to the head set which is equal to 100 %, according to the
characteristics below.
H
100 %
H
actual
30 %
68 122 176
20 50 80
T
Fig. 60 "Temperature influence"
In the above example, T , which is equal to 176 °F (80 °C),
max.
has been selected. The actual liquid temperature, T
the setpoint for head to be reduced from 100 % to H
Requirements
The temperature influence function requires the following:
• proportional-pressure, constant-pressure or constant-curve
control mode
• pump installed in flow pipe
• system with flow-pipe temperature control.
Temperature influence is suitable for the following systems:
• Systems with variable flows for example two-pipe heating
systems, in which the enabling of the temperature influence
function ensures a further reduction of the pump performance
in periods with small heating demands and consequently a
reduced flow-pipe temperature.
• Systems with almost constant flows, for example one-pipe
heating systems and underfloor 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, you can only adjust the pump performance by
enabling the temperature influence function.
Selection of maximum temperature
In systems with a dimensioned flow-pipe temperature:
• Up to and including 131 °F (55 °C), select a maximum
temperature equal to 122 °F (50 °C).
• Above 131 °F (55 °C), select a maximum temperature equal
to176 ° F (80 °C).
You cannot use the temperature influence function in
air-conditioning and cooling systems.
. The setpoint is reduced in
H
T [°F] Q
T [°C]
, causes
actual
.
actual
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