Brochure

Product range
MAGNA3
3
8
Pump selection
Frequently, pumps are selected based on a maximum
flow and pressure loss in a system as well as peak
efficiency of the pump. For circulators in variable
demand systems such as a heating system where the
heat load varies with the season and time of day it is
more optimal to select a pump for this varying demand
rather than one specific duty point.
The MAGNA3 has been optimized for variable demand
systems. For variable loads, when possible it is most
ideal to size and select the pump such that the
maximum flow and pressure required is on the right
hand side of the pump performance curve.
This enables the pump to have higher efficiency at
partial load and allows the pumps to slow down more
at these partial loads yielding significant energy
savings.
Pump size
The system characteristic is used together with the
pump’s performance curve for sizing and correct pump
selection.
The selection of pump size should be based on the
following:
• required maximum flow
• maximum pressure loss in the system.
Refer to the system characteristics to determine the
duty point. See fig. 5.
Fig. 5 System characteristic
Operating conditions
When selecting a pump, always verify the operating
conditions are fulfilled, Refer to “Operating conditions”
on page 22 for:
• liquid quality and temperature
• ambient conditions
• minimum inlet pressure
• maximum operating pressure.
Control modes
•AUTO
ADAPT
(factory setting): Is suitable for most
installations. Auto adapt is proportional pressure
control where the pump sets and adapts its own set
point based on maximum system conditions.
•FLOW
ADAPT
, FLOW
LIMIT
: in systems where a flow
limitation is required.
• Proportional-pressure control in systems with
considerable pressure loss variation in relation to
large flow variations; ie if more than 50 % of
pressure loss is due to friction loss in the pipe
system
• Constant-pressure control in systems with
insignificant pressure loss variation in relation to
large flow variations; ie if less than 50 % of pressure
loss is due to friction loss in the pipe system
• Constant-temperature control in heating systems
with a fixed system characteristic, for example
domestic hot-water systems.
• Constant-curve duty.
Communication
The Grundfos CIM modules (CIM = Communication
Interface Module) enable the MAGNA3 to connect to
standard fieldbus networks, offering substantial
benefits:
• complete process control and monitoring
• modular design, prepared for future requirements
• based on standard functional profiles
• simple configuration and easy installation
• open communication standards
• reading warning and alarm indications.
For further details, see section “CIM modules” on
page 30.
Fig. 6 Example of typical building management system
(BMS)
Note: A gateway is a device that facilitates the transfer
of data between two different networks based on
different communication protocols.
TM02 2040 3301
Q
Duty point
H
TM05 2710 1112