Selection Of Control Mode - Grundfos MAGNA1 Series Installation And Operating Instructions Manual

9. Selection of control mode

System application
In systems with relatively large pressure losses in the distribution pipes and in air-conditioning and cooling
systems.
• Two-pipe heating systems with thermostatic valves and
– very long distribution pipes
– strongly throttled pipe balancing valves
– differential-pressure regulators
– large pressure losses in those parts of the system through which the total quantity of water flows
(for example boiler, heat exchanger and distribution pipe up to the first branching).
• Primary circuit pumps in systems with large pressure losses in the primary circuit.
• Air-conditioning systems with
– heat exchangers (fan coils)
– cooling ceilings
– cooling surfaces.
In systems with relatively small pressure losses in the distribution pipes.
• Two-pipe heating systems with thermostatic valves and
– dimensioned for natural circulation
– small pressure losses in those parts of the system through which the total quantity of water flows
(for example boiler, heat exchanger and distribution pipe up to the first branching) or
– modified to a high differential temperature between flow pipe and return pipe
(for example district heating).
• Underfloor heating systems with thermostatic valves.
• One-pipe heating systems with thermostatic valves or pipe balancing valves.
• Primary circuit pumps in systems with small pressure losses in the primary circuit.
The pump can also be set to operate according to the max. or min. curve, like an uncontrolled pump:
• The max. curve mode can be used in periods in which a maximum flow is required. This operating
mode is for instance suitable for hot-water priority.
• 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 setback.
Select this control mode
Proportional pressure
H
Q
Constant pressure
H
Q
Constant curve
H
Q
21