Selection Of Control Mode - Grundfos MAGNA3 65-XX Notice D'installation Et De Fonctionnement

15. Selection of control mode

System application
Recommended for most heating systems, especially in systems with relatively large pressure losses in the
distribution pipes. See description under proportional pressure.
In replacement situations where the proportional-pressure duty point is unknown.
The duty point has to be within the AUTO
makes the necessary adjustment to the actual system characteristic.
This setting ensures minimum energy consumption and noise level from valves, which reduces operating costs
and increases comfort.
The FLOW control mode is a combination of AUTO
ADAPT
This control mode is suitable for systems where a maximum flow limit, FLOW
continuously monitors and adjusts the flow, thus ensuring that the selected FLOW
Main pumps in boiler applications where a steady flow through the boiler is required. No extra energy is used for
pumping too much liquid into the system.
In systems with mixing loops, the control mode can be used to control the flow in each loop.
Benefits:
• Enough water for all loops at peak load conditions if each loop has been set to the right maximum flow.
• The dimensioned flow for each zone (required heat energy) is determined by the flow from the pump.
This value can be set precisely in the FLOW
• When the flow is set lower than the balancing valve setting, the pump will ramp down instead of losing energy
by pumping against a balancing valve.
• Cooling surfaces in air-conditioning systems can operate at high pressure and low flow.
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
– a dimensioned pump head higher than 13 ft (4 meters)
– 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
– a dimensioned pump head lower than 6.5 ft (2 meters)
– 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.
operating range. During operation, the pump automatically
ADAPT
and FLOW
ADAPT
control mode without the use of pump throttling valves.
ADAPT
.
LIMIT
, is desired. The pump
LIMIT
is not exceeded.
LIMIT
Select this control
mode
AUTO
ADAPT
H
Q
FLOW
ADAPT
H
Q
Proportional
pressure
H
H
set
H
set
2
Q
Constant pressure
H
Q
37