Selection Of Control Mode; Setpoint Setting - Grundfos MAGNA 40-120 Montage- Und Betriebsanleitung

7.2 Selection of control mode

System type Description
Grundfos recommends to let the pump remain in AUTO
Typical heating
This ensures optimum performance at the lowest possible energy
systems
consumption.
1. Two-pipe
heating
systems with
thermostatic
valves and:
Relatively great
head losses in
the distribution
pipes and air-
conditioning
systems
2. Primary circuit pumps in systems with great head losses in the primary
circuit.
3. Air-
conditioning
systems with
1. Two-pipe
heating
systems with
thermostatic
valves and:
Relatively small
head losses in
the distribution
pipes
2. Underfloor heating systems with thermostatic valves.
3. One-pipe heating systems with thermostatic valves or pipe balancing
valves.
4. Primary circuit pumps in systems with small head losses in the primary
circuit.

7.2.1 Setpoint setting

If AUTO is selected, the setpoint cannot be set.
ADAPT
The setpoint can be set by pressing
the pump is in control mode:
• proportional pressure
• constant pressure
• constant-curve duty.
Set the setpoint so that it matches the system.
A too high setting may result in noise in the system
whereas a too low setting may result in insufficient
heating or cooling in the system.
14
• with a dimensioned pump head higher than
4 metres,
• very long distribution pipes,
• strongly throttled pipe balancing valves,
• differential pressure regulators,
• great head losses in those parts of the system
through which the total quantity of water flows
(e.g. boiler, heat exchanger and distribution pipe up
to the first branching).
• heat exchangers (fan coils),
• cooling ceilings,
• cooling surfaces.
• with a dimensioned pump head lower than
2 metres,
• dimensioned for natural circulation,
• with small head losses in those parts of the system
through which the total quantity of water flows
(e.g. boiler, heat exchanger and distribution pipe up
to the first branching) or
• modified to a high differential temperature between
flow pipe and return pipe (e.g. district heating).
or when
Select this
control mode
mode.
ADAPT
AUTO
Proportional
pressure
Constant
pressure
ADAPT