Differential Pressure Control Modes; General Functions Of The Pump - Wilo Yonos ECO BMS Notice De Montage Et De Mise En Service

6.2 Function of the pump
There is a control module (Fig. 1, item 5) in axial design on the motor housing, which con -
trols the differential pressure of the pump to a setpoint within the control range. Depend -
ing on the control mode, the differential pressure follows different criteria. In all control
modes, however, the pump adapts itself continuously to the changing power require -
ments of the unit, which is the case especially when thermostatic valves, zone valves or
mixers are used.
The basic advantages of the electronic control are:
• Energy savings and hence reduction of the operating costs,
• Reduction of flow noises,
• Reduction of the number of differential pressure valves required.
6.2.1 Settings
On the front of the control module is the "red button" (Fig. 1, item 4) as a central operating
element, which features three setting ranges.
The following settings can be made:
Variable differential pressure setting range (∆p-v):
Fig. 1, item 3: The control mode ∆p-v is active
Constant differential pressure setting range (∆p-c):
Fig. 1, item 2: The control mode ∆p-c is active
Setting range Ext. In:
Fig. 1, item 1: External speed adjustment by 0–10V analogue input.

6.2.2 Differential pressure control modes

Variable differential pressure (∆p-v):
The electronics change the differential pressure setpoint to be maintained by the pump
in linear form between ½Hs and Hs. The differential pressure setpoint Hs falls or increases
with the flow rate (Fig. 5), factory setting.
Constant differential pressure (∆p-c):
The electronics maintain the differential pressure created by the pump above the permit -
ted flow range constantly at the selected differential pressure setpoint Hs up to the max -
imum pump curve (Fig. 6).
6.2.3 Control signal 0–10V
The function linked to the 0-10V analogue control signal behaves as follows (Fig. 7):
U < 1 V:
2 V < U < 3 V:
1 V < U < 3 V:
3 V < U < 10 V: Speed varies between n

6.2.4 General functions of the pump

• The pump is equipped with an electronic overload protection function which switches off
the pump in the event of an overload.
Installation and operating instructions Wilo-Yonos ECO BMS
Pump stops
Pump runs at minimum speed (starting)
Pump runs at minimum speed (operation)
and n (linear)
min max
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