Description And Function; Description Of The Pump; Operation Of The Pump - Wilo Yonos MAXO-D Installation And Operating Instructions Manual

6 Description and function

6.1

Description of the pump

The Wilo-Yonos MAXO high-efficiency pumps are glandless pumps with a permanent
magnet rotor and an integrated differential pressure control. Single (fig. 1a) and double
pumps (fig. 1b) are available.
1 Control module
1.1 LED display
1.2 Fault signal LED
1.3 Operating knob
1.4 Connection plug
2 Pump housing
2.1 Direction-of-flow symbol
6.2

Operation of the pump

There is a control module (fig. 1a, item 1) in a vertical design on the motor housing, which
controls the differential pressure of the pump to a setpoint within the control range.
Depending on the control mode, the differential pressure follows different criteria. In all
control modes, however, the pump adapts itself continuously to the changing power
requirements of the unit, which is the case especially when thermostatic valves, zone
valves or mixers are used. In addition to differential pressure control, the pump can be set
to 3 fixed speed stages.
The main advantages of the electronic control are the following:
• Energy savings and while reducing the operating costs at the same time
• Reduction of flow noises
• Reduction of the number of differential pressure valves required.
The following settings can be made:
Nominal delivery head:
The LED display shows the setpoint set on the pump in meters (m). The setpoint can be
adjusted or changed by turning the operating knob.
Control mode:
Variable differential pressure (p-v):
The electronics change the differential pressure setpoint to be maintained by the pump
linearly between ½H
with the flow rate.
Constant differential pressure (p-c): The electronics keep the differential pressure cre-
ated by the pump constant above the permitted flow range at the selected differential
pressure setpoint H
3 speed stages (n = constant): The pump runs uncontrolled in one of three settable fixed
speed stages.
SSM: The contact of the collective fault signal (potential-free normally closed contact)
can be connected to a building automation system. The internal contact is closed if the
pump is without power, if there is no fault or if there is a malfunction of the control mod-
ule. The SSM behaviour is described in sections 10.1 and 10.2.
In the event of a malfunction (depending on the error code, see chapter 10.1), the fault
signal LED is continuously illuminated in red (fig. 1a, item 1.2).
Installation and operating instructions Wilo-Yonos MAXO/-D
and H . The differential pressure setpoint H decreases or increases
S S
up to the maximum pump curve.
S
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