14.3.4 Connection options for the PCB (SCU-X03)
The SCU-X03 PCB can control a modulating central heating pump. De
pending on the make and type of pump, the pump can be controlled by a
0–10 V, 4–20 mA or a PWM signal. The speed of the pump is modulated
based on the signal received from the boiler.
Note
For correct connection of the pump, see the documentation sup
plied with the pump.
Connecting on/off contact
1. Connect the on/off contact of the CH pump to the connector X1.
Caution
Do not use the on/off contact to interrupt the power supply to the
pump.
Connecting a central heating pump
1. Connect the CH pump controller to the connector X2.
Select the type of signal that will be received from the boiler using the rota
ry knob SW1 on the PCB. See table below
No.
Description
0
Pump modulation signal
1
Required heat output of boiler
2
Current heat output of boiler
3
–
4
–
5
–
6
–
7
–
8
–
9
–
Caution
If possible, use the pump modulation signal. This provides the
most accurate pump control.
In positions 3 to 9 the control PCB receives no signal from the
boiler and the boiler responds as in position 0.
If the automatic burner unit does not support pump modulation,
the pump will behave as an on/off pump.
Select the type of signal that controls the pump using the rotary knob SW2
on the PCB. See table below.
No.
Description
0
0–10 V (Wilo pump)
1
0–10 V (Grundfoss pump)
2
PWM
3
4–20 mA
4
–
5
–
6
–
7
–
8
–
9
–
Fig.75 SCU-X03 PCB
AD-0000061-01
X4
X3
SCU-X03
X2
SW2
SW1
X1
Ctrl
0 +
0 +
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