Vaillant ecoTEC plus 831 - Page 27

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27Instructions for installation and servicing ecoTEC
X 2
BUS
— +
24V
7 8 9
230V
L N 3 4 5
X 20
X40
X31
X12
X41
Electronic control box
Aqua sensor
ecoTEC plus only:
NTC
Hot water
outlet
Fan unit
Ignition electrode
NTC
flow
Diverter valve
Gas valve assembly
Water pressure sensor
NTC
return
X 20/5 red
X 20/7 black
X 20/7 black
X 20/8 blue
X 2/12 green
X 2/11 red
X 2/9 black
Pump
X 20/18 red (24 VDC)
X 20/9 blue (earth)
X 20/16 blue (earth)
X 20/13 black
X 20/12 black
X 20/4 grey (PWM)
X 20/3 black (Hall signal)
X 20/17 red (24 VDC)
X 2/15 brown C
X 2/8 blue D
X 2/16 black A
X 2/7 pink B
X 2/3 red (+ 5V)
X 2/2 black (earth)
X 2/6 green (signal)
X 2/5 violet (signal)
X 2/1 black
NTC
Plate heat
exchanger
X 2/4 orange
X 2/10 black
Thermal fuse
Plug
in
coupling
Fig. 4.16 Connection wiring ecoTEC combination boiler
Boiler installation sequence 4