Vaillant ecoTEC plus 612 Instructions For Installation And Servicing page 26

4 Boiler installation sequence
NTC
flow
X 20/5 red
X 20/7 black
X 20/8 blue
X 20/7 black
Gas valve assembly
X 2/9 black
X 2/11 red
X 2/12 green
X 2/3 red (+ 5V)
X 2/2 black (earth)
X 2/6 green (signal)
X40
X 20
Electronic control box
Fig. 4.16 Connection wiring ecoTEC combination boiler
26
NTC
Ignition electrode
return
Thermal fuse
X 20/18 red (24 VDC)
X 20/9 blue (earth)
Water pressure sensor
Aqua sensor
X41
X 2
X 20/13 black
X 20/12 black
Fan unit
X 20/16 blue (earth)
X 20/4 grey (PWM)
X 20/3 black (Hall signal)
X 20/17 red (24 VDC)
X 2/16 black A
X 2/7 pink B
X 2/15 brown C
X 2/8 blue D
X 2/4 orange
X 2/10 black
X 2/5 violet (signal)
X 2/1 black
— + 7 8 9 L N 3
BUS 24V 230V
Instructions for installation and servicing ecoTEC / 839592_09
Plug
in
coupling
Diverter valve
NTC
Plate heat
exchanger
ecoTEC plus only:
NTC
Hot water
outlet
4 5
Pump