Vaillant ecoTEC plus 937 Instructions And Maintenance Instructions page 28

4 Sequence of operations during installation
Return temperature
Flow temperature
sensor (NTC)
sensor (NTC)
X 20/5 red
X 20/7 black
X 20/8 blue
X 20/7 black
Gas valve
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
Electronics box
Fig. 4.20 Wiring diagram combi boiler
28
Ignition electrode
Thermal fuse
X 20/18 red (24 VDC)
X 20/9 blue (Erde)
Water pressure sensor
X41
X 2
X 20/13 black
X 20/12 black
Fan
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 4
BUS 24V 230V
Installation and maintenance instructions ecoTEC plus 0020031552_03
Plug
connection
Diverter valve
Plate
heat exchanger
(NTC)
Hot water
outlet (NTC)
5
Pump