Vaillant ecoTEC plus 831 - Page 28

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28 Instructions 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
Fan unit
Ignition electrode
NTC
flow
Gas valve assembly
Hot water
contact C1/C2
Water pressure sensor
NTC
return
X 20/5 red
X 20/7 black
X 20/7 black
X 20/8 blue
X 2/10 black
X 2/14 brown
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)
tank NTC
connection
X 2/4 orange
X 2/10 black
Thermal fuse
Plug
in
coupling
Fig. 4.17 Connection wiring ecoTEC system boiler
4 Boiler installation sequence