Bosch Worcester 14/19CBI Installation And Servicing Instructions page 11

Fig.10. Boiler wiring diagram
Air pressure
switch
NC
NO
COM
Overheat
Thermostat
orange
*
black
Temperature
sensor
*
earth
Installer
Connections
Switched Live (Boiler Demand)
white
grey
brown
Gas Valve
Pump Live
Pump Neutral
Permanent Neutral
Permanent Live
Fan
*
Spark
Electrode
X4
X3
1
blue
X2
brown
X1
11
*
Polarity of these connections is not
important.
Flame
Sense
Electrode
1 1
X6
X5
Control Board
User control
potentiometer/switch
3 pin header
X7