14.0 Fault Finding
40
Is
control knob
on ?
Switch on
Is
wiring from control
PCB to interface PCB
OK
(F)
?
Does boiler
produce heat ?
Rectify wiring.
Replace control PCB.
Replace interface PCB.
NO
NO
NO
YES
YES
YES
Mains LED Flashing
Spark
Electrode
Ignition
PCB
Control
PCB
Condensate
Trap
Detection Electrode
Gas
Valve
Mains
Input
Optional
Pump Feed
Transformer
Overheat
Stat
Casing
Stat
Thermistor
Dry Fire
Flow Switch
DC
Fan
User PCB
br
br
w
g/y
g/y
br
b
b
b
b bk
br
bk
bk
bk
bk
bk
r
r
r
br
g
w
N P/F
bk
S/L
Pump
L
N
br
b
o o o o o o o o
g/y
br
r
b
bk
Earth
Electrode
F