45
14.0 Fault Finding
Replace fan.
Is
fan connection
24Vac across
(L)
?
Wiring from control
PCB to fan faulty.
Is ignition PCB
fuse OK ?
Replace
ignition
PCB.
Replace
ignition
PCB.
Is there
230V at ignition
PCB connection to
control PCB
(N)
?
Wiring from control
PCB to ignition
PCB faulty.
Check for short circuits
on ignition PCB and gas
valve. If OK replace fuse.
Is
wiring from
ignition PCB to
spark probe OK ?
Is
spark gap
between 3 and 5mm ?
Set spark gap to 4mm.
Rectify wiring.
Is
sensing tube
blocked ?
Unblock
Tube.
Is
there 230Vdc at the
end of the gas valve
lead ?
Replace gas valve lead.
Replace gas valve.
Replace
control
PCB.
Is
there 230V
ignition PCB burner on
pin to control PCB
(P)
?
Replace ignition PCB.
Burner On wiring from ignition
PCB to control PCB faulty.
Is
there 230V
control PCB burner on
pin to ignition
PCB
(Q)
?
NO
YES
YES
NO
NO
YES
YES
NO
NO
NO
NO
YES
YES
YES
YES
NO
NO
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
L
M
Q
N
P
O