14.0 Fault Finding
44
Is
230V S/L-N & L-E
at mains input
terminal block ?
The polarity of the
mains input to the
boiler is reversed. This
must be rectified.
Is there
at least 18.1 mbar
dynamic at gas
valve inlet ?
Incorrect gas
supply to boiler.
Reset lockout.
Does fan run ?
Is
control PCB fan
connection 24 Vac
across
(L)
?
Replace control PCB.
Is
there no spark
and no gas ?
(check at meter)
Is there
230V at control
PCB connection to
ignition PCB
(M)
?
Is
there gas but no
spark ?
Is
spark probe
damaged ?
Replace spark probe.
Is
there spark but no
gas ?
Is
there 230V
at ignition PCB
connection to gas
valve
(O)
?
Replace ignition PCB.
Replace control PCB.
Is
the detection
probe damaged ?
Is
wiring from ignition
PCB to detection
probe OK ?
Rectify wiring.
Replace detection probe.
Ignition Lockout
NO
YES
NO
Is
condensate trap
blocked ?
Clear blockage and
dry sensors
YES
NO
NO
NO
YES
YES
YES
YES
YES
NO
YES
YES
NO
NO
NO
NO
NO
YES
YES
YES
YES
NO
NO