34
Yes
Are the spark
electrodes and gap
connections in
good order?
No
Repair or replace
electrodes or leads.
Yes
Replace control board.
(Section 15.4.9)
Does the burner
ignite? (use spy glass
to observe flame)
No
(LOCKOUT will occur
after 8 seconds)
Is gas supply
connected and at
the correct pressure?
No
Repair or replace
flame sensor or
wiring.
Rectify gas supply
problem.
Yes
Yes
Yes
Press facia button to
reset the LOCKOUT.
With a new boiler
demand is there
approx 210V DC
across pins 1& 4 of
connector X3 during
spark sequence?
Replace control board.
(Section 15.4.9)
No
Yes
Replace the gas valve
(Section 15.4.1)
Does the flame
continue for more
than 10 seconds?
NOTE: Reverse
live/neutral polarity
will cause this fault.
And system should
be cool.
No
Switch off mains
supply. Remove boiler
front panel and
combustion chamber
cover. Is the sense
electrode and lead in
good condition and is
gap correct?
No
Yes
Extract control
board from facia. Is
there continuity
from flame sense
electrode to board
connector?
Yes
No
Replace control board.
(Section 15.4.9)
Check the burner
ports are clear and
clean the burner if
necessary.