Worcester C1 Installation And Servicing Instructions page 36

No
Is the gas supply
connected and at the
correct pressure?
Yes
Remove front panel.
No
Reset and restart the
boiler. Can a flame be
seen through the spy
glass?
Yes
Turn off boiler. Remove
inner cover and
combustion chamber
cover. Are the sense
electrode and lead in
No
good condition and is
gap correct?
Yes
Remove multiway
connector from board
No
position ST16.
Is there continuity
from contact 11 (white
wire) to flame sensor?
Yes
No
Does the flashing fault
signal occur at the
start of a demand?
Yes
Replace control board (Section 15.4.10).
Note: It is not possible to reliably check
the cross-light performance of the burner.
In the unlikely event of such a fault,
investigate flue problems or replace
burner or injector. (Section 15.4.4).
Rectify gas supply
problem.
Remove inner cover.
No
Reset and restart the
boiler. Does a spark
occur across the
electrodes?
Yes
Turn off boiler. Remove
the multiway
connector from board
position ST16. Test
No
resistance across
contacts 7 and 8
(brown wires) and 9
and 10 (violet wires).
Are both reading
below 200 ohms?
Yes
Replace control board.
(Section 15.4.10).
If problem not solved
replace gas valve.
(Section 15.4.1)
Repair or replace flame
sensor
(Section 15.4.3)
or wiring.
Flashing occurs at end
of demand. Replace
gas valve.
(Section 15.4.1).
36
No
Are the electrodes and
gap and connections
in good order?
Yes
Replace control board.
(Section 15.4.10).
Remove both brown
connectors from gas
No
valve.
Is there continuity
from brown and violet
wires to multiway
connector?
Yes
Replace gas valve.
(Section 15.4.1).
Repair or replace
spark electrode
(Section 15.4.2)
or HT leads
Repair or replace
harness.