Worcester 24ijunior

39
Remove combustion
chamber cover.
Is the sense electrode
and lead in good
condition and is gap
correct?
Replace flame sensor
or wiring.
No
No
Remove multiway
connector from board
position ST16.
Is there continuity
from pin 10 (white
wire) to flame sensor?
Yes
Yes
Yes
Relace control board.
NOTE: It is not
possible to reliably
check the cross-light
performance of the
burner, or the
efficiency of the
gas/water heat
exchanger.
If there is still a
problem, investigate
flue problems or
replace burner or
injector or heat
exchanger.
Check the flashing
fault signal occur at
the start of a demand.
Check flashing occurs
at the end of a
demand.
Gas valve leak is
detected.
No
Yes
Check flashing occurs during
a demand.
Pump could be partially
blocked.
Clean pump & flush system.
Re-fix sensor to pipe.
No
Turn off boiler. Remove
inner casing cover and
check position of
primary sensor (on
heat exchanger in
front of overheat
thermostat).
Is it correctly fixed to
pipe?
Yes