54
icos system - Installation and Servicing
FAULT FINDING FAULT FINDING FAULT FINDING FAULT FINDING
FAULT FINDING
79
L.....F.... (FLAME DETECTION ERROR)
Check the ignition electrode and associated harness
for: continuity, visual condition, position
(Refer to Frame 61).
Are these functioning correctly ?
Check gas valve
wiring for
continuity
YES
Check the detection electrode and
associated harness for:
continuity, visual condition, position
(Refer to Frame 62).
Replace as necessary.
If the boiler reset button is
pressed does the boiler ignite for
a short time then extinguish?
Is 200 V DC supply
available at the gas valve ?
(see note).
NO
YES
YES
Is gas pressure available at
the boiler inlet ?
Replace PCB
Check gas supply
and rectify fault
Replace ignition electrode and associated
harness as necessary
NO
Replace gas valve
YES
NO
NO
Note. Due to the wave form of the rectified voltage, the reading will vary depending on the type of meter used to
measure the value (some may measure the possible peak voltage of 339V). In general terms a reading
greater than 150V indicate that the correct voltage is supplied to the gas valve. As an alternative to a
multimeter, a mains voltage checking device may be used. E.g. an electrical screwdriver or a mains tester.
Check spark generator and associated
harness for continuity and visual condition.
(Refer to Frame 63).
Are these functioning correctly ?
Replace spark
generator
NO
YES
Check syphon
and condensate
drain pipework
for blockage
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