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icos - Installation & Servicing
FAULT FINDING
FAULT FINDING FAULT FINDING FAULT FINDING FAULT FINDING FAULT FINDING
70
L.....F....... (FLAME ERROR)
Check the ignition electrode and associated harness for:
continuity, visual condition, position
(Refer to Frame 56).
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 57).
Replace as necessary.
If the boiler reset button is
pressed does the boiler ignite for
a short time then extinguish?
Is 200V DC supply available
at the gas valve ?
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
71
L.....E...... or H.....E...... (BOARD ERROR)
Internal fault within the PCB
Replace PCB
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 indicates that the correct voltage is supplied to the gas valve. As an alternative to a multimeter a
mains 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 58. Are these functioning
correctly?
Replace
spark generator
YES
NO
Press and hold reset button for 2
seconds. Does boiler operate
correctly?
Turn boiler off and wait for 5
seconds.Turn boiler on.
Does boiler operate correctly?
NO
NO
YES
OK
YES
OK
Check syphon
and condensate
drain pipework
for blockage
Check for an excess voltage between neutral
and earth. Is the value below 50V?
LE ONLY: Check continuity of OH thermostat.
Is this correct?
HE ONLY: Check earth wire is connected to
detection lead. Is this correct?
Check all earths for continuity
YES
YES
YES
YES
Check earth connection to the boiler. If value is still in
excess of 50V consult a Qualified Electrician to check the
household electrical supply and circuitry
Correct wiring or replace thermostat
Correct wiring or replace detection lead
Correct connections
NO
NO
NO
NO