Morco GB24 - L6: False Flame Lockout; F1: Low Water Pressure; F2;Fn;Ln: Flame Loss

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SECTION 8 - FAULT CODES
8.4 ‘L6’ - FALSE FLAME LOCKOUT
8.5 ‘F1’ - LOW WATER PRESSURE
8.6 ‘F2 OR Fn OR Ln’ - FLAME LOSS
Does the boiler ignite for a short
time and then extinguish?
YES
YES
Is the Gas Pressure available at the
Boiler Inlet (35 mbar ±5.0mbar)?
Check the ignition/detection
electrode and associated harness
for: continuity, visual condition and
position. Check if condensate pipe
is blocked. Check if ue is blocked.
Replace as necessary.
Is the top ue manifold seal present
and correctly tted. ?
NO
NO
Check gas supply and
rectify fault
NO
YES
Is 24Vdc supply available at the
Gas Valve while the ame is on?
YES
Check spark generator and
associated harness for: continuity
and visual condition. Are these
functioning correctly?
YES
Check the ignition/detection
electrode and associated harness
for: continuity, visual condition and
position. Are these functioning
correctly?
YES
Check siphon and condensate
drain pipe work for blockage and
rectify if necessary. Boiler now
working OK?
Check wiring from gas
valve to PCB for continuity.
If the wiring is OK then
replace the PCB
NO
Replace Spark Generator
and Harness as necessary.
NO
Replace Ignition/
Detection Electrode and
associated harness as
necessary
NO
Replace Gas Valve
Re-t correctly or replace
NO
Are the Boiler and CH System lled with anti-freeze/inhibitor solution
and all isolation and radiator valves open (check pressure gauge is
between 1 to 1.5 bar)?
NO
NO
YES
Fill and vent the system and open all
isolation valves
YES
Are connections on water pressure sensor secure?
Re-t connections
Replace water pressure switch
Restart the boiler. Does the boiler
work OK?
NO
NO
Replace Spark Generator.
If problem persists
replace PCB.
Remove ame detection plug from spark generator. Is
there continuity between plug and PCB?
Replace harness
YES
RESTART PROCEDURE - To restart boiler, press and
release the restart button.
YES
No further action required.