Ideal Heating LOGIC+ SYSTEM S18, Installation & Servicing

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Installation and Servicing
SECTION 4 - FAULT FINDING
4.2 ‘L1’ - FLOW TEMPERATURE OVERHEAT LOCKOUT OR NO WATER FLOW LOCKOUT
Is the Boiler and CH System filled with water and all
isolation and radiator valves open?
YES
Fill and vent the system and open all
isolation valves, then restart boiler
Is the Flow/Return Differential across the Boiler in
excess of 30°C?
NO
Check that the Pump is rotating freely. Is
the Differential now below 20°C?
YES
NO
Check the Control/No Water Flow and Return
Thermistors (Refer to Sections 3.13 & 3.16)
Replace the Pump,
then restart boiler
NO
OK, now
restart boiler
YES
4.3 ‘L2’ - IGNITION LOCKOUT
If the boiler is restarted does the
boiler ignite for a short time and
then extinguish?
YES
Is the Gas Pressure available at
the Boiler Inlet?
Check the detection electrode
and associated harness for:
continuity, visual condition and
position (Refer to Section 3.15).
Check if the condensate pipe is
blocked.
Check flue is installed correctly.
Replace as necessary
NO
Check gas supply and
rectify fault
NO
YES
Is 24Vdc supply available at the
Gas Valve?
YES
Check spark generator and
associated harness for: continuity
and visual condition. (Refer
to Section 3.15) Are these
functioning correctly?
YES
Check ignition electrode and
associated harness for: continuity,
visual condition and position.
(Refer to Section 3.14) Are these
functioning correctly?
NO
Check siphon and condensate
drain pipe work for blockage and
rectify if necessary. Boiler now
working OK?
Check wiring connection
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
Electrode and
associated harness as
necessary
NO
Replace Gas Valve
YES
Unplug gas valve. Is resistance
between outside pins 4K Ω (±2)?
YES
Replace Gas Valve
NO
RESTART PROCEDURE - To restart boiler, press the RESTART button.
RESTART PROCEDURE - To restart boiler, press the “RESTART” button.
If the PCB has been replaced check a BCC has been
fitted then restart the boiler.