L1' - Flow Temp Overheat Lockout; L2' - Ignition Lockout - Zanussi ULTRA+ COMBI 30 Installation And Servicing

4.2 'L1' - FLOW TEMPERATURE OVERHEAT LOCKOUT
Is the Boiler and CH System filled with water and all
isolation and radiator valves open?
Is the Flow/Return Differential across the Boiler in
excess of 30°C?
Check the Return Thermistors
(Refer to Section 3.12)
Check resistance using a suitable multimeter
connected across the thermistor's terminal pins
At 25 C expect 9,700 - 10,300
o
At 60 C expect 2,400 - 2,600
o
At 85 C expect 1,000 - 1,100
o

4.3 'L2' - IGNITION LOCKOUT

If the boiler is restarted does the
boiler ignite for a short time and
then extinguish?
YES
Check the detection electrode
and associated harness for:
continuity, visual condition and
position (Refer to Section 3.14).
Check if the condensate pipe is
blocked.
Check flue is installed correctly.
Replace as necessary.
Check siphon and condensate
drain pipework for blockage and
rectify if necessary. Boiler now
working OK?
NO
Replace Gas Valve
RESTART PROCEDURE: to restart boiler press the restart button.
56
SECTION 4 - FAULT FINDING
YES
NO
Ohms
Ohms
Ohms
NO
Is the Gas Pressure available at
the Boiler Inlet (>18 mbar)?
Is 24Vdc supply available at the
Gas Valve?
Unplug gas valve.
Is resistance between outside pins
between 4k Ω (± 2)?
Check spark generator and
associated harness for: continuity
and visual condition. (Refer
to Section 3.15) Are these
functioning correctly?
Check ignition electrode and
YES
associated harness for: continuity,
visual condition and position.
(Refer to Section 3.13) Are these
functioning correctly?
NO
Fill and vent the system and open all
isolation valves, then restart boiler
YES
Check that the Pump is rotating freely. Is
the Differential now below 20°C?
NO
Replace the Pump,
then restart boiler
RESTART PROCEDURE: to restart boiler press the restart
button.
YES
YES
YES
YES
YES
OK, now
restart boiler
NO
Check gas supply and
rectify fault
Check wiring connection
NO
from gas valve to PCB for
continuity. If the wiring is
OK then replace the PCB
NO
Replace Gas Valve
NO
Replace Spark
Generator and harness
as necessary
Replace Ignition
NO
Electrode and
associated harness as
necessary
Installation and Servicing