Overheat/Ignition Lockout - IDEAL LOGIC + Combi 24 Installation And Servicing

74 OVERhEAT LOCKOUT - 1 FILL sysTEM TO 1.0 BAR - 2 BLEED RADIATORs -
3 ChECK RADIATOR VALVEs OpEN -
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 Flow and Return Thermistors
(Refer to Frame 69)
Check resistance using a suitable multimeter
connected across the thermistor's terminal pins
At 25 C expect
o
At 60 C expect
o
At 85 C expect
o
REsET pROCEDURE - To reset boiler, turn mode knob to reset position and immediately turn knob back to required setting.
75 IgNITION LOCKOUT - 1 ChECK OThER gAs AppLIANCEs WORK -
2 REsET BOILER - 3 CONTACT INsTALLER
If the boiler is reset 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 Frame 51).
Check if the condensate pipe is
blocked.
Replace as necessary
Check siphon and condensate
drain pipe work for blockage and
rectify if necessary. Boiler now
working OK?
NO
Replace Gas Valve
* 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. In general terms a reading greater than 150V indicates that the correct voltage is supplied to the gas valve.
REsET pROCEDURE - To reset boiler, turn mode knob to reset position and immediately turn knob back to required setting.
+
Ideal Logic Combi -
Fault Finding
YES
NO
9,700 - 10,300 Ohms
2,400 - 2,600 Ohms
1,000 - 1,100 Ohms
NO
Is the Gas Pressure available at
the Boiler Inlet (>18 mbar)?
Is approx 215Vdc supply available
at the Gas Valve? (* See note)
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
Frame 52) Are these functioning
correctly?
YES
Check ignition electrode and
associated harness for: continuity,
visual condition and position.
(Refer to Frame 50) Are these
functioning correctly?
Installation and Servicing
4 REsET BOILER - 5 CONTACT INsTALLER
NO
Fill and vent the system and open all
isolation valves, then reset boiler
Check that the Pump is rotating freely. Is
YES
the Differential now below 20°C?
NO
Replace the Pump,
then reset boiler
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
OK, now
reset boiler
Check gas supply and
rectify fault
Check wiring connection
from gas valve to PCB for
continuity. If the wiring is
OK then replace the PCB
Replace Gas Valve
Replace Spark
Generator and harness
as necessary
Replace Ignition
Electrode and
associated harness as
necessary
55