IDEAL Logic HEAT 12, Installation And Servicing

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Fault Finding
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Ideal Logic Heat -
Installation and Servicing
70 aLTERNaTINg ‘F’ aND ‘2’ - FLaME LOss
Does the boiler ignite for a short
time and then extinguish?
yES
Is the Gas Pressure available at
the Boiler Inlet (>18 mbar)?
Check the detection electrode and
associated harness for: continuity,
visual condition and position (Refer
to Frame 57). Check if condensate
pipe is blocked. Check if flue is
blocked.
Replace as necessary
NO
Check gas supply and
rectify fault
NO
yES
Is 215Vdc supply available at the
Gas Valve while the flame is on?
(* See note)
yES
Check spark generator and associated
harness for: continuity and visual
condition. (Refer to Frame 58) Are
these functioning correctly?
yES
Check ignition electrode and
associated harness for: continuity,
visual condition and position.
(Refer to Frame 56) 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
Electrode and
associated harness as
necessary
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.
71 aLTERNaTINg ‘F’ aND ‘3’ - FaN FaULT
Does the wiring from the Fan to the PCB have secure connections at both ends
and has not deteriorated? Does the wiring have continuity?
yES
Rectify Wiring &
connections
Is there 230Vac at the Blue and Brown connections to the 3 way connection on
the Fan?
NO
Replace PCB
Replace Fan
NO
yES
NO
72 aLTERNaTINg ‘F’ aND ‘4’ - FLOW ThERMIsTOR FaULT
Remove the Flow Thermistor from the CH Flow Pipe
and disconnect the wires.
Check the resistance using a suitable multimeter
connected across the thermistor’s terminal pins.
At 25 o C expect 9,700 - 10,300 Ohms
At 60 o C expect 2,400 - 2,600 Ohms
At 85
o
C expect 1,000 - 1,100 Ohms
Is the Thermistor value correct?
Is there continuity between the PCB and the Thermistor?
yES
Replace PCB
Fit a new Thermistor
NO
Check and replace wiring
as necessary
yES
NO
73 aLTERNaTINg ‘F’ aND ‘5’ - RETURN ThERMIsTOR FaULT
Remove the Return Thermistor from the CH Return
Pipe and disconnect the wires.
Check the resistance using a suitable multimeter
connected across the thermistor’s terminal pins.
At 25 o C expect 9,700 - 10,300 Ohms
At 60 o C expect 2,400 - 2,600 Ohms
At 85
o
C expect 1,000 - 1,100 Ohms
Is the Thermistor value correct?
Fit a new Thermistor
NO
Is there continuity between the PCB and the Thermistor?
yES
Replace PCB
Check and replace wiring
as necessary
yES
NO