41
4000121771-2
18 Fault Finding
FAULT: THE BURNER DOES NOT LIGHT AT ALL, BUT THERE IS AN IGNITION SPARK.
NO
NO
YES
YES
Are the gas taps on?
Test the gas control valve.
Turn on the gas taps.
Check the wiring.
If the problem persists, change the
control board (PCB).
Is there 24Vdc at the gas control valve?
for testing see component testing data.
Check resistance of safety valve coil.
11799
FAULT: THE ROOM TEMPERATURE IS INADEQUATE AND RADIATORS ARE LUKE-WARM.
YES
NO
Is the heating temperature on the boiler
set high enough?
Turn up settings
YES
Is the heating power adequate?
- Check the adjustment of the by-pass internal and
external (If fitted).
-
Check the 3-way valve is not passing into the
domestic hot water heat exchanger.
Is the room thermostat and or radiator
set high enough and calling for duty?
11899p
FAULT: THE BURNER LIGHTS, THEN GOES OUT.
CHECK
THE
PROBE
CHECK
THE MAINS
FAULT NOT FOUND
The flame is spreading across the
whole burner, but not being detected.
With the power turned off, check the
continuity between the spark electrode
and terminal H24 on the control board
(PCB). Check the connector on the end
of the wire.
Check that the spark electrode is
pointing towards the flame.
Check the spark electrode. Change it.
If the problem persists, change the
control board (PCB).
(flame detection module faulty).
11798
