In case of failure of this capacitor, most probably the fuses blow.
3.6.2 Additional reasons for excessive analysis duration
– Dirty dust trap, see Operation Manual chapter “Cleaning the dust trap”
– Saturated chemicals, see Operation Manual “Filling the reagent tubes”
– Cotton, glass or quartz wool is pressed too tight.
– The oxygen is not pure, or the catalyst furnace is faulty or cold, or the copper oxide is
depleted, see Operation Manual “Filling the reagent tubes”
– The temperature of the infrared cell is not yet stable. Either it is not switched on for at
least 1 hour, or the oxygen flow has not yet been running for 10 to 15 minutes ( power
switch on setting 2 ), see Operation Manual “Main power connections” and “Work
breaks”
– The thermostatic control of the infrared cell is defective, see “IR thermostatic control “
– Excessive combustion temperature, resulting in high blanks from the crucible (CO2).
3.6.3 One of the IR-sources is unstable
– Small resistance changes of one or more IR-sources can cause the
current to vary, thus affecting the intensity of the IR-radiation.
This problem will affect all the channels, due to the fact that the IR-sources are all
connected in series.
In order to find out whether this problem is present or not, an analysis cycle should be run
without a sample or a crucible. The baseline of the IR-cells can then be monitored on the
PC screen. See “Software helps”
The baselines should be quite stable. The drift within the usual time of analysis should be
in the range of 2 to 5mv, depending on the path lengths.
Remark Drift is the average of the noise.
Due to the fact that the IR sources are connected in series, if one of them is damaged, a
typical effect is that all base lines drift simultaneously in the same direction, with
occasionally changing slope from positive to negative. However the same effect appears
in case of faulty power supply when the IR source voltage drifts up and down. This is
however less likely.
It is difficult, in case of such problem, to find which IR-source is faulty and it is therefore
easier to replace them all.
– A window of an IR-path is not gastight. The measuring gases pass through the leakage,
either into the chopper housing or to the IR-detector. In this case the typical effect is that
the base line does not come down to the initial starting level at the end of analysis, but it
remains at a constant level over the base line.
Perform a leakage test of the IR-paths. Replace the faulty IR-path. See chapter “IR path
cleaning and replacing”
– The infrared power supply is defective, so that the voltage stabilisation does not function.
– The Infrared electronics are faulty. See chapter “Infrared electronics”
3.6.4 The power voltage sinks below 180 VAC
– Even a momentary drop in the voltage is enough to cause problems.
Use a voltage stabilizer.
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