PPM–400ST Formaldehyde Meter Operation Manual
7 TROUBLESHOOTING
Display Flashes
----
and the
Instrument Will Not
Sample
The three main reasons for this problem are:
1. The instrument has been accidentally calibrated
when no Calibration Standard was present.
2. The Calibration Standard used for calibration has
expired.
3. The instrument has been damaged and will need to
be repaired.
To determine which of these reasons applies
carefully follow the procedures shown below.
Please note that quoted results and values are for
tests performed at 25°C, if in doubt contact the
manufacturer.
1. Make sure that the instrument has been turned off
for about 5-minutes.
2. Hold down the
>
button whilst turning the
instrument on. The display will show
tESt
. Release
all the buttons.
3. A four-digit value will appear:
0.123
. Give the
instrument a few seconds to stabilise.
4. Note the initial value and an approximate rate of
change over a minute.
If the initial value or the rate of change was in excess
of
0.300
then it is likely that your sensor has been
damaged – contact PPM Technology or your dealer
for further details, otherwise continue with the
instrument still in the
tESt
mode:
1. With the sample nozzle inserted into a valid
Calibration Standard press the
$
button to take a
sample (see Section 4.3).
2. The display should show
0.000
as the pump starts
to run and rise up to a maximum as the sample is
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