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6.13 Other common problems
Problem type
Flow related
Chemistry and/or Flow related
Chemistry and/or Flow related
Software and/or Hardware
related
Software and/or Hardware
related
Table 14 Troubleshooting problems
Problem description
The flow is moving
backwards.
Air bubbles are coming
out of the heater block,
but no air is getting into it.
A white precipitate is
formed inside the manifold
tubing when running TKN.
The diagrams and reports
show areas but no
concentrations for all
samples.
Sampler fails to initialize
to wash.
Solution
There is a blockage on the manifold. Refer to
page
73.
Degas all reagents with helium unless otherwise indicated in the
QuikChem method. A back-pressure loop may be used to keep
the air in solution. Refer to
instructions on making a back-pressure loop. If the problem only
occurs with samples, this might be due to the presence of
carbonates. Do a carbonate test on some samples by adding
few drops of 1 M HCl. If some foam or effervescence is visible,
treat the samples to eliminate the carbonates.
A puncture on the heated tubing wrapped on the heater mandrel
could introduce air bubbles. Turn the heater off and allow it
some time to cool. Run some standards to see if the air bubbles
persist. If this is the case, rewrap the heated coil using Teflon
tubing 0.032" ID.
Run a strong solution of sodium hydroxide through all the
manifold reagent lines to remove the precipitate. If the
precipitate is not removable, rewrap the entire manifold and
heater. This chemistry requires running buffer solution before
any of the other reagents.
Avoid any precipitate—Place all the reagent lines in deionized
water before running any reagents. Turn the pump on at speed
of 35. Run the water for one minute. Place the buffer line in the
buffer container. Run the buffer for a couple of minutes. Put the
rest of the reagents in line. When the chemistry run is complete,
remove the buffer line last and put in the deionized water rinse
container.
The buffer in the TKN method is very close to saturation. If some
crystals are formed in the bottom of the container, try remaking
the buffer by adding the reagents in the following order:
1
Dissolve the sodium phosphate dibasic heptahydrate in the
water.
2
Add the disodium EDTA and stir until dissolved. The
solution will be slightly turbid.
3
Add the sodium hydroxide and dissolve completely by
shaking or stirring.
The system has not been calibrated. The Calibration Results
show the calibration curves for the channels run.
Before attempting to troubleshoot this problem, make sure the
system has the latest version of software installed. This problem
could be caused by the sampler itself or a loose sampler cable.
Read
section 3.3 on page
21.
Troubleshooting
section 6.5 on
section 6.3.1 on page 64
for
79
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Table of Contents
Troubleshooting
