Hach QC8500 Series 2, Руководство пользователя

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Troubleshooting
6.4.3 Valve artifact
This problem manifests itself when the valve is not operating properly. The symptom is
noise that occurs before each analyte peak. A valve artifact can be mistaken for a
refractive index. Valve artifacts are more noticeable when one or more reagents are
colored (
Figure 57 on page 68 ).
• To make sure the problem is caused by the valve, switch to another channel.
• For systems with only one channel:
a. Place the sample probe (or sample line) in the carrier solution or place some of
the carrier solution into a sample tube.
b. Run 3 or 4 injections using the carrier as the sample. If the problem is still present,
the injection valve is probably at fault.
• Make sure that the sample loop is not the cause of the problem.
• Check for flow restrictions in the manifold.
• Verify if the waste line in not submerged in the waste and is flowing freely.
• Call the manufacturer to get a loaner injection valve to troubleshoot this problem.
6.4.4 Carryover
Carryover can be recognized when two adjacent peaks merge into each other without
resolving to baseline. Carryover is normal when overrange samples are very high in
concentration. Run three injections of the high standard to determine if a carryover
problem is present. If the problem only occurs when samples are run, change to a
different method that can handle the concentrations of the samples.
Figure 57 Valve artifact