HACH LANGE QuikChem 8500 2 Serie Wartung Und Fehlerbehebung Seite 18

that the manifold agrees with the diagram in the QuikChem method. Look at the color of the
reagent pump tubes, the wavelength of the interference filter, the sample loop length, the heater
temperature if it is a heated chemistry, etc.
Standard
A
B
C
D
Troubleshooting based on peak shapes
For screen captures, detailed information and solutions, refer to the expanded user manual available
on the manufacturer's website.
Peak shape interpretation
Refractive index (Lachat uses this effect in
the methods for sea water and brackish
water.)
pH effect (such as a dip in the center of the
peaks)
Valve artifact (noise that occurs in the
baseline when the valve goes from load to
inject)
Carryover
Flat-topped peaks
No peaks
Noisy baseline
Drifting baseline
All negative peaks or all positive peaks
Identify injection valve faults
There are two main problems that can occur with the valve: clogs and hardware failure. To find out if
there are blockages in the injection valve, refer to
that the cables are connected correctly if the valve does not turn. A loose valve cable can also cause
problems. Make sure that the valve is connected correctly. If a motor or electronic failure occurs,
replace the valve or send the valve to the manufacturer for repair.
Find the flow blockages
1. If the pump makes an unusual noise, lift each tubing to see if air is aspirated. Examine the carrier
tubing to see if there are leaks. If yes, the carrier tubing is the suspect tubing.
2. Examine the nipple by the glass weight. Make sure that there is no blockage to the aperature.
18 English
Table 2 Example of dye standards
Universal dye (mL)
100
50
25
12.5
Overacidified samples; wrong carrier
Buffer solution with different pH; sampe pH, wrong pump tubes;
clogs or partial clogs; reagent preparation
Valve; sample loop; flow restrictions in manifold; waste tubing put in
water or does not flow freely
Wrong cycle period; wrong sample loop; wrong standard; rinse
station issue
Wrong standards; reagents; wrong sample loop; manifold;
overrange samples; wrong interference filter; dirty optics or other
detector issue
Valve timing settings; reagents; manifold setup; detector; pump
power set to off
Pump tubes; blockages; injection valve; flow cell; pump; detector;
light bulb; reagents; bubble or particle caught in the flow cell; dirty
optics or other detector issue
Old chemical or reagent; flow problem; contamination; leaking flow
cell
Carrier contamination; old carrier solution; inverse chemistry
Find the flow blockages
DI water (mL)
100
150
175
187.5
Common causes
on page 18. Make sure