Hach SP-510, Basic User Manual, Page: 22 / 188

Cause Solution
No stir bar is installed or more
than one stir bar is installed.
• Make sure that a stir bar is installed.
• Use a paper clip to retrieve the stir bar from the colorimeter and make sure
that multiple stir bars are not installed.
• If the stir bar does not operate, mix the sample manually after the reagents
have been added. Use the end of a wooden Q-tip and mix the reagents
approximately for 10 seconds. If the instrument gets a reading, the mixing is
not sufficient. Replace the stir coil. Additional information is available on the
manufacturer's website.
The instrument does not
receive any buffer or indicator
solution. Remove the two reagent lines from the Y connector. Only one drop of reagent
comes out per cycle. If no reagent comes out, examine the pressure plate.
Make sure that the pinch block is not overtightened and the reagent lines are
not pinched. Examine the back of the pinch block for grooves. Replace the
pinch block if necessary.
The chemistry does not operate
correctly. Mix 1-mL of each reagent and 80-mL of sample. A color change must show. If
no color change shows, replace the reagents.
The instrument does not
operate correctly. Pinch the sample inlet line to stop the sample flow. The next cycle reads soft. If
it does not read soft, examine the LED if it shows an orange light. Examine the
photocell and clean if necessary. After this cycle, the instrument reads hard
again.
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