Hanna Instruments PCA 310 - Manual (Page 69)

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HI 70479 HI 70473 HI 70474 or HI 70475
TUBING REPLACEMENT
The remaining tubing in the analyzers should be replaced
every two months.
When installing new tubing it is helpful to dip them in hot
water before making the connections.
It is also recommended that one tube at a time is removed
and replaced.
Note: DPD reagent tubing may darken before the scheduled replace-
ment time, but this will not affect the instruments performance.
CLEANING MEASUREMENT CELL
In order to maintain the maximum reliability of measurements,
it is recommended to periodically clean the measurement cell.
In fact, the measurement cell could collect sediment or de-
velop a film growth on the inside walls. When the automatic
dirt compensation system detect the deposits presence, the
analyzer will show “Dirty cell” message.
The measurement could continue but cleaning is recommended
to avoid deposits that are harder to clean.
Thorough cleaning with a dilute acid solution and a cotton
swab is recommended monthly. Depending on sample condi-
tions at individual locations and absence of input filters, it
may be necessary to clean the cell on a weekly basis. This can
be determined by observing the cell condition when reagents
are changed.
It is also highly recommended to clean the cell every time you
turn the meter off. In such a way, scaling and molds growth
are prevented. Otherwise, subsequent cleaning might become
more difficult.
For cleaning procedure, remove the plastic cap placed on the
top of the measuring cell.
Add a few drops of 19.2N Sulfuric Acid solution or alcohol to
the cell.