HF scientific 19998 Triple Validation Turbidimeter - 0-100 NTU - Manual (Page 31)

TVT 1 (5/02) 25
Rev. 2.6 (.pdf)
10.0 Routine Maintenance
10.1 Cleaning the Optical Chamber (Sample Tube)
Proper measurement of turbidity requires that the sample tube be free of debris. Cleaning
the sample tube is accomplished by first purging the system:
1. Stop the flow of sample water to the TVT.
2. Remove the cleanout plug and then clean the interior of the sample tube with the
brush provided in the HF scientific, inc. calibration kit. If necessary, you may use
any common non-abrasive detergent to help in the removal of any residual buildup on
the sample tube.
3. Allow the sample tube to drain and then re-attach the flow of sample water to the
TVT. Allow enough sample water to flow through the instrument to achieve a stable
reading prior to placing the TVT back into routine operation.
10.2 Replacing the Desiccant Cartridge
Proper use of the supplied desiccant cartridge is essential in maintaining the performance
of the instrument. The desiccant cartridge has been designed to have a long life.
Replacement of the desiccant cartridge may be needed if water enters the enclosure, or if
the enclosure is opened for an extended period. It is also essential that all enclosure seals
are maintained. The desiccant cartridge should be replaced when the color of the
desiccant (as viewed through the sight glass) has turned pink.
The desiccant cartridge is located on the lower right side of the front display of the
instrument (see Figure 6). To remove the old desiccant cartridge, simply unscrew the
cartridge from the front of the case by rotating the cartridge counter-clockwise (see
Figure 6). Once removed, place the new cartridge into the instrument with the reverse
movements. Then continue using the instrument as normally instructed.
Figure 6: Removal of the Desiccant Cartridge