User manual HANNA INSTRUMENTS HI 8731

[. . . ] This warranty is limited to repair or replacement free of charge. Damages due to accidents, misuse, tampering or lack of prescribed maintenance are not covered. If service is required, contact the dealer from whom you purchased the instrument. If under warranty, report the model number, date of purchase, serial number and the nature of the failure. [. . . ] · Connect the probe to the DIN socket on the top of the meter by aligning the pins with the socket and pushing in the plug. · Turn the meter on by pressing the ON/OFF key. · Immerse the tip of the probe into the sample to be tested. If possible, use plastic beakers to minimize any EMC interference. · Tap the probe lightly on the bottom of the beaker to remove any air bubbles which may be trapped inside. · Select the desired measurement range, by pressing the corresponding key: "S/cm" for EC or "ppm" for TDS. · Wait a couple of minutes for the temperature sensor to reach thermal equilibrium. The display will then show the measurement automatically temperature compensated for temperature with the appropriate indication: "S" symbol indicates the meter is in EC mode, while no symbol means that the meter is in TDS mode. CALIBRATION · Turn the meter on. · Pour a small quantity of HI 70039 (5000 S/cm) EC calibration solution or HI 70032 (1382 ppm) TDS calibration solution into a clean beaker. If possible, use plastic beakers to minimize any EMC interference. Note: The conversion factor between EC and TDS readings is made by a built-in circuit. Therefore, it is requested to calibrate only one range (EC or TDS), and the other range will be automatically calibrated. · Immerse the probe in the calibration solution and wait for a couple of minutes for thermal equilibrium to be reached. · Tap the probe on the bottom, then shake it, to make sure no air bubbles remain trapped inside the probe. · Press the "S/cm" (or "ppm") key. · Turn the EC/TDS calibration knob until the display shows the calibration solution value. Note: For best accuracy, the probe body should not touch nor stand close to the side walls of the beaker. PROBE MAINTENANCE Periodic Maintenance · Inspect the probe and the cable. The cable used for the connection to the meter must be intact and there must be no points of broken insulation on the cable or cracks on the probe stem or bulb. · Connector must be perfectly clean and dry. If any scratches or cracks are present, replace the electrode. Cleaning Procedure For better accuracy in measurements and to ensure a good performance of the probe, a frequent cleaning is recommended. · Immerse the tip of the probe in the HI 7061 cleaning solution for half an hour. [. . . ] When the low battery indication appears, only a few hours of working time are left. When the battery level is too low to ensure reliable measurements, the meter turns off. It is recommended to replace the battery immediately. Battery replacement must only take place in a nonhazardous area using a 9V alkaline battery. [. . . ]