User manual HANNA INSTRUMENTS HI 991405

[. . . ] 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. If the repair is not covered by the warranty, you will be notified of the charges incurred. If the instrument is to be returned to Hanna Instruments, first obtain a Returned Goods Authorization Number from the Customer Service department and then send it with shipment costs prepaid. [. . . ] To change the temperature unit To change the temperature unit (from °C to °F), from measurement mode, press and hold the MODE button until "TEMP" and the current temperature unit are displayed on the lower LCD (E. g. Use the SET/HOLD button to change the temperature unit, and then press MODE button twice to return to normal measurement mode. To freeze the display Press and hold the SET/HOLD button for 2-3 seconds, until "HOLD" appears on the secondary display. Press either button to return to normal mode. Taking measurements Select the pH, EC or TDS mode with the SET/HOLD button. Immerse the probes in the solution to be tested. In order to ensure better accuracy, probes should not touch or stand close to the walls or bottom of the sample vessel. The pH, EC or TDS value automatically compensated for temperature is shown on the primary LCD while the secondary LCD shows the temperature of the sample. Measurements should be taken when the stability symbol on the top left of the LCD disappears. IMPORTANT NOTE Measurements have to be taken with both pH electrode and conductivity/temperature probe (also working as matching pin) immersed in the same vessel. To change the TDS conversion factor (CONV) and the temperature compensation coefficient (BETA) · From measurement mode, press and hold the MODE button until "TEMP" and the current temperature unit are displayed on the lower LCD (E. g. · Press the MODE button again to show the current conversion factor (E. g. · Use the SET/HOLD button to change the conversion factor. · Press the MODE button to show the current temperature coefficient (E. g. · Use the SET/HOLD button to change the value. · Press MODE to return to normal measuring mode. To turn the meter off Press the MODE button while in normal measurement mode. "OFF" will appear on the lower part of the display. The display still lits, until the power supply is connected. Notes: · Before taking any measurement make sure the meter has been calibrated. · To clear a previous calibration, press the MODE button after entering the calibration mode. The lower LCD will display "ESC" for 1 second and the meter will return to normal measurement mode. The "CAL" symbol on the LCD will disappear. [. . . ] NEVER USE DISTILLED OR DEIONIZED WATER FOR STORAGE PURPOSES. · If the electrode has been left dry, soak in a storage or pH 7 solution for at least one hour to reactivate it. · To prolong the life of the pH electrode, it is recommended to clean it monthly by immersing it in the HI 7061 cleaning solution for half an hour. Afterwards, rinse it thoroughly with tap water and recalibrate the meter. · For a two-point pH calibration, place the electrode and the probe in pH 7. 01 (or 6. 86 if you have selected the NIST buffer set). [. . . ]