[. . . ] 0 to 50°C (32 to 122°F); max 95% RH non-condensing 1 x 9 volt After 10' of non-use in measurement mode; after 1 hour of non-use in calibration mode; with last reading reminder. CAL CHECK key: press to perform the validation of the meter, or press and hold for three seconds to enter calibration mode. ZERO/CFM key: press to zero the meter prior to measurement, to confirm edited values or to confirm factory calibration restore. [. . . ] If results are still found out of specifications then recalibrate the instrument. 9 CALIBRATION Note: It is possible to interrupt the calibration procedure at any time by pressing CAL CHECK or ON/OFF keys. 2· When the beeper sounds briefly and the LCD displays dashes, the meter is ready. 3· Press and hold CAL CHECK for three seconds to enter calibration mode. 4· Place the CAL CHECKTM Standard HI 96749-11 Cuvette A into the cuvette holder and ensure that the notch on the cap is positioned securely into the groove. 5· Press ZERO/CFM and the lamp, cuvette and detector icons will appear on the display, depending on the measurement phase. 6· After a few seconds the display will show "-0. 0-". 8· Place the CAL CHECKTM Standard HI 96749-11 Cuvette B into the holder and ensure that the notch on the cap is positioned securely into the groove. 9· Press READ/ /TIMER and the lamp, cuvette and detector icons will appear on the display, depending on the measurement phase. 10·The instrument will show for three seconds the CAL CHECKTM standard value. Note: If the display shows "STD HIGH", the standard value was too high. If the display shows "STD LOW", the standard value was too low. Verify that both CAL CHECKTM Standard HI 96749-11 Cuvettes, A and B are free from fingerprints or dirt and that they are inserted correctly. 11·Then the date of last calibration (e. g. : "01. 08. 2009") appears on the display, or "01. 01. 2009" if the factory calibration was selected before. Calibration Validation and Calibration procedures Warning: do not validate or calibrate the instrument with standard solutions other than the Hanna CAL CHECKTM Standards, otherwise erroneous results will be obtained. For accurate validation and calibration results, please perform tests at room temperature (18 to 25°C; 64. 5 to 77. 0°F). Use the Hanna CAL CHECKTM cuvettes (see "Accessories") to validate or calibrate instruments. 2· When the beeper sounds briefly and the LCD displays dashes, the meter is ready. 3· Place the CAL CHECKTM Standard HI 96749-11 Cuvette A into the holder and ensure that the notch on the cap is positioned securely into the groove. [. . . ] 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. When shipping any instrument, make sure it is properly packaged for complete protection. [. . . ]