User Manual

42280 V3.0 10/2007

Humidity Calibration

1. Turn on the meter and plug the humidity sensor probe into the 33% Calibration

Reference bottle.

2. Simultaneously press and hold the START-STOP and the SET buttons for at least 2

seconds to enter the 33% Calibration mode. The display ’32.8%’ will begin to flash on

the display.

3. Approximately 30 minutes later, the ’32.8%’ display will stop flashing, indicating that

the 33% calibration is complete

4. Plug the humidity sensor probe into the 75% Calibration Reference bottle.

5. Press and hold the START-STOP button for at least 2 seconds to enter the 75%

Calibration mode. The display ’75.3%’ will begin to flash on the display.

6. Approximately 30 minutes later, the display will stop flashing, indicating that the entire

calibration is complete. The meter will automatically return to the normal operating

mode

Calibration Notes:

• The user can exit the calibration without finishing by pressing the START-STOP

button for 2 seconds (before reaching step 6 above).

• For best accuracy, perform the calibration at room temperature.

• Calibration Reference bottles are available optionally through Extech

Instruments distributors