RH401 V1.5 8/08

3

Operation

Retractable Humidity and Air Temperature Sensor

Press down on the sensor, located at the top of the meter, to

release it. Humidity and air temperature will not be displayed if the

sensor is not extended.

After use, press the sensor into the stored (protected) position.

Power ON/OFF

Press the

(or the

button) to turn power on. The

meter will perform a short self-test when turned on.

Press and hold the

button for three seconds to turn power off.

Humidity and Air Temperature measurements

1. Hold the meter in the area to be tested.

2. Allow adequate time for readings to stabilize.

3. View the Relative Humidity measurement in the lower display.

4. View the Air (probe)Temperature measurement in the middle display

Wet Bulb and Dew Point measurements

1. To display the Dew Point measurement, press and hold the

button until the

symbol DP appears in the middle display.

2. Dew Point temperature is now displayed.

3. To display the Wet Bulb measurement, press and hold the

button until the

symbol Wb appears in the middle display .

4. Wet Bulb temperature is now displayed.

5. To display IR temp –DP temp (IR surface temperature-Dew Point), press and hold the

button for more than 2 seconds then press the IR Temp button. The reading

can now be viewed in the top display.

6. Press and hold the

button for more than 2 seconds to toggle the display back

to IR temperature.

Non-Contact InfraRed Surface Temperature measurements

1. Point the meter toward the surface to be measured.

2. Press and hold the

button.

3. View the temperature measurement in the upper display

4. Release the

nd the reading will be held on the display until a new reading is

taken.

5. While holding down the

button, press the

button to toggle the laser

targeting pointer on/off. The

symbol will appear in the middle left of the display

indicating that surface temperature measurement is active and the laser pointer is on.

WARNING! The Laser button

enables/disables the Laser pointer. When

enabled, each press of the

button turns on the Laser beam. Avoid looking directly

into the path of the Laser or pointing the Laser toward anyone’s eyes. Mirrored surfaces

near a measurement object can redirect the Laser, use extreme caution. Do not allow

the Laser beam to be directed toward explosive gases.

Sensor

Extended

Stored

Sensor

Press Here