User's Guide Precision Hygro-Thermometer Model RH490 Introduction Congratulations on your purchase of the Extech RH490 Precision Hygro-Thermometer. This device measures Humidity, Air Temperature, Dew Point temperature, Wet Bulb temperature and Grains of Water Vapor per Pound of Air. Advanced features include Data Hold, Auto Power Off, and MAX/MIN reading. This meter is shipped fully tested and calibrated and with proper use will provide years of reliable service. Meter Description 1. Humidity & Temperature Sensor 2. LCD Display 3. Power ON/OFF button 4. °F/°C/WBT (wet bulb)/Dew Point button 5. Hold/MIN-MAX button 6. %RH, GPP, g/Kg, Backlight button 1 2 3 Note: The battery compartment is located on the rear of the instrument 6 5 4 Display Description 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. Relative Humidity % Dew Point Wet Bulb °C/°F Temp/WB/DP Display Maximum Minimum Low Battery Hold RH% Display Auto Off Grains per pound 2 RH490-EU-EN-V2.2-07/13 Operation Power Press the power button “ “ to turn power on or off. %RH 1. 2. 3. 4. 5. To select %RH measurement, press the “%RH/GPP/g/Kg” button. Hold the probe in the area to be tested. Allow adequate time for readings to stabilize. The Relative Humidity measurement appears in the top display. Pressing the “°F/°C/WBT/Dew Point” button toggles the lower display between Temperature (°F), Temperature (°C), Dew Point (°C), Dew Point (°F), Wet Bulb (°C) and Wet Bulb (°F). 6. Mixing Ratio (Grains Per Pound or Grams Per Kilograms) 1. To select GPP or g/kg measurement, press the “%RH/GPP/g/Kg” button. 2. 3. 4. 5. Hold the probe in the area to be tested. Allow adequate time for readings to stabilize. The GPP or g/Kg measurement appears in the top display. Pressing the “°F/°C/WBT/Dew Point” button toggles the lower display between Temperature (°F), Temperature (°C), Dew Point (°C), Dew Point (°F), Wet Bulb (°C) and Wet Bulb (°F). Dew Point 1. To select the Dew Point measurement, press the “°F/°C/WBT/Dew Point” button until DEWPOINT (°F or °C) appears in the lower right. 2. Dew Point temperature is now displayed. Wet Bulb 1. To select the Wet Bulb measurement, press the “°F/°C/WBT/Dew Point” button until WET BULB (°F or °C) appears in the lower right. 2. Wet Bulb temperature is now displayed. 3 RH490-EU-EN-V2.2-07/13 Temperature 1. 2. To select the temperature measurement, press the “°F/°C/WBT/Dew Point” button until “°C” or “°F” appears in the lower right. Temperature is now displayed. Data Hold 1. 2. Press the ”H MAX MIN” button momentarily to freeze the displayed readings. ”HOLD” will appear on the upper left-hand side of the display. Press the ”H MAX MIN” button three more times to return to normal operation. (Steps through MAX and MIN) Minimum (MIN) Maximum (MAX) Function The MIN/MAX mode allows the user to view only the lowest (MIN) or highest (MAX) readings. 1. Press the ”H MAX MIN” button twice and “MIN” appears on the display. The LCD is now displaying the minimum value recorded in both the top and bottom display. The display will not change until a lower reading is registered. 2. Press the ”H MAX MIN” button again and “MAX” appears on the display. The LCD is now displaying the maximum value recorded in both the top and bottom display. The display will not change until a higher reading is registered. 3. To exit the MIN/MAX mode, press the ”H MAX MIN” button again. The “MAX” icon will disappear. Note: Max and Min values are recorded into memory while the meter is on. The values are erased when power is turned off. Backlight Press and hold the light button “ hold the light button “ until the backlight turns on. To turn the backlight off, press and “ until the backlight turns off. Automatic Power OFF The meter has a default setting that automatically shuts the meter off after 10 minutes (indicated by the symbol on the display). This battery saving feature can be disabled. To disable the auto power off function, press and hold the ”H MAX MIN” hold button while powering on. The symbol will not appear when auto power off has been disabled. The meter will revert to the default auto-off mode when powered off. 4 RH490-EU-EN-V2.2-07/13 Maintenance Cleaning and storage 1. The meter should be cleaned with a damp cloth and mild detergent when necessary. Do not use solvents or abrasives. 2. Store the meter in an area with moderate temperature and humidity (refer to the operating and storage range in the specifications chart earlier in this manual). Battery Replacement When the battery becomes weak the “ “ battery symbol will appear on the LCD. Replace the 9 Volt battery by removing the Philips head screw holding the rear battery compartment cover to access the battery compartment. Ensure that the compartment cover is securely fastened when finished. You, as the end user, are legally bound (Battery ordinance) to return all used batteries and accumulators; disposal in the household garbage is prohibited! You can hand over your used batteries / accumulators at collection points in your community or wherever batteries / accumulators are sold! Disposal: Follow the valid legal stipulations in respect of the disposal of the device at the end of its lifecycle Specifications Function Range and Resolution Accuracy Humidity 0.0 to 10.0%RH ±3%RH Temperature 10.0 to 90.0%RH ±2%RH 90.0 to 100.0%RH ±3%RH o ±1.5 C o ±2.7 F o o ±1 C o ±1.8 F o ±1.5 C o ±2.7 F -30.0 to -20.0 C o -22.0 to – 4.0 F o -19.9 to 70.0 C o -3.9 to 158.0 F o 70.1 to 100.0 C o 158.1 to 199.0 F Wet Bulb 0 to 80°C (32 to 176°F) Dew Point -30 to 100°C (-22 to 199°F) 0 to 1120 GPP (grains per pound) Mixing Ratio Calculated from RH and air temperature measurements 0 to 160 g/kg (grams per kilogram) Display Dual LCD Response Time: <30 seconds (90% of final value in moving air) Operating Conditions 32 to 122 F (0 to 50 C); < 80% RH non-condensing o o o o Storage Conditions -40 to 185 F (-40 to 85 C); <99% RH non-condensing Power Supply 9 Volt battery Battery Life Approx. 24 hours Dimensions / Weight 7.8 x 1.7 x 1.3” (200 x 45 x 33mm); 7 oz. (200g) Copyright © 2013 FLIR Systems, Inc. All rights reserved including the right of reproduction in whole or in part in any form www.extech.com 5 RH490-EU-EN-V2.2-07/13