CALIBRATABLE 4-FUNCTION THERMOHYGROMETER USER’S MANUAL EP8709 Please read this manual carefully and thoroughly before using this product.
TABLE OF CONTENTS Introduction . . . . . . . . . . . . . . . . . . 2 – 4 Key Features . . . . . . . . . . . . . . . . . . . . 4 What’s in the Box . . . . . . . . . . . . . . . . 4 Product Overview . . . . . . . . . . . . . 4 – 6 Setup Instructions . . . . . . . . . . . . . . . . 7 Install Battery . . . . . . . . . . . . . . . . . . 7 Operating Instructions . . . . . . . . 7 – 10 Making Basic Measurements . . . 7 – 9 Tracking Min and Max Levels . . 9 – 10 Calibrating the Meter . . . . . . . .
• Water damage restoration contractors • HVAC/R system installers and technicians • Professionals charged with monitoring and maintaining the environment of facilities such as office buildings, greenhouses, food and equipment storage facilities, wineries, freezers, shipping containers, computer rooms, labs, libraries, museums and saunas.
bulb temperature is the temperature you feel when your skin is wet and exposed to moving air as opposed to the actual air temperature—the dry bulb temperature. The EP8709 is powered by one “9V” battery (included).
A B F G H C D E I Fig. 1. The EP8709’s controls, indicators and physical structures A. Humidity and temperature sensors B. LCD C. (Power on/off) button D. F/C button E. WBT (wet bulb temperature) button F. DEW button G. HOLD button H. MAX/MIN button I.
J A B C D H E G I F Fig. 2. All possible display indications and their meanings A. Low battery icon B. Data hold indicator C. Maximum reading indicator D. Minimum reading indicator E. °C indicator F. °F indicator G. Wet bulb temperature indicator H. Dew point temperature indicator I. Temperature readout J.
SETUP INSTRUCTIONS INSTALL BATTERY 1. The meter’s battery compartment (Fig. 1, Callout I) is accessible from the bottom of the unit. Use a Phillips-head screwdriver to loosen the single screw in the back of the unit that holds the yellow battery compartment cover in place. Set the cover and screw aside. 2. Plug the included “9V” battery into the wired socket inside the compartment.
immediately begin reading out humidity and ambient temperature measurements made by the sensors at the top of the unit. To display the dew point temperature (instead of ambient temperature) on the lower readout, press the DEW button. The reading will be accompanied by the symbol DEW at its left. To return to displaying ambient temperature, press the DEW button again. To display the wet bulb temperature (instead of ambient temperature) on the lower readout, press the WBT button.
Off (APO) function will automatically shut down the instrument if no front-panel buttons are pressed within any 20-minute period. To disable the APO function, power on the unit in a special way by pressing and holding the DEW button while pressing the button. The LCD will confirm that you are disabling the APO function by displaying its complete set of icons (see Fig. 2) until you release the DEW button. The APO function will be enabled the next time you power on the unit in the normal way.
To display the minimum RH and ambient temperature values measured since the meter was powered on, press the MAX/MIN button again. The text MIN will replace MAX at the right of the RH readout and both readouts will indicate the lowest values (of RH and ambient temperature) measured during the current session. To return to displaying real-time RH and ambient temperature readings, press the MAX/MIN button a third time. The text MIN will disappear from the RH readout.
Before beginning the calibration procedure—which is a turnkey process but takes at least 80 minutes to complete—you must disable the APO function so the instrument can remain on for more than 20 minutes. To disable the APO function, power on the unit in a special way by pressing and holding the DEW button while pressing the button. Following is the calibration procedure: 1.
5. Remove the meter from the 33% salt bottle and again press, hold and release the DEW and F/C buttons at the same time. Doing so this time will cause _ _ _ .2 to appear on the lower readout. 6. Turn the unit upside-down and insert the sensor structure in the opening of the 75% salt bottle after removing the bottle’s cap. The fit should be tight, with no air leaking into the bottle. 7. Leave the meter upside-down in the 75% salt bottle for at least 40 minutes.
SPECIFICATIONS Temperature Measurement Range: 14° to 122°F (-10° to 50°C) Temperature Measurement Accuracy: 1.8°F (±1°C) Temperature Measurement Resolution: 0.1° RH Measurement Range: 0 to 99.9% RH Measurement Accuracy: ±3% from 5% to 95% RH RH Measurement Resolution: 0.1% Response Time: <80 seconds Display Size: 1.7 in. (43mm) diagonal Current Consumption: <15mA Battery Life: 60 hours (typical) Dimensions of Instrument: 7.56 x 2.40 x 1.57 in. (192 x 61 x 40mm) Dimensions of Box: 7.76 x 3.66 x 1.58 in.
OPERATING & MAINTENANCE TIPS When the icon appears at the upper right of the display (Fig. 2, Callout A), it’s time to replace the “9V” battery that powers the instrument (although measurements will remain valid for several hours after the icon first appears). To replace the battery, follow the instructions on page 7. To prevent dust and moisture from degrading the performance of the humidity and temperature sensors, after each measurement session rotate the sensor protection cap to close its three vents.
WARRANTY INFORMATION General Tools & Instruments’ (General’s) EP8709 Calibratable 4-Function ThermoHygrometer is warranted to the original purchaser to be free from defects in material and workmanship for a period of one year. Subject to certain restrictions, General will repair or replace this instrument if, after examination, the company determines it to be defective in material or workmanship.
RETURN FOR REPAIR POLICY Every effort has been made to provide you with a reliable product of superior quality.
