General EP8709 User manual

CALIBRATABLE
4-FUNCTION
THERMO-
HYGROMETER
USER’S MANUAL
EP8709
Please read this manual carefully and
thoroughly before using this product.
99 Washington Street
Melrose, MA 02176
Phone [phone]
Toll Free 1-800-517-8431
Visit us at www.TestEquipmentDepot.com

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
Operatin Instructions . . . . . . . . 7 – 10
Makin Basic Measurements . . . 7 –9
Trackin Min and Max Levels . . 9 – 10
Calibratin the Meter . . . . . . . . 10 – 12
Specifications . . . . . . . . . . . . . . . . . . 13
Operatin & Maintenance Tips . . . . . 14
Warranty Information . . . . . . . . . . . . 15
Return for Repair Policy . . . . . . . . . . 16
INTRODUCTION
Thank you for purchasing General Tools &
nstruments’ EP8709 Calibratable 4-Function
Thermo-Hygrometer. Please read this user’s
manual carefully and thoroughly before
using the instrument.
The EP8709 can measure any
environment’s ambient temperature,
relative humidity (RH), and dew point and
wet bulb temperatures. These
measurements are typically made by three
groups of users:
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• 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.
The dew point is the temperature below
which the water vapor in a volume of air at
a given constant barometric pressure will
condense into liquid water at the same rate
at which it evaporates. Condensed water is
called dew when it forms on a solid surface.
Another way to think of the dew point is as
an air saturation temperature associated
with relative humidity (RH). A high RH value
indicates that the dew point is close to the
current ambient air temperature. At 100%
RH, the dew point temperature is equal to
the ambient temperature because the air is
completely saturated with water.
The wet bulb temperature is the
temperature that a volume of air would
have if it were cooled to saturation (100%
RH) by the evaporation of water into it, with
the latent heat coming from the volume of
air. t is the lowest temperature that can be
reached under current ambient conditions
by the evaporation of water only. The wet
3

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).
KEY FEATURES
• Jumbo backlit display with 2-line readout
• Field calibratable using optional 33% and
75% salts
• Data hold and Min/Max functions
• °F/°C switch
• 20-minute Auto Power Off function
• Low battery indicator
WHAT’S IN THE BOX
The EP8709 comes fully assembled in a box
along with a sensor protection cap, a “9V”
battery and this user’s manual.
PRODUCT OVERVIEW
Figure 1 shows all of the controls, indicators
and physical structures on the front, top and
bottom of the EP8709. Figure 2 shows all
text and icons that could appear on the
unit’s LCD. Familiarize yourself with the
positions and functions of all buttons,
structures and icons before moving on to
the Setup nstructions and Operating
nstructions.
4

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
. Battery compartment
5
A
B
C
D
I
F
G
H
E

Fig. 2. All possi le 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
. Temperature readout
J. Relative humidity (RH) readout
6
A
B
C
D
J
H
G
I
E
F

SETUP INSTRUCTIONS
INSTALL BATTERY
1. The meter’s battery compartment (Fig. 1,
Callout ) 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. The
terminals of the battery and the socket
mate in only one way, with the smaller
male terminal plugging into the larger
female terminal.
3. Replace the battery compartment cover
and tighten the screw to secure it to the
housing.
OPERATING
INSTRUCTIONS
MAKING BASIC
MEASUREMENTS
Before making any measurements, rotate
the sensor protection cap with your thumb
and index finger so its three vents are open
to the ambient environment from both the
front and back. Press the button to
power on the meter. The dual displays will
7

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 ul temperature
(instead of ambient temperature) on the
lower readout, press the
WBT button. The
reading will be accompanied by the symbol
WBT at its left. To return to displaying
ambient temperature, press the
WBT button
again.
By default, the EP8709 displays ambient,
dew point and wet bulb temperatures in °F.
To switch to °C , press the F/C button.
To hold a pair of readings (RH + ambient/
dew point/wet bulb temperature), press the
HOLD button. The text HOLD will appear at
the right of the RH readout. To “unfreeze”
the display and resume showing real-time
readings, press the
HOLD button again. This
will cause
HOLD to disappear from the RH
readout.
Pressing any button turns on the green
backlight for 10 seconds.
To extend the life of the “9V” battery
powering the EP8709, the unit’s Auto Power
8

Off (APO) function will automatically shut
down the instrument if no front-panel
buttons are pressed within any 20-minute
period.
To disa le 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 power off the EP8709 , press and hold
the button for at least 3 seconds.
TRACKING MIN AND MAX LEVELS
After being powered on, the EP8709
automatically operates in “Recording” mode
for the purpose of tracking maximum and
minimum RH and ambient temperature
values over the duration of a measurement
“session”.
To display the maximum RH and am ient
temperature
values measured during the
current measurement session, press the
MAX/MIN button once. The text MAX will
appear at the right of the RH readout and
both readouts will indicate the highest
values (of RH and ambient temperature)
measured since 1) the meter was last
powered on, or 2) the Min/Max memory
was reset (by entering and exiting Min/Max
mode.)
9

To display the minimum RH and am ient
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. Exiting
Min/Max mode clears the Min/Max memory
and begins a new measurement session.
CALIBRATING THE METER
Your EP8709 was calibrated at the factory,
so its measurements should remain within
their specified tolerance for several years.
However, you can re-calibrate the unit
yourself to reassure yourself of the
accuracy of readings, especially after the
instrument has been operated for many
hours in a dusty environment.
To calibrate the EP8709, you must use
two jars of standard calibration salt: one
containing a 33% solution of MgCl and the
other a 75% solution of NaCl. Both are
available for purchase from General as
part numbers SKUs HR33 and HR75.
10

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 disa le 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. With the unit powered on and the APO
function disabled, rotate the sensor
protection cap to open its three vents
and expose the humidity sensor to the
environment.
2. Press and hold the
DEW and F/C buttons
at the same time, and then release them.
This will cause
_ _ _ . 1 to appear on the
lower readout.
3. Turn the unit upside-down and insert the
sensor structure in the opening of the
33% salt bottle after removing the bottle’s
cap. The fit should be tight, with no air
leaking into the bottle.
4. Leave the unit upside-down in the 33%
salt bottle for at least 40 minutes. The
calibration to 33% is fully automatic and
requires no interaction or checking by
you.
11

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.
The calibration to 75% is fully automatic
and requires no interaction or checking
by you.
8. The unit is calibrated when two cycles—
one at 33% and the other at 75%—have
been completed. t is important that the
33% calibration precede the 75%
calibration. Reversing the order, or
performing either calibration twice, will
produce an error message when the unit
is restarted.
12

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 nstrument:
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. (197 x 93 x 40mm)
Weight (without battery): 3.77 oz. (107g)
Power Source: (1) “9V” battery (included)
13

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.
Do not operate the EP8709 in the presence
of a flammable or explosive gas or near an
arc welder or induction heater.
After subjecting the unit to a large change
in ambient temperature, wait at least
30 minutes before making measurements
to guarantee the accuracy of readings.
Remove the battery when storing the unit
or when you do not expect to use it for an
extended period of time (months rather
than weeks).
Do not drop or disassemble the EP8709 or
immerse it in water.
14

WARRANTY
INFORMATION
General Tools & nstruments’ (General’s)
EP8709 Calibratable 4-Function Thermo-
Hygrometer 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.
This warranty does not apply to damages
that General determines to be from an
attempted repair by non-authorized
personnel or misuse, alterations, normal
wear and tear, or accidental damage. The
defective unit must be returned to General
Tools & nstruments or to a General-
authorized service center, freight prepaid
and insured.
Acceptance of the exclusive repair and
replacement remedies described herein is a
condition of the contract for purchase of this
product. n no event shall General be liable
for any incidental, special, consequential or
punitive damages, or for any cost, attorneys’
fees, expenses, or losses alleged to be a
consequence of damage due to failure of, or
defect in any product including, but not
limited to, any claims for loss of profits.
15

RETURN FOR REPAIR
POLICY
Every effort has been made to provide you
with a reliable product of superior quality.
However, in the event your instrument
requires repair, please contact our Customer
Service to obtain an RGA (Return Goods
Authorization) number before forwarding the
unit via prepaid freight to the attention of our
Service Center at this address:
General Tools & nstruments
75 Seaview Drive • Secaucus, NJ 07094
212-431-6100
Remember to include a copy of your proof
of purchase, your return address, and your
phone number and/or e-mail address.
16
Specifications subject to change without notice
©2015 GENERAL TOOLS & INSTRUMENTS
NOTICE - WE ARE NOT RESPONSIBLE FOR
TYPOGRAPHICAL ERRORS.
MAN# EP8709 07/15/15
General Tools & Instruments
GeneralToolsNYC
99 Washington Street
Melrose, MA 02176
Phone [phone]
Toll Free 1-800-517-8431
Visit us at www.TestEquipmentDepot.com