General EP8710 User manual

CALIBRATABLE
7-FUNCTION
PSYCHROMETER
USER’S MANUAL
EP8710
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 . . . . . . . . . . . . . . . . . . . 5
Product Overview . . . . . . . . . . . . . . . . 5 –8
Setup Instructions . . . . . . . . . . . . . . . 8 –9
Install Battery . . . . . . . . . . . . . . . . . 8 –9
Operating Instructions . . . . . . . . . . . 9 – 12
Making Basic Measurements . . . . 9 – 11
sing the External Temperature Probe .11
Tracking Min and Max Levels . . . . . . . 12
Calibrating the Meter . . . . . . . . . . . 13 – 16
Specifications . . . . . . . . . . . . . . . . . . . . . 17
Operating & Maintenance Tips . . . . . . . . 18
Warranty Information . . . . . . . . . . . . . . . 19
Return for Repair Policy . . . . . . . . . . . . . 20
INT ODUCTION
Thank you for purchasing General Tools
& Instruments’ EP8710 Calibratable
7-Function Psychrometer. Please read this
user’s manual carefully and thoroughly
before using the instrument.
The EP8710 can measure any
environment’s ambient temperature,
relative humidity (RH), dew point and wet
bulb temperatures and other condensation-
related parameters. 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. It is the lowest temperature that can be
reached under current ambient conditions
by the evaporation of water only. The wet
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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.
Because the EP8710 includes an external
temperature probe, the instrument can also
measure and display two additional
parameters of particular importance to
HVAC/R system installers and technicians:
1) the surface temperature of a solid object,
the object's internal temperature (if it can
be penetrated), or the temperature of a
liquid or gas
2) a solid object’s condensation
temperature—the difference between its
surface temperature and the dew point
temperature
The EP8710 is powered by one “9V” battery
(included).
KEY FEATU ES
• umbo backlit display with 2-line readout
• Field calibratable using optional 33% and
75% salts
• Data hold and Min/Max functions
• External probe for measuring internal and
surface temperatures of objects and fluids
• °F/°C switch
• 20-minute Auto Power Off function
• Low battery indicator
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WHAT’S IN THE BOX
The EP8710 comes fully assembled in a box
along with a sensor protection cap, an
external temperature probe, a “9V” battery
and this user’s manual.
P ODUCT OVE VIEW
Figure 1 shows all of the controls, indicators
and physical structures on the front, top and
bottom of the EP8710. 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 Instructions and Operating
Instructions.
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Fig. 1. The EP8710’s controls, in icators
an physical structures
A. Humidity and temperature sensors
B. LCD
C. (Power on/off) button
D.
HOLD button
E. (Ambient/dew point temperature)
button
6
J
B
F
I
A
D
C
EH
G

F. Battery compartment
G.
MAX/MIN button
H. Probe/condensation/wet bulb
temperature) button
I.
F/C button
. External temperature probe plugged into
jack on side of unit
Fig. 2. All possible isplay in ications an
their meanings
A. Low battery icon
B. Data hold indicator
C. Minimum reading indicator
D. Maximum reading indicator
E. °C indicator
F. °F indicator
G. Probe (T2)/wet bulb temperature readout
H. Wet bulb (Wb) temperature indicator
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I. Condensation temperature () indicator
(available only with external probe plugged
in). An object’s condensation temperature is
the difference between its surface
temperature and the dew point
temperature.
. Probe temperature (T2) indicator
(available only with external probe
plugged in)
K. Ambient (T1)/dew point temperature
readout
L. Dew point temperature indicator
M.⌬T indicator (available only with external
probe plugged in). ⌬T is the difference
between ambient temperature (T1) and
the surface or internal temperature (T2)
of a solid or fluid touched or penetrated
by the probe.
N. Ambient (T1) temperature indicator
O. Relative humidity (RH) readout
SETUP INST UCTIONS
INSTALL BATTERY
1. The meter’s battery compartment (Fig. 1,
Callout F) 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.
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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.
OPE ATING
INST UCTIONS
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 upper display will
immediately begin reading out the RH value
of the environment. The lower left display
will immediately begin reading out the
ambient temperature (indicated by the text
T1 at its left). The lower right display will
immediately begin reading out the wet
bulb temperature (indicated by the text
Wb at its left).
To isplay the ew point temperature
(instead of ambient temperature) on the lower
left readout, press the button. The
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reading will be accompanied by the symbol
DP at its left. To return to displaying ambient
temperature, press the button again.
By default, the EP8710 displays ambient,
dew point, wet bulb, and objects’ and fluids’
surface and internal temperatures in °C.
To switch to °F , press the F/C button.
To hold the readings on all three displays,
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 EP8710, the unit’s Auto Power
Off (APO) function will automatically shut
down the instrument if no front-panel
buttons are pressed within any 20-minute
period.
To isable the APO function , power
on the unit in a special way by pressing and
holding the
HOLD 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
HOLD button. The APO
function will be enabled the next time you
power on the unit in the normal way.
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