General tools EP8711P User Manual

6-IN-1

IN-DUCT DIGITAL

PSYCHROMETER

WITH ENTHALPY

USER’S MANUAL

EP8711P

Please read this manual carefully and

thoroughly before using this product.

TABLE OF CONTENTS

Introduction . . . . . . . . . . . . . . . . . . . . 2 –4

Key Features . . . . . . . . . . . . . . . . . . . . . . . 4

What’s in the Package . . . . . . . . . . . . . . . 5

Product Overview . . . . . . . . . . . . . . . . 5 –7

Setup Instructions . . . . . . . . . . . . . . . . . . 8

Install Batteries . . . . . . . . . . . . . . . . . . . 8

Operating Instructions . . . . . . . . . . . 8 – 10

Specifications . . . . . . . . . . . . . . . . . . . . . 11

Operating & Maintenance Tips . . . . . . . . 12

Warranty Information . . . . . . . . . . . 13 – 14

Return for Repair Policy . . . . . . . . . . . . . 14

INTRODUCTION

Thank you for purchasing General Tools
& Instruments’ EP8711P 6-in-1 In-duct
Digital Psychrometer with Enthalpy. Please
read this user’s manual carefully and
thoroughly before using the instrument.

The EP8711P can measure any
environment’s ambient temperature,
relative humidity (RH), dew point and wet
bulb temperatures, absolute humidity
(mixing ratio) and enthalpy of vaporization.
These measurements are typically made by
three groups of users:

• Water damage restoration contractors

• HVAC/R system installers and technicians

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• 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
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.

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An environment's absolute humidity level
(or mixing ratio) can be measured and
expressed in units of grains per pound
(GPP) or g/kg. GPP is a more useful
moisture metric than RH to water damage
remediators. Using RH alone, a remediator
might unknowingly introduce moist air—
with a low RH but a high GPP—during a
job’s drying phase.

The sixth environmental parameter that the
EP8711P can measure is enthalpy. Enthalpy
is a measure of the amount of energy
needed to change the state of a substance
from a solid to a liquid or from a liquid to a
gas. The most common application for the
EP8711P's enthalpy-calculating algorithm is
measuring the enthalpy of vaporization of
air in an HVAC/R system duct.

The EP8711P is powered by (3) “AAA”
batteries (included).

KEY FEATURES

• Integral 6 in. long sensor-tipped probe for
measuring conditions inside ductwork.
Probe swivels, increasing placement
options.

• Choice of Imperial or metric units for all
measured parameters except RH

• 4-digit LCD

• 2-minute Auto Power Off (APO) function

• Low battery indicator

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WHAT’S IN THE PACKAGE

The EP8711P comes fully assembled in a
blister pack along with a rubber bushing for
inserting the probe into ductwork, (3) “AAA”
batteries and this user’s manual.

PRODUCT OVERVIEW

Figure 1 shows all of the controls, indicators
and physical structures on the front and
back of the EP8711P. 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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