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DIGITAL
PSYCHROMETER
USER’S MANUAL
SAM990DW
Please read this manual
carefully and thoroughly
before using this product.
GENERAL TOOLS
& INSTRUMENTS
80 White Street
New York, NY 10013-3567
PHONE (212) 431-6100
FAX (212) 431-6499
TOLL FREE (800) 697-8665
e-mail:
sales@generaltools.com
www.generaltools.com
SAM990DW User’s Manual
Specifications subject to change
without notice
NOTICE - NOT RESPONSIBLE FOR
TYPOGRAPHICAL ERRORS.
©2014
GENERAL TOOLS & INSTRUMENTS
MAN# SAM990DW
7/11/14
General Tools & Instruments
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INTRODUCTION
Thank you for purchasing General Tools & Instruments’
(General’s) SAM990DW Digital Psychrometer.
The SAM990DW is a psychrometer because it can
measure relative humidity (RH) as well as ambient, Dew
Point and Wet Bulb temperatures.
The Dew Point (DP) temperature 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.
The Wet Bulb (WB) 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. The WB
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.
KEY FEATURES
• Measures and displays RH as a percentage + ambient,
DP and WB temperatures in °C or °F on a dual-readout
LCD
• Min/Max memory + data hold
• 20-minute Auto Power Off (APO)
• 1-year limited warranty
WHAT’S IN THE PACKAGE
The SAM990DW comes in a blister pack with two “AAA”
batteries. A hard copy of this user’s manual is inside the
fold-over blister card.
S