Extech HT30 Operating Manual

User's Manual

Heat Stress WBGT Meter
Model HT30

Warranty

EXTECH INSTRUMENTS CORPORATION warrants this instrument to be free of defects in

parts and workmanship for one year from date of shipment (a six month limited warranty
applies to sensors and cables). If it should become necessary to return the instrument for
service during or beyond the warranty period, contact the Customer Service Department at
[phone] ext. 210 for authorization or visit our website www.extech.com
information. A Return Authorization (RA) number must be issued before any product is
returned to Extech. The sender is responsible for shipping charges, freight, insurance and
proper packaging to prevent damage in transit. This warranty does not apply to defects
resulting from action of the user such as misuse, improper wiring, operation outside of
specification, improper maintenance or repair, or unauthorized modification. Extech
specifically disclaims any implied warranties or merchantability or fitness for a specific
purpose and will not be liable for any direct, indirect, incidental or consequential damages.
Extech's total liability is limited to repair or replacement of the product. The warranty set
forth above is inclusive and no other warranty, whether written or oral, is expressed or
implied.

for contact

Introduction

Congratulations on your purchase of Heat Stress WBGT (Wet Bulb Globe Temperature)
Meter. This meter measures and displays Heat Stress Index (WBGT), which is how hot it
feels when humidity is combined with temperature, air movement, and direct or radiant
sunlight. Black Globe Temperature (TG) monitors the effects of direct solar radiation on an
exposed surface. It also measures air temperature (TA) and Relative Humidity (RH).
Additional features include: selectable units of °F/°C, Auto power off with override, and a
built-in RS-232 interface with optional 407752 Windows® software. This meter is shipped
fully tested and calibrated and, with proper use, will provide years of reliable service.

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HT30 V3.0 08/07

Meter Description

1. Black Globe temperature sensor

2. RH and Temperature sensors with protective cover

3. LCD display

4.

/SET

5. NEXT

6. MODE/

7. RS-232 interface

8. Battery compartment (on rear)

DISPLAY

Symbol Function

WBGT Wet Bulb Globe Temperature
TG Black Globe Temperature
TA Air Temperature
RH% Relative Humidity
OUT Indoor (no sun)
IN Outdoor (in full sun)
C/F Celsius/Fahrenheit

Low Battery indicator

S

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HT30 V3.0 08/07

Meter Operation

1. Press the /SET button to power the instrument on/off.

2. Slide down the protective sensor cover before taking measurements.

3. Press the MODE/
Temperature Heat Index (WBGT), Air Temperature (TA), Black Globe Temperature
(TG), or Relative Humidity (RH). An icon will appear in the display indicating the
current selection.

4. To select the preferred temperature unit (°F or °C), simultaneously press and release
the MODE/

5. The meter measures WGBT index with (OUT) or without (IN) direct sun exposure.
Hold down the MODE/

IN or OUT icon will appear in the display.

Alarm Setting

The HT30 has a user settable heat stress index alarm. The HT30 will emit an audible beep
when the heat stress index (WBGT) reaches the level previously set by the user. The
alarm will continue beep until the measured heat stress index temperature falls below the
alarm level set by the user, or the meter is turned off. The setting range is from 68.0 to

99.0°F (20.0 to 37.2°C).

1. To enter the alarm setup mode, hold down the

when turning the meter on.

2. The current alarm setting will be displayed with the most significant digit blinking.

3. Use the MODE/

4. To set the next digit, momentarily press the NEXT button.

5. After all of the digits are set, press and hold the NEXT button for 2 seconds to return
to the measuring mode.

NOTE: The OUT icon will appear in the display If the new setting is out of the setting range
of the alarm.

Sbutton to select the desired display mode: Wet Bulb Globe

Sand NEXT buttons. The F or C icon will appear in the display.

S for more than 1 second to alternate between settings. The

/SET button for more than 2 seconds

Sbutton to increment the digit.

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HT30 V3.0 08/07