Elcometer 116A

Whirling Hygrometer

Operating Instructions

English

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EnglishR

is a registered trademark of Elcometer Limited.
All other trademarks acknowledged.
© Copyright Elcometer Limited. 2009.
All rights reserved. No part of this Document may be reproduced, transmitted, transcribed, stored (in a retrieval
system or otherwise) or translated into any language, in any form or by any means (electronic, mechanical,magnetic, optical, manual or otherwise) without the prior written permission of Elcometer Limited
A copy of this Instruction Manual is available for download on our Website via www.elcometer.com.
Doc.No. TMA-0457 Issue 01
Text with Cover No: 4817

116A_TMA_0457_00_01 (Part Spec 4817).fm Page 1 Monday, April 20, 2009 12:38 PMRCONTENTS
SectionPage

1Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2Using your Whirling Hygrometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4Technical specification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55Spares & accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66Related equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

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Thank you for your purchase of the Elcometer 116A Whirling Hygrometer (Psychrometer). Welcome toElcometer.
Elcometer are world leaders in the design, manufacture and supply of inspection equipment for coatingsand concrete. Our products cover all aspects of coating inspection, from development through application
to post application inspection.
The Elcometer 116A Whirling Hygrometer is a world beating product. With the purchase of this product you
now have access to the worldwide service and support network of Elcometer. For more information visit ourwebsite at www.elcometer.com

1 INTRODUCTION
The Elcometer 116A Whirling Hygrometer is designed to measure the ambient relative humidity from which
the dewpoint temperature can be calculated. The Elcometer 116A Whirling Hygrometer is scaled in degrees
Celsius. A simple Relative Humidity Guide is provided but more accurate results can be obtained using theElcometer 114 Dewpoint Calculator.
1.1 WHAT THE BOX CONTAINS• Elcometer 116A Whirling Hygrometer• Relative Humidity Guide• Operating Instructions

2

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2 USING YOUR WHIRLING HYGROMETER
1. Fill the reservoir with distilled water.
2. Check that the wick covers the bulb of the wet thermometer
fully and is saturated with water.

reservoir

dry bulb
thermometer

3. Hold the handle of the hygrometer and whirl it for 20 to 40
seconds.
4. Quickly read the wet thermometer and whirl the hygrometer
again.
5. Repeat steps 3 and 4 until consecutive readings are thesame. Read the wet & dry thermometers.
6. Calculate the wet bulb depression, ie, the difference between
the dry and wet bulb temperatures.

wickwet bulb
thermometer
Handle7. Use the table to find Relative Humidity (%RH).
Eg. Temperatures, dry 20°C, wet 15°C;
Depression (20-15) = 5°C; Relative Humidity: 59%(See value at intersection of dry bulb column and depression row)
To calculate Dewpoint:
On the bulb scale, use the wet bulb reading and move down the column to the Relative Humidity which
is closest to the calculated value, read depression. So if RH is 58%, depression is 4.5°C; Dewpoint =wet bulb - depression = 15 - 4.5 = 10.5°C.

3

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2.1 ACCURATE USE
To achieve an accurate measurement of wet bulb temperature :•Keep the wick clean, tight fitting, fully over the thermometer bulb and saturated with distilled water.

•Evaporate the maximum amount of water from the wet bulb by whirling the hygrometer faster than
180rev/min.

•Minimise the effect of your body by holding the hygrometer in front of you, facing the wind. On a still
day walk forwards while whirling.

•Reduce environmental effects by not whirling in direct sunlight or near heat sources.

•Read the wet bulb temperature as soon as whirling has stopped and do not touch the thermometer
while taking readings.

•Only use values when consecutive readings are the same.

Incorrect use of the hygrometer will result in the wet bulb temperature, and consequently %RH anddewpoint, being too high.
For greater calculation accuracy, use the Elcometer 114 Dewpoint calculator or psychrometric tables.

3 MAINTENANCE
Elcometer products are designed to give many years reliable service under normal operating and storage
conditions.

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4 TECHNICAL SPECIFICATION
Dimensions:

230 x 80 x 28mm

Range:-5°C to 50°C

Weight:300g (0.6lb)

Relative Humidity Table
Accuracy

Range%RH±2%

1 - 99%RH

Dewpoint±2°C

0 - 20°C

Dewpoint

±6°C

>20°C

Your Elcometer 116A Whirling Hygrometer may be packed in a cardboard and foam package. Please
ensure that this packaging is disposed of in an environmentally sensitive manner. Consult your local
Environmental Authority for further guidance.

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R5 SPARES & ACCESSORIES
Spirit Thermometer °C

T1164441-

Relative Humidity Table Card

T1164488-

Pack of 5 Wicks

T1164487-

Dewpoint Calculator

G114----2

To order spare parts, contact Elcometer, your local Elcometer supplier or visit www.elcometer.com

6 RELATED EQUIPMENT
In addition to the Elcometer 116A Whirling Hygrometer, Elcometer produces a range of Climatic Testing
equipment. Users of the Elcometer 116A Whirling Hygrometer may also benefit from the following
Elcometer product ranges :•Elcometer 319 Dewpoint meter•

Elcometer 113 Magnetic Thermometers•Elcometer 212 Digital Pocket Thermometer6