Extech Instruments RH25 User manual

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USERGUIDE

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HeatIndexPsychrometer

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ModelRH25

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2RH25‐EU‐ENv1.05/13

Introduction

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ThankyouforselectingtheExtechInstrumentsModelRH25HeatIndexPsychrometer.TheRH25

measuresTemperatureandRelativeHumidity(usingprecisioncapacitanceRHsensor).TheRH25

alsocalculatesanddisplaysHeatIndex,DewPoint,WetBulb,andWetBulbGlobetemperatures.

TheHighTemperatureAlarmfeaturealertstheuserwhenHeatIndexorWetBulbGlobelevels

exceeduser‐presetlimits.

DataHoldandMIN/MAX/AVGmemoryutilitiesmakeiteasiertorecallimportantdata.

Thisdeviceisshippedfullytestedandcalibratedand,withproperuse,willprovideyearsof

reliableservice.Pleasevisitourwebsite(www.extech.com)tocheckforthelatestversionofthis

UserGuide,ProductUpdates,andCustomerSupport.

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Description

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Meter

1. Sensorarea

2. Displayarea(LCD)

3. POWERbutton

4. HOLDbutton

5. MODEbutton

6. Batterycompartmentonrearofinstrument

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Display

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TEMP Temperature

AIRTAirTemperature

RHRelativeHumidity

HIHeatIndex

DPDewPointtemperature

WBWetBulbtemperature

WB/HIWetBulbGlobetemperature

MAXMaximumreadingmemory

MINMinimumreadingmemory

AVGAveragereadingmemory

HOLDDataHold(freezesdisplay)

BATLowBatterysymbol

%PercentunitsforRHreadings

oDegreessymbolfortemperatureunits

EUsedtodisplaytemperatureunitsCorF

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3RH25‐EU‐ENv1.05/13

Operation

Keypad

POWER:SwitchthemeterONorOFF;alsousedtoentertheMAX/MIN/AVGmemorymode.

HOLD:PresstoenterDataHold(readingfreezesondisplay).PressagaintoexitDataHold.

MODE:Presstostepthroughthemeasurementmodes:TEMP(Temperature),RH(Relative

Humidity),HI(HeatIndex),DP(DewPoint),(WB(WetBulb),andHI/WB(WetBulbGlobe).

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Poweringthemeter

PressPOWERtoswitchmeterON.Themetershowsalldisplayiconsmomentarilyasitswitches

ONandthentheTEMPiconandthetemperaturereadingwilldisplay.Themeterwillalsoemita

chirpsoundasitswitchesON.

ToswitchthemeterOFF,pressandholdthePOWERbuttonforatleast2seconds.

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MAX/MIN/AVGMemory

WiththemeterpoweredON,pressPOWERbuttonmomentarily.TheMAXiconwillappearand

themeterwilldisplayonlythehighestreading.

PressPOWERagain;theMINiconwillappearandthemeterwillonlydisplaythelowestreading.

PressPOWERagain;theAVGiconwillappearandmeterwillonlydisplaytheaveragereading.

PressPOWERagaintoexit(theMAX/MIN/AVGiconswillswitchOFF).

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DataHold

WiththemeterpoweredON,presstheHOLDbuttonmomentarily.TheHOLDiconwillappear

andthecurrentreadingwillfreezeonthedisplay.PressHOLDagaintoexit(theHOLDiconwill

switchOFF).

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AutomaticPowerOFF(Sleep)Mode

ThemeterswitchesOFFautomaticallyafter15minutesofinactivity.Todefeatthisfeature

temporarily:WiththemeterswitchedOFF,presstheHOLDandPOWERbuttonssimultaneously

untilthemeterdisplaysthescreenshownbelow.Now,theusermustswitchthemeterOFF

manuallybypressingandholdingthePOWERbuttonforatleast2seconds.Notethatthenext

timethemeter’spoweriscycled,theAutoPowerOFFutilitywillagainbeactive.

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4RH25‐EU‐ENv1.05/13

SelectingoC/oFunitsofmeasure

WiththemeterOFF,pressandholdthePOWERandMODEbuttonssimultaneouslyuntiltheunit

ofmeasureappearsonthelowerrightcorneroftheLCD.UsetheMODEbuttontoselectthe

desiredunitofmeasure(oCoroF).PressPOWERtwicetosteppastthealarmsettingsuntilthe

normalmeasurementmodeisdisplayed.

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HighAlarmforHeatIndexandWetBulbGlobetemperature

1. WiththemeterOFF,pressandholdthePOWERandMODEbuttonssimultaneouslyuntilthe

temperatureunit‘C’or‘F’appearsonthelowerrightcorneroftheLCD(ifdesired,usethe

MODEbuttontoselectthedesiredunitofmeasure).

2. PressthePOWERbuttontosteptotheHeatIndex(HI)AlarmON/OFFdisplay.

3. UsetheMODEbuttontoselectON(A‐on)orOFF(A‐oF);seedisplayexamplesbelow:

4. PressPOWERtosteptotheHeatIndextemperatureAlarmlimitvalue.Seeexamplebelow:



5. PresstheMODEbuttonmomentarilytochangethevalueinsmallsteps.Pressandholdthe

MODEbuttontoscrollquickly.

6. WhenthedesiredHeatTemperaturealarmlimitisdisplayed,pressthePOWERbuttonto

continuetotheWetBulbGlobetemperatureAlarmprogrammingscreens.

7. Repeatsteps3‐6toprogramtheWetBulbGlobetemperatureON/OFFandAlarmlimits.

UsethePOWERbuttonwhendonetostepbacktothenormaloperatingmode.

8. Thedefaultsettingsare27.8oC(82.0oF)forHeatIndextemperaturealarmlimitsand28.0oC

(82.4oF)forWetBulbGlobetemperaturealarmlimits

9. Wheneitheralarmlimitisexceeded,themetercontinuouslybeeps.Todeterminewhich

alarmissounding,checktheHI(HeatIndex)andWB/HI(WetBulbGlobe)temperature

displaystoseewhichunitofmeasureisblinking,thatwillindicatethetrippedalarm.

10. TosilenceanalarmtheusermusteitherswitchthealarmOFForchangeitsalarmlimitvalue.

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ErrorMessageDisplays

E‐2:HumiditySensorfailure.Replaceunit.

E‐3:TemperatureSensorfailure.Replaceunit.

E‐4:Temperatureover‐range;E‐5:Temperatureunder‐range

E‐6:Hardwarefailure.Replaceunit

5RH25‐EU‐ENv1.05/13

Appendices

AppendixA–HeatIndexbasedonTemperature(oF)vs.RelativeHumidity(%)

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Note:ItalicvaluesareHeatIndexbasedontheTemperature(leftcolumn)andRelativeHumidity(toprow).

oF90%80%70%60%50%40%

80oF858482818079

85oF1019692908684

90oF121113105999490

95oF13312211310598

100oF142129118109

105oF148133121

110oF135

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AppendixB–HeatIndexbasedonTemperature(oF)vs.DewPoint(DP)

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Note:ItalicvaluesareHeatIndexbasedontheTemperature(leftcolumn)andDewPoint(toprow).

oF55DP60DP65DP70DP75DP80DP85DP

80oF556065838487

85oF808081899399107

90oF848695100107117

95oF91101106114125

100oF113121131

105oF127138

110oF134145

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AppendixC–HeatIndexandHealthEffects

HeatIndexof80to90oF:Fatiguepossiblewithprolongedexposureandphysicalactivity

HeatIndexof90to105oF:Sunstroke,heatcramps,andheatexhaustionpossible

HeatIndexof105to130oF:Sunstroke,heatcramps,heatexhaustionlikely;heatstrokepossible

HeatIndexof130oForgreater:Heatstrokehighlylikelywithcontinuedexposure

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TheHeatIndexisdeterminedusingthedrybulbtemperatureandtherelativehumidity.Itis

basedonchartsavailablethroughtheU.S.NationalWeatherService.TheHeatIndexrepresents

howanaveragepersonfeelsrelativetoclimateconditions.Foragiventemperature,thehigher

thehumidity,thehighertheheatindexwillbe.



6RH25‐EU‐ENv1.05/13

BatteryReplacement

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Whenthelowbatteryicon(BAT)appearsontheLCD,theCR‐2032lithiumbuttonbatterymust

bereplaced.Thebatterycompartmentislocatedontherearofthemeter.

1. Useacointoturnthebatterycompartmentcovercounter‐clockwisetoopen.

2. Notetheposition,orientation,andpolarityoftheexistingbatteryinstallation.

3. ReplacetheCR‐2032Lithiumbatteryfollowingthesameposition,orientation,and

polarity.

4. Replacethebatterycompartmentcoverandsecureitusingacointoturnitclockwise

Neverdisposeofusedbatteriesorrechargeablebatteriesinhouseholdwaste.

Asconsumers,usersarelegallyrequiredtotakeusedbatteriestoappropriate

collectionsites,theretailstorewherethebatterieswerepurchased,orwherever

batteriesaresold.

Disposal:Donotdisposeofthisinstrumentinhouseholdwaste.Theuseris

obligatedtotakeend‐of‐lifedevicestoadesignatedcollectionpointforthedisposal

ofelectricalandelectronicequipment.

OtherBatterySafetyReminders

oNeverdisposeofbatteriesinafire.Batteriesmayexplodeorleak.

oNevermixbatterytypes.Alwaysinstallnewbatteriesofthesametype.

Specifications

Display  Multi‐functionLCD

Measurementranges

AirTemperature‐20to50oC(‐4to122oF)

HeatIndex  ‐46to205oC(‐50.8to401oF)

DewPoint ‐78to50oC(‐108.4to122oF)

WetBulb ‐20to50oC(‐4to122oF)

WetBulbGlobe‐25to54.5oC(‐13to130oF)

RelativeHumidity0to99.9%RH

Resolution 0.1oC/oF/%RH

Accuracy

Temperature ±0.6oC(1oF)

RelativeHumidity±3%RH@25oCfrom10to90%RHotherwise±5%RH

Powersupply 1xCR2032LithiumBattery

Dimensions 140x35x18mm(5.5x1.4x0.7")

Weight  50g(1.8oz.)

Allrightsreservedincludingtherightofreproductioninwholeorinpartinanyform

www.extech.com

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