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:
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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.
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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.)
Copyright©2013FLIRSystems,Inc.
Allrightsreservedincludingtherightofreproductioninwholeorinpartinanyform
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