Extech Instruments RH25 User Manual

2RH25‐EU‐ENv1.05/13
Introduction

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.

Description

Meter
1. Sensorarea
2. Displayarea(LCD)
3. POWERbutton
4. HOLDbutton
5. MODEbutton
6. Batterycompartmentonrearofinstrument

Display

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


Extech Instruments RH25 Specifications

Measurements

air temperature range	-20 to 50 °C (-4 to 122 °F)
heat index range	-46 to 205 °C (-50.8 to 401 °F)
dew point range	-78 to 50 °C (-108.4 to 122 °F)
wet bulb range	-20 to 50 °C (-4 to 122 °F)
wet bulb globe range	-25 to 54.5 °C (-13 to 130 °F)
relative humidity range	0 to 99.9% RH

Accuracy

temperature accuracy	±0.6 °C (1 °F)
relative humidity accuracy	±3% RH @ 25 °C from 10 to 90% RH otherwise ±5% RH

Power

power supply	1 x CR2032 Lithium Battery

Weight and Dimensions

dimensions	140 x 35 x 18 mm (5.5 x 1.4 x 0.7")
weight	50 g (1.8 oz.)