English User's Manual

 Mini InfraRed Thermometer
with Laser Pointer
MODEL 42500
USER GUIDE Introduction
Congratulations on your purchase of the Model 42500 IR Thermometer. This thermometer makes noncontact (infrared) temperature measurements at the touch of a button. The built-in laser pointer
increases target accuracy while the backlit LCD and handy push-buttons combine for convenient,
ergonomic operation. 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.
Use extreme caution when the laser pointer beam is on
Do not point the beam toward anyone's eye or allow the beam to
strike the eye from a reflective surface
Do not use the laser near explosive gases or in other potentially
explosive areas
Meter Description
LCD Display
Function Buttons
Handle Grip
IR Sensor
Laser pointer beam
Measurement Trigger
Battery Compartment
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Operating Instructions
1. Hold the meter by its Handle Grip and point it toward the surface to be measured. Read the
Field of View section below for distance to target ratio information.
2. Pull and hold the Trigger to turn the meter on and begin testing. The display will light if the
battery is good. Replace the battery if the display does not light.
3. While continuing to pull the Trigger:
Push the Laser button to switch the laser pointer ON. When the laser is on, the laser
will appear on the LCD over the temperature reading. Aim the red beam
approximately a half inch below the point of test (pressing the Laser button again turns the
laser off).
Select the temperature units using the C / F button.
Push the backlight button to switch ON the LCD backlighting function.
4. Release the Trigger; the reading will hold for approximately 6 seconds, after which the meter will
automatically shut off.
5. The meter defaults to the programmed conditions in use when the meter was last switched off.
For example, if the laser is set to ON and the temperature units are set to F at the time the unit
is switched OFF, the unit will switch ON and use the same settings.
Over-range Indicator
If the temperature measurement exceeds 500°F (260°C), the thermometer will display dashes in
place of a temperature reading.
Field of View
The meter’s field of view is 6:1. For example, if the meter is 30cm (approx.12”) from the target
(spot), the diameter of the target must be at least 5cm (approx. 2”). Other distances are shown
below in the field of view diagram.
Note that measurements should normally be made closer than 60cm (approx. 2’) from the target.
The meter can measure from further distances but the measurement may be affected by external
sources of light. In addition, the spot size may be so large that it encompasses surface areas not
intended to be measured.
Diameter of Spot
1 cm
8 cm
4 cm
2 cm
Sensor beam
1,6 cm
Laser beam
6 cm
12 cm
24 cm
48 cm
Distance to Object
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Measurement Notes
1. The object under test should be larger than the spot (target) size calculated by the field of view
2. If the surface of the object under test is covered with frost, oil, grime, etc., clean before taking
3. If an object's surface is highly reflective apply masking tape or flat black paint to the surface
before measuring.
4. The meter may not make accurate measurements through transparent surfaces such as glass.
5. Steam, dust, smoke, etc. can obscure measurements.
6. The meter compensates for deviations in ambient temperature. It can, however, take up to 30
minutes for the meter to adjust to extremely wide ambient temperature changes.
7. To find a hot spot, aim the meter outside the area of interest then scan across (in an up and
down motion) until the hot spot is located.
Battery Replacement
When the low battery symbol
appears on the LCD, replace the meter’s 9V battery. The battery
compartment is located on the bottom of the meter's handle. Open the compartment by sliding the
battery compartment cover off in the direction of the arrow. Replace battery and re-install the battery
compartment cover.
You, as the end user, are legally bound (EU Battery ordinance) to return all used
batteries, disposal in the household garbage is prohibited! You can hand over
your used batteries / accumulators at collection points in your community or wherever
batteries / accumulators are sold!
Disposal: Follow the valid legal stipulations in respect of the disposal of the device at
the end of its lifecycle
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Infrared Thermometer Specifications
Range / Resolution
-20 to 260 C (-4 to 500 F)
1 C/F
± 2% of reading or ±2 C (4 F) whichever is greater, from 15 to
50 C (60 to 113 F)
± 3% of reading or ±3 C (6 F) whichever is greater, for remainder
of range: -20 to 260 C (-4 to 500 F)
Note: Accuracy is specified for the following ambient temperature
range: 18 to 28°C (64 to 82°F)
0.95 fixed value
Field of View
D/S = Approx. 6:1 ratio (D = distance, S = spot)
Laser power
Less than 1mW
Spectral response
6 to 14 m (wavelength)
General Specifications
1999 count, backlit LCD display with function indicators
Display rate
1 second approx.
Operating Temperature
0°C to 50°C (32°F to 122°F)
Operating Humidity
Max. 80% RH
Power Supply
9V battery
Automatic Power Off
Meter shuts off automatically after 6 seconds
140g (4.9 oz.)
170 x 44 x 40mm (6.7 x 1.7 x 1.6”)
Copyright © 2015 FLIR Systems, Inc. All rights reserved including the right of reproduction in whole or in part in any form www.extech.com 5
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