1. Introduction
The MESTEK IR01C is a professional non-contact infrared thermometer designed for accurate surface temperature measurement. It features a wide temperature range, adjustable emissivity, and a clear color LCD display, making it suitable for various applications from household cooking to industrial maintenance. This manual provides essential information for safe and effective operation of your device.
2. Safety Information
Please read and understand all safety warnings and operating instructions before using this device. Failure to do so may result in injury or damage to the device.
- Laser Safety: This device uses a Class 2 laser. Do not stare directly into the laser beam or direct it at people or animals. Avoid direct eye exposure.
- Temperature Measurement: This thermometer is designed for surface temperature measurement only. It is not intended for measuring human body temperature.
- Operating Environment: Do not use the device in environments with explosive gas, vapor, or dust.
- Maintenance: Do not attempt to disassemble or modify the device. Refer all servicing to qualified personnel.
- Battery Handling: Dispose of used batteries properly according to local regulations. Do not mix old and new batteries.
3. Setup
3.1 Battery Installation
The MESTEK IR01C requires two AAA batteries (included). To install or replace batteries:
- Locate the battery compartment cover on the handle of the device.
- Slide the cover open.
- Insert two AAA batteries, ensuring correct polarity (+/-).
- Close the battery compartment cover securely.

Figure 3.1: Internal components and battery placement. The device uses two AAA batteries.
4. Operating Instructions
4.1 Taking a Measurement
To measure the surface temperature of an object:
- Point the thermometer at the target object. Ensure the distance-to-spot ratio (D:S) of 12:1 is considered for accurate readings. For example, at 12 inches distance, the measurement spot diameter is 1 inch.
- Press and hold the trigger button. The laser pointer will activate (if enabled) to indicate the measurement area.
- The temperature reading will be displayed on the LCD screen instantly.
- Release the trigger button to hold the reading on the display. The device will automatically power off after 30 seconds of inactivity to conserve battery life.

Figure 4.1: Taking a high-precision temperature measurement.
4.2 Temperature Unit Conversion (°C/°F)
To switch between Celsius (°C) and Fahrenheit (°F):
- With the device powered on, press the 'MODE' button to cycle through available settings.
- Locate the unit selection option (usually indicated by °C/°F icon).
- Press the up/down arrow buttons to select your desired unit.

Figure 4.2: Freely convert temperature units between Celsius and Fahrenheit.
4.3 Adjustable Emissivity
Emissivity (ε) is the ability of a material to emit thermal energy. Different materials have different emissivities. For accurate readings, adjust the emissivity setting (range 0.1 to 1.0) to match the material being measured.
- Press the 'MODE' button until the emissivity setting (ε) is displayed.
- Use the up/down arrow buttons to adjust the emissivity value.
- Refer to the emissivity table in the appendix (if provided in the full manual) for common materials.

Figure 4.3: Adjustable emissivity for accurate measurements on various materials.
4.4 High/Low Temperature Alarm
The device can be set to alert you when the measured temperature exceeds or falls below a specified range.
- Press the 'MODE' button until the High (HI) or Low (LO) alarm setting is displayed.
- Use the up/down arrow buttons to set the desired high or low temperature threshold.
- When the measured temperature goes above the HI limit or below the LO limit, the alarm indicator (red light) will illuminate, and "Hi" or "Low" will be displayed on the screen.

Figure 4.4: High/Low temperature alarm in action, showing a red indicator for high temperature.
4.5 Additional Functions
- MAX/HOLD Data: The device can display the maximum temperature measured during a scan or hold the current reading.
- Backlight: The color LCD display has a backlight for improved visibility in low-light conditions. This can usually be toggled on/off via a dedicated button or through the 'MODE' settings.
- Humidity Measurement: The device includes a humidity sensor to measure current ambient humidity.
- Infrared Lamp (Laser Pointer): The laser pointer can be turned off for measurements where a laser beam is not desired or for increased safety.

Figure 4.5: Overview of practical functions including emissivity, LCD, humidity, and laser control.
5. Applications
The MESTEK IR01C infrared thermometer is versatile and can be used in a variety of settings:
- Cooking and Food Preparation: Measuring temperatures of ovens, grills, pizza stones, and food surfaces.
- Home Maintenance: Checking radiators, freezers, HVAC systems, and insulation.
- Automotive: Diagnosing engine components, tires, and other vehicle parts.
- Industrial Use: Monitoring electrical systems, mechanical equipment, and various industrial processes.

Figure 5.1: Diverse applications of the MESTEK IR01C thermometer.
6. Maintenance
6.1 Cleaning
To ensure accurate readings and prolong the life of your device:
- Clean the lens regularly with a soft, damp cloth. Do not use abrasive cleaners or solvents.
- Wipe the device body with a slightly damp cloth.
- Ensure the device is dry before storage.
6.2 Storage
Store the thermometer in a cool, dry place away from direct sunlight and extreme temperatures. Remove batteries if the device will not be used for an extended period.
7. Troubleshooting
If you encounter issues with your MESTEK IR01C, refer to the following common problems and solutions:
- No Display/Device Not Turning On:
- Check battery installation and polarity.
- Replace batteries with fresh AAA batteries.
- Inaccurate Readings:
- Ensure the lens is clean and free from obstructions.
- Adjust the emissivity setting to match the material being measured.
- Verify the distance-to-spot ratio (12:1) is appropriate for your measurement.
- Ensure the ambient temperature is within the operating range of the device.
- Laser Not Working:
- Check if the laser function is enabled in the device settings.
- Ensure batteries have sufficient power.
- "Low Battery" Indicator:
- Replace the AAA batteries immediately.
For further assistance, please contact MESTEK customer support.
8. Specifications

Figure 8.1: Key features and specifications of the MESTEK IR01C.
| Feature | Specification |
|---|---|
| Model | IR01C |
| Temperature Range | -50°C to 550°C (-58°F to 1022°F) |
| Accuracy | ±1.5% or ±2°C (whichever is greater) |
| Distance-to-Spot Ratio (D:S) | 12:1 |
| Emissivity | Adjustable 0.10 - 1.00 |
| Response Time | < 0.5 seconds |
| Spectral Response | 8-14μm |
| Laser Power | < 1mW (Class 2) |
| Display | Color LCD with Backlight |
| Temperature Units | Celsius (°C) / Fahrenheit (°F) |
| Special Features | High/Low Temperature Alarm, Data Hold, Max Value Display, Low Battery Indicator, Auto Power-Off (30s), Ambient Temperature, Relative Humidity Measurement |
| Power Supply | 2 x AAA Batteries |
| Material | Plastic |
| Certifications | CE, FCC, EMC, RoHS, EN61010-1, EN60825 |
9. Warranty and Support
MESTEK provides a 36-month after-sales service for this product, along with lifetime technical support. If you have any questions or require assistance, please contact MESTEK customer service through the retailer or official website.





