The UNI-T UT309C professional infrared thermometer combines industrial-grade durability with mid-range temperature measurement capabilities in a versatile, reliable package. Engineered to meet the rigorous IP65 protection rating and featuring an impressive 3-meter drop resistance, this thermometer delivers consistent performance in challenging work environments. With its 12:1 distance-to-spot ratio, expanded temperature range of -35°C to 650°C (-31°F to 1202°F), and dual laser targeting system, the UT309C provides the precision and reliability that maintenance professionals, HVACR technicians, and industrial inspectors require for accurate non-contact temperature measurement.
The UNI-T UT309C is built to withstand the demands of industrial and commercial work environments with its exceptional IP65 protection rating, providing complete protection against dust and water jets from any direction. The reinforced housing withstands drops of up to 3 meters onto concrete, ensuring reliability in even the most challenging conditions. This rugged construction eliminates downtime from accidental damage, making the UT309C a dependable tool for professionals working in harsh environments.
Every aspect of the UT309C has been engineered for long-term reliability, from its sealed button interfaces to its impact-resistant housing. This focus on durability ensures consistent performance and measurement accuracy throughout years of field use, delivering excellent value for professionals who depend on their tools in demanding work situations.
With its wide measurement range from -35°C to 650°C (-31°F to 1202°F), the UT309C handles most industrial and commercial temperature measurement tasks. The thermometer maintains accuracy of ±1.8°C or ±1.8% across its range, ensuring reliable readings for critical diagnostic and maintenance applications.
The adjustable emissivity settings (0.1-1.0) allow you to calibrate the device for different material surfaces, from highly reflective metals to matte-finished components. This versatility ensures accurate measurements regardless of the surface characteristics, making the UT309C adaptable to diverse measurement scenarios across multiple industries and applications.
The UT309C features a precision dual laser targeting system that clearly defines the measurement area boundaries, eliminating guesswork and ensuring consistent readings regardless of the operator. By visually indicating the exact area being measured, the dual laser system helps technicians target specific components within complex systems or identify hot spots in electrical panels and mechanical equipment.
The 12:1 distance-to-spot ratio provides a good balance between measurement distance and accuracy, allowing technicians to maintain a safe distance from hot or energized equipment while still obtaining precise readings. This optical resolution is ideal for most commercial and industrial applications where moderate measurement distances are typical.
The UT309C incorporates an innovative LED indicator system that provides immediate visual feedback on temperature conditions. The high-temperature (red) and low-temperature (blue) indicators allow technicians to quickly identify temperature excursions without having to interpret numerical values, improving reaction time to critical conditions and enhancing workflow efficiency during inspection sequences.
This visual alert system complements the standard LCD display, which features backlight functionality for clear visibility in low-light environments. Together, these display elements ensure that critical temperature information is always readily available to the operator, regardless of ambient lighting conditions.
HVAC technicians rely on the UT309C for diagnosing system performance, verifying temperature differentials across components, and identifying efficiency losses throughout heating, ventilation, and air conditioning systems. The adjustable emissivity settings ensure accurate readings on various system components from metal ductwork to compressor housings, while the MAX/MIN/AVG functions help identify inconsistent performance issues across complex systems.
The UT309C enables electrical maintenance professionals to safely detect overheating connections, load imbalances, and potential failure points in distribution panels, motor controls, and power systems. The dual laser targeting system ensures precise measurement of specific components within crowded electrical panels, while the high/low temperature indicators provide immediate visual feedback on critical conditions that could lead to system failure or safety hazards.
Automotive technicians use the UT309C to diagnose engine performance issues, check cooling system operation, verify catalytic converter efficiency, and identify brake system problems. The thermometer's durable construction withstands the harsh environment of repair shops, while its rapid response time of 250ms allows for efficient scanning of vehicle systems during diagnostic procedures.
Industrial maintenance technicians depend on the UT309C for monitoring process equipment including pumps, motors, bearings, and heat exchangers. The lock measurement function enables continuous temperature monitoring during equipment operation, while the durable IP65 construction ensures reliable performance even in wet, dusty processing environments.
The UNI-T UT309 series includes multiple professional-grade infrared thermometers designed to meet diverse industrial requirements. Understanding the differences between models will help you select the optimal tool for your specific applications:
| Specification | UNI-T UT309A | UNI-T UT309C | UNI-T UT309E |
| Temperature Range | -35°C to 450°C (-31°F to 842°F) |
-35°C to 650°C (-31°F to 1202°F) |
-35°C to 850°C (-31°F to 1562°F) |
| Distance-to-Spot Ratio | 10:1 | 12:1 | 20:1 |
| Emissivity | Fixed at 0.95 | Adjustable 0.1-1.0 | Adjustable 0.1-1.0 |
| Laser Type | Single | Dual | Dual |
| Display Type | Standard LCD | Standard LCD | Color EBTN |
| Data Storage | None | None | 99 readings with date/time |
| Scheduled/Monitoring Measurement | No | No | Yes |
| Environmental Protection | IP65, 3m drop proof | IP65, 3m drop proof | IP65, 3m drop proof |
| Best For | Basic maintenance, general inspection tasks | Intermediate applications requiring adjustable emissivity | Advanced industrial applications requiring maximum accuracy and data management |
The UT309C is the ideal choice when:
The UT309E may be more appropriate when:
The UT309A may be suitable when:
All models in the UT309 series share the same exceptional environmental protection (IP65 rating and 3-meter drop resistance) that has established UNI-T as a leader in durable professional measurement tools.
| Specification | Details |
| Certification | CE, UKCA |
| Temperature Range (°C) | -35°C to 650°C |
| Temperature Range (°F) | -31°F to 1202°F |
| Distance-to-Spot Ratio | 12:1 |
| Emissivity | 0.1-1 adjustable |
| Accuracy (°C) | ±1.8°C or ±1.8% (whichever is greater) |
| Accuracy (°F) | ±3.6°F or ±1.8% (whichever is greater) |
| Resolution | 0.1°C |
| Response Time | 250ms (95% of reading) |
| Spectral Response | 8μm-14μm |
| Laser Type | Dual, Class 2 |
| Laser Power | <1mW |
| Laser Wavelength | 630nm-670nm |
| Display Type | LCD with backlight |
| Display Size | 32 x 29mm |
| IP Rating | IP65 (dust-tight and protected against water jets) |
| Drop Resistance | 3 meters |
| Power Source | 9V battery (6F22) |
| Product Size | 189 x 118 x 55mm |
| Product Weight | 292g |
"The UT309C has become an indispensable tool for our maintenance team. The dual laser targeting makes it easy to get consistent readings, even when different technicians are performing the inspections. We've accidentally dropped it several times on concrete floors, and it continues to work perfectly—the durability claims are definitely legitimate." - Robert T., Maintenance Supervisor
"As an HVAC contractor, I need a thermometer that can handle everything from checking supply temperatures to troubleshooting compressors. The adjustable emissivity on the UT309C lets me get accurate readings on different surfaces, and the IP65 rating means I don't worry about using it in wet conditions. The value for the price is outstanding." - Sophia N., HVAC Technician
"Our automotive shop uses the UT309C daily for diagnostics on everything from cooling systems to catalytic converters. The high/low temperature indicators are surprisingly useful for quickly identifying problem areas, and the durability has been impressive in our rough shop environment. It's the perfect balance of features and value." - Marcus W., Automotive Service Manager
The UNI-T UT309C includes a comprehensive 1-year manufacturer's warranty. Our dedicated technical support team is available to assist with application-specific questions and ensure you maximize the value of your professional measurement investment.
The dual laser system projects two points that indicate the outer edges of the measurement area, allowing you to visualize exactly what surface area is being measured. This eliminates guesswork and ensures consistent targeting of specific components, improving measurement repeatability and reducing operator error compared to single-laser systems that only indicate the center point of the measurement area.
The IP65 rating means the UT309C is completely protected against dust ingress (the "6") and protected against low-pressure water jets from any direction (the "5"). In practical terms, this means the thermometer can be used safely in dusty industrial environments and will continue to function reliably even in rainy conditions or when exposed to water spray during cleaning operations. This level of protection significantly extends the usable life of the instrument in harsh working conditions.
A 12:1 distance-to-spot ratio means that at a distance of 12 inches, the thermometer measures a 1-inch diameter spot. For accurate measurements, the target should completely fill this spot size. In practical terms, this ratio allows you to measure a 1-inch target from up to 12 inches away, a 2-inch target from 24 inches away, and so on. For most industrial and commercial applications, this provides a good balance between measurement distance and target precision.
The UT309C includes an emissivity table in the user manual for common materials. For the most accurate results with unknown materials, you can use the comparative technique: measure the material with a contact thermometer, then adjust the emissivity setting until the infrared reading matches the known temperature. For common materials, typical emissivity values include: oxidized metals (0.2-0.4), painted surfaces (0.9), rubber (0.95), water (0.95), and most non-metallic surfaces (0.95).
While the UT309C has the technical capability to measure temperatures in the range needed for food service or basic medical screening, we recommend specialized models specifically designed and calibrated for these applications. The UT309C is optimized for industrial and maintenance applications rather than food safety compliance or medical screening, where different calibration standards and features may be required.
Experience the perfect balance of durability, precision, and value with the UNI-T UT309C professional infrared thermometer. Designed for professionals who need reliable performance in demanding environments without compromising on essential features, the UT309C delivers the measurement accuracy and rugged reliability that today's maintenance professionals depend on.
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