Plant & Works Engineering
Fast diagnosis
Published:  12 March, 2020

Professionals who install, inspect, and maintain heating, ventilation, air conditioning and refrigeration (HVAC/R) systems face a variety of challenges. In a single day, they might be part-electrician and work with electrical issues, be part-plumber and work with water or combustible gas related items travelling through pipework, or do both jobs and install an entire system. A thermal imaging camera can help HVAC/R professionals quickly determine the root cause of a problem, identify the faulty component and provide a level of trust that recommended repairs are indeed required. PWE reports.

Residential HVAC technicians are usually called to sites with a very general complaint that “the system isn’t working,” only to find issues extending from basic component failures to problems with the condensing unit, evaporator coils and the air handling system.

Commercial and industrial HVAC techs usually work on regularly scheduled maintenance of these systems to maintain operational efficiency. Off-schedule visits are also needed to diagnose and repair a specific problem that may arise and limit plant operations. Customers want to avoid downtime and budget maintenance and repair expenses. They want to know well in advance if something is going to fail, since the cost of downtime can be very high. In addition, the cost of the repair may require approvals to proceed.

The method used to diagnose temperature related issues most frequently is a spot temperature gun, which is inexpensive and easy to use. Unfortunately, the device’s accuracy is entirely dependent on the user aiming it correctly. These devices don’t visually show the user where components are hot; instead, the user has to guess where the problem may lie and aim the sensor at that component to measure its temperature.

HVAC technicians have recently started to use thermal imaging cameras to find problem areas in all areas of their work. These cameras work by detecting heat (or lack of heat) given off by an object. The sensor takes the energy and translates it into light. The viewer sees the light in a range of colours: red, orange and yellow indicates heat, while dark blue, black or purple signifies colder temperature.

Thermal imaging is valuable for the pure speed of which it can diagnose basic HVAC problems. Thermal imaging is a great tool for finding problems with fuses, breakers, connections, belts, bearings and hoses. It also helps see differential temperatures and find problems with the building construction that might have an impact on system performance. Whether the problem is a failing unit or one that is operating inefficiently, a thermal imaging camera can clearly show if a component is clogged or not working properly.

Similarly, a thermal imaging camera can be used to detect if the evaporating units are working up to par. For example, if the evaporator coil tubes are clogged, the camera can detect if the flow is uniform, or whether only half the coil is working properly.

An HVAC contractor can also diagnose issues associated with air conditioner units running inside a building. Using a thermal imaging camera, technicians can quickly scan every vent and register to see if the temperatures are uniform, or if any spots are too warm or too cold.

Thermal imaging also makes it easier to conduct troubleshooting activities, especially with the electrical side of HVAC/R systems. Thermal imaging will guide a technician to electrical components that may not be operating properly, whether they are overloaded or not operating at all. All operating circuits show some sort of heat during operations, but when several circuits look uniform, and one reads hotter or colder than the surrounding comparable items, it may be worth investigating.

Adding credibility

Another essential feature of thermal imaging is that it can be used to document existing issues. Showing images to customers can help support technicians’ recommendations for additional work that may be needed. Additionally, images may be collected over time and used to look at the long term “health” of a component, or establish operational norms of properly operating equipment and trend analysis.

Air leaks are clearly visible with thermal imaging. The cause may be old ductwork, leaky ductwork, improper insulation or connections between components, or faulty operation of components. These items are generally invisible without thermal imaging. A technician who shows the customer the problem visually to secure the work, fixes the issue, and follows up with a before/after image will be much more credible. Some HVAC technicians even insert a before and after picture on their invoice to provide assurance that the issue was corrected as diagnosed. Happy customers – who are confident in the work process – are customers who lead to referrals and repeat business.


When technicians can find (and display) an issue in minutes versus an hour of diagnostic testing, they can do the job faster and make more calls per day. At the same time they can use the thermal imaging tool to create a higher level of trust and prove to the customer’s satisfaction that the work recommended is necessary. HVAC contractors who use a thermal imaging camera will pay for the tool in as little as one to three days. Unlike many tools in a technician’s bag, thermal imaging cameras generate revenue by finding issues faster, verifying a job well done and creating life-long customer loyalty.

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