The ACHR News report on Trane's Cancoil acquisition covers a heat-transfer products manufacturer, and it describes the deal as including existing operations and "growing U.S. manufacturing operations." For a homeowner, the corporate paperwork matters less than the coil itself. The coil in your air handler either moves heat or it does not, and you can measure that yourself in about twenty minutes with two thermometers and a willingness to work in a cramped furnace closet.
What the Split Measures
With the system running in cooling mode, air leaving the indoor coil should be noticeably colder than air entering the return. The gap between those two temperatures is the temperature split, often called the delta-T. It is a quick read on how much heat the coil is pulling out of the house air. It is not a diagnosis. A healthy-looking split can still hide trouble elsewhere, and an unhealthy one usually starts with airflow long before it points at the coil.
Tools and Setup
You need two digital thermometers with remote probes. An infrared gun reads surface temperature, which is the wrong number for moving air, so leave it in the truck. Before you measure, change or inspect the filter, confirm that the return grilles are open and unblocked, and make sure no supply register near the air handler is closed. Set the thermostat well below room temperature so the system runs continuously. Let it run at least fifteen minutes before reading, because the first minutes reflect start-up conditions rather than steady operation.
Taking the Readings
Place the return probe in the airstream at the return grille nearest the air handler, or inside the return duct if you can reach it, keeping the probe clear of metal surfaces. Place the supply probe in the airflow at the supply register nearest the air handler, aimed into the stream rather than sitting against the grille edge. Shield both probes from direct sunlight and from the warm cabinet. Write down the time, the outdoor temperature, and whether the house feels humid, because those conditions move the number.
Reading the Result
Subtract the supply temperature from the return temperature. Many installers look for a split in the mid-teens to low twenties Fahrenheit, but the target that counts is the one listed for your model in the manufacturer's literature or on the commissioning sheet from the original install. Humid days shift the number because the coil spends energy removing moisture as well as lowering air temperature. Compare readings taken on similar days rather than chasing a single figure.
A low split usually means the coil is seeing too much air, too little heat, or both. Check the filter, the blower speed setting, closed registers, and any restriction in the return path first. A high split often points to weak airflow, with the coil running colder than it should while not moving enough air through the house. Airflow problems are the cheapest to rule out, and they cause more false alarms than most homeowners expect.
Where to Stop
Treat the air handler as live equipment. Turn off the power at the disconnect or breaker before removing any panel, keep your hands clear of wiring, and do not touch refrigerant lines or service ports. The measurements above need only the thermometers, not your hands inside the cabinet. If the airflow checks come back clean and the split still sits outside the target for your model, stop and call a licensed technician. Bring the written log with the model and serial numbers, the outdoor temperature, and both readings with their times. A technician can work from numbers in minutes rather than starting from a guess.
Keep the log in the same binder as your equipment records. When paperwork changes hands, whether a parts supplier shifts or a manufacturer is acquired, the readings you took on a calm day stay with your system. They show what the equipment did before anyone else touched it.