Today’s smart residential systems use a lot of those smaller electronics we mentioned last month, to gather a variety of information from around the system. Intelligent devices such as Comfort Alert® Diagnostics use the scroll compressor as a sensor and can send diagnostic information about operational parameters and error codes to and from the thermostat, compressor, the diagnostic component itself, and the rest of the system.

By reading a series of blinking lights or specific alphanumeric codes, and using a guide to interpret those codes, the service technician can trace them back to a specific problem area. It guides him or her to the root cause of the problem.

This is very significant in the residential HVAC service industry. For instance, about 1/3 of compressors are misdiagnosed. Often they are believed to be grounded when, in fact, there is a minor electrical problem in the system, like a bad capacitor.

For a product like Comfort Alert, for example, a yellow alert LED would indicate that there has been a fault code somewhere in the system, such as a high side fault, low side fault, or various electrical faults. A red trip LED indicates that the compressor protector has tripped.

A pass-through port on the unit is able to detect run/start current. Spade connectors detect thermostat demand and pilot voltage. A microprocessor analyzes the system over time, and uses that information to determine specific faults.

Finally, a diagnostic key directs you, the service technician, to the source of the problem.

New developments in residential onboard diagnostics include direct connection to a specific brand of thermostat. You can access those alert codes indoors, though your customers cannot. Future product developments will even allow you to download the system’s alert history to a PC or handheld device.

The system’s diagnostics will help you find the problem more accurately and quickly, but your skills and knowledge are still needed to interpret the codes, take additional diagnostic measurements, and find and fix the problem. Being able to have that operational system check really improves your odds against a callback.

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