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HVAC technicians are responsible for comfortable, clean air. It’s an unwritten expectation in their job descriptions. How technicians achieve this mandate is left up to their interpretation of each heating and cooling situation. There is one component, however, that every installation must have — electricity. This silent force behind a majority of standard living in North America, electricity is a powerful tool when harnessed correctly but a lethal danger when handled improperly. To wield this power correctly, HVAC technicians have a responsibility to gain training and experience.

Electricity in Many Parts

Understanding electrical systems requires HVAC technicians to learn several aspects of electricity, including concepts such as electrical theory, wiring, circuits, and voltage.

ACCA offers a training course to help contractors train their employees on the topic of electricity. In its

“HVAC Training for Technicians: Electricity Basics for the HVAC Technician” online course, a one-hour section covers atoms, currents, flows, and circuits. As part of an overall 6.5 hour course, the first lesson defines electricity relative to atomic structure. The course continues to build on the necessary components and addresses topics like voltage, Ohm’s Law, and safety. It is available to ACCA members and non-members alike, and provides continuing education credits (CEUs) for several licensing and certification entities.

Verified Safety

There are many parts to understanding electricity, but one topic that everyone seems to agree comes first is safety.

TRUST BUT VERIFY: Always check for voltage, no matter who says they turned the power off to the unit or system being serviced.

"Never trust electrical disconnects or panel labels regarding which breaker serves the equipment — always, always test for the presence of power before working within the equipment," said Dave Yates, past president of F.W. Behler Inc. in York, Pennsylvania. "Use lockout tagout safety protection."

Brian McDonald, owner and general manager of One Hour Heating & Air Conditioning in Kill Devil Hills, North Carolina, suggests a trust-but-verify approach to electrical disconnects.

“Always, and I do mean always, check for voltage, no matter who says they turned the power off to the unit or system you’re servicing,” he said. “Even if you think you turned it off or the boss says they turned it off, it’s your life, and you deserve to go home at the end of the day. We’ve all seen service disconnects that have been bypassed internally and look normal from the exterior, but when you turn it off, one side of the circuit or both may stay energized.”

Reading the Lines

As HVAC technicians continue to add to their electrical skillset, reading wiring diagrams becomes a valuable asset for comprehension of system function and in diagnostic troubleshooting.

“The most important electrical skill besides safety that an HVAC technician should have is the ability to read schematics and wiring diagrams,” said Karl Panyko, service manager, Samm’s Heating and Air Conditioning in Plano, Texas. “Even if you have never had experience working on a particular machine, the diagram/schematic can guide you through the troubleshooting process.”

Low voltage troubleshooting and understanding a wiring schematic are the most valuable skills for the technical side of the business, according to McDonald.

A wiring diagram is a line drawing that shows how the electrical connections of a device are made. By going over this diagram and testing each point along the way, HVAC technicians can often find what is wrong with a system that is having an electrical problem.

“Although there are a number of mechanical problems that cause an air conditioning system to fail, the vast majority — over 75 percent — of air conditioning system failures are electrical in nature,” said Eugene Silberstein, director of technical education and standards at HVAC Excellence and lead author of Cengage Learning’s Refrigeration and Air Conditioning Technology textbook. “It is, therefore, essential that field service technicians be able to troubleshoot electrical circuitry and components as effectively and efficiently as possible.”

According to Silberstein, many students who are studying HVAC find the electrical portions of their training to be the most difficult.

“This poses a challenge for them when they complete their programs and enter the workforce,” he said. “Educators are well aware of the gap that often exists between what program completers are capable of doing and what the industry expects in terms of electrical prowess. Great strides have been made over the past 20 years in education to significantly narrow this gap.”

HVAC Excellence provides validation of electrical knowledge and skills at various levels, depending on where HVAC technicians are in their careers.

“We offer complete training packages to help entry-level learners master electrical fundamentals, while offering more advanced certifications for those already working in the field,” said Silberstein. “At HVAC Excellence, it’s not all about whether a test candidate passes or fails an examination. More importantly, we find that identifying an individual’s strengths and weaknesses help create an ongoing learning path for continued improvement.”

Tools Of The Trade

HAVE THE RIGHT TOOLS One of the most popular tools used in electrical applications is the multimeter, a tool used to measure two or more electrical values like volts, amps, and ohms.

Along with safety and the ability to use wire diagrams correctly, another important component in proper electrical work is having the right tools and understanding how to use them. One of the most popular tools used in electrical applications is the multimeter, a tool used to measure two or more electrical values like volts, amps, and ohms. There is a wide array of multimeter prices and models, but technicians are often looking for consistent accuracy from their device of choice.

Chris Barnes is the director of residential service at Reliable Heating in Kennesaw, Georgia. He received his electrical training from a Florida tech school and said that confidence in using electrical tools, like the multimeter, is important.

“Always test your equipment before use,” he explained. To do this, technicians should use a known, functioning circuit to establish a baseline.