Christmas Spirit

This will be a short post. I ran across this listing of organizations that help people in creative ways by redirecting resources we already have and i had to share it. I believe these good people have the right idea. Merry Christmas!

http://www.cnn.com/2010/LIVING/12/23/cnnheroes.12.ways.of.giving/index.html?hpt=C1

The Treasure Hunt

Although this blog normally features articles on air conditioning instruction, I am taking the liberty of writing on the current Christmas Season in this one. It is nearly Christmas and many of us are neck deep in the annual last minute treasure hunt that takes place this time of year. We scour adds and the internet looking for elusive gifting treasure. We sacrifice time, health, and wealth in an effort to secure those must have gifts in our annual treasure hunt. The tension is heightened because we compete against each other; there are only so many baby bobble heads to be found! Even if you are not particularly religious, you probably have heard the famous verse from Luke 12:34 “For where your treasure is, there your heart will be also.” The normal interpretation of this verse is to point out that you invest your time and money in what you really love. I think most people recognize the truth in this statement even if it can make us uncomfortable. However, I would like to turn this around a bit and suggest  that your heart will locate your treasure for you in this mad scramble treasure hunt. What would you miss most in your life if it were suddenly taken away? The answer is probably not something, but someone. Hopefully several someones. Afterall, why are you trying to locate the baby bobble head? To see the look of joy on someone’s face. So in the din of the treasure hunt let your heart guide you to your treasure. My treasure greets me in the morning, sings in the choir, plays in the marching band, and studies at Vanderbilt. I am a wealthy man!

Cool Toys for HVAC/R Instructors!

Document camera? I thought this thing was an air conditioning component magnification system! I have been learning to use my new toys this quarter. I was given a document camera and video projector for my class room. Many people know these things as Elmos because that is who developed the first ones. If you are unfamiliar with them, they are able to zoom into a document placed on them so that you can project it to a screen using a video projector. That is OK, but what I use it for is projecting images of components and tools. Put a defrost board on it, zoom into the defrost setting jumpers, and show how to set the time on an electronic time-temperature defrost board. Look at the color bands on resistors. Ohm the coil out on a relay and show the meter as you ohm the coil out. Wire a simple circuit and operate it, then measure the voltage drop across the switch. Disassemble a TEV and show the difference between an internal and external TEV. Show the difference between the wire gauge of the run and start winding on a split phase motor. I am just getting started, but I think you get the drift. You can show detail in real time and everyone can see and follow what you are doing even better than if they were standing beside you. Having drawn many extemporaneous works of art on the white board, I still sometimes revert to my older chalk and talk methodology. Elmo helps there as well. If I really feel the need to scribble, I can draw on a piece of paper and project the drawing. If the scale is not quite right, the zoom lets me show it off to full advantage and I don’t have to clean the white board afterwards. I have an internet connected computer in the podium as well. The video projector works great for showing MyHVACLab on the screen. When we discuss the questions at the end of the units, I project the e-book from MyHVACLab. Then I can show relevant information from the book as we review the unit and the students can follow along in their textbooks. I use the mouse to point out any particular coverage in the book I want to highlight. Of course the video projector also works for showing powerpoint presentations and video clips, but I have not shown any videos yet because I am too busy showing all the cool HVAC/R parts. I have a large collection all around my podium of things I have confiscated from the lab, including a few unit panels. If someone asks a question about a part I don’t have I am likely to find one by the next class. I got the idea I wanted to show the phase shifts caused by inductive reactance and capacitive reactance. The electronics department loaned me a digital dual trace oscilloscope that is small enugh to fit on the Elmo. I am going to build a circuit to show phase shift on the oscilloscope. I know lots of text books have drawings of this, but I don’t think many students pay a lot of attention to them. I am hoping when they see the shift occur right in front of them on the big screen in real time the information will sink in. At the very least, I know that I will have a good time playing with my new toys. I hope my students will see how cool this all is and want to play too.   

A Few Quick Service Tips

Technicians often feel pressure to work quickly. Many technicians have quotas- either the number of calls per day or revenue dollars per day. Even without an explicit quota, everyone works on a quota. You have to make money for your company or they cannot afford to employ you. If you are working for yourself, you have to make money to pay your bills. It can be difficult to put this out of our mind when we are working. There are some tricks you can use to maximize your productivity that are helpful, and there are some shortcuts that can get you in trouble. I believe that you save time overall by not skipping steps, but you can arrange your work flow to avoid wasted time. First, take the time to talk to the customer to find out what the complaint is and ask questions. Often, symptoms that the customer has noticed may give you some clues. Next, I always want to see the thermostat to verify that it is set correctly and calling for the system to operate. There are a significant number of customers that do not know how to operate their systems, especially with today’s programmable touchscreen digital thermostats. If the indoor blower is not running, set the fan switch to “On” to see if it comes on. If it does you know that the indoor unit has power, the transformer is providing control voltage, and of course that the fan and its control are working. If the fan does not come on, you have a good idea of where to start checking. Always do the easy stuff first. This is not just being lazy, it is being time efficient. It is never wrong to check the air filter; that should be done on each call anyway. If the filter is blocked you are wasting your time trying to adjust the charge. More often than not, the problem is a relatively simple issue. While you are changing the filter, take a look at the vent if the system is a gas or oil furnace. I have found vents rusted through while under a house checking a stopped drain in the summer. If you are the last HVAC/R technician at someone’s house, you have a responsibility for the safety of the system. For more ideas on efficient troubleshooting, check out Unit 86 Troubleshootng in Fundamentals of HVAC/R.

New R22 Units Coming!

The drama over the R-22 phasedown has been something of a soap opera. Just when you had adjusted to the fact that they killed off your favorite character, voila, they are raised from the dead! Manufacture of new equipment charged with R-22 stopped January 1, 2010. However, Carrier, Goodman, Lennox, Nordyne and Rheem are reported to be planning the production of dry R-22 condensing units for the replacement market.  How is this legal? Well, these are for replacement, not new installation. And,. they are not charged with R-22 - at least not by the manufacturer. A dry unit is one that is evacuated and charged with dry nitrogen, not refrigerant. The units can be used to replace existing R-22 units and then charged in the field. The replacement installer needs to purge the nitrogen charge, evacuate the entire system instead of just the lines and coil, and then charge the system with R-22 according to factory recommendations. Alternatively, environmentally conscious contractors could opt for a non-ozone depleting R-22 replacement. Check out Fundamentals of HVAC/R for more specifics on how to properly install an air conditioning system.

These dry R-22 units would give customers an option other than replacing their entire system with a new high priced 410A system. In today's economy customers often simply cannot afford to purchase a complete R410A system. They are left with a few bad options. Do without, or put money into repairing an aging, inefficient piece of equipment that really should be replaced. 

There are many questions to be answered, such as efficiency certification and avoiding potential legal landmines with the EPA. In some people’s minds it is not a good idea because they don’t believe today’s technicians properly evacuate the lines and coil on current systems. If these same folks charge an entire system without evacuating it, the head pressure would be so high that the system would likely not run long, if at all. This might be a blessing in disguise. If every unit they put in refuses to work, at some point even the most obstinate slacker would have to suspect that they are not doing it right. Success will depend more than ever on using skilled technicians that have the proper training. For more specifics, read the article on the Heating Air Conditioning and Refrigeration News website. R-22 has remained readily av available and the price has not spiked as much as had been predicted. Both of those situations may change if several major manufacturers start selling new products that require R-22 refrigerant. There are several R-22 work a likes now, but you had better check with the manufacturer before charging a new product with one of them. The equipment UL rating and manufacturer's warranty could possibly be voided by using an alternate refrigerant. For older equipment whose warranty has already expired, that is not too much of an issue. But for new equipment that still has a warranty, losing the the warranty would be a problem. Right now getting their efficiency certified is an issue. Air conditioners cannot be sold until they are certified to meet the minimum SEER rating. AHRI removed all their R-22 listing, thinking we were done with new R-22 systems. Stay tuned - it is bound to be interesting! 

Count Your Blessings

Last year I posted a thanksgiving article citing reasons for folks in HVAC/R to be thankful, myself in particular. If you are teaching HVAC/R, I know that you are experiencing record record enrollment at a time when your financial resources are dwindling. Although your job is difficult, you do have a job. A very important one at that. Your classes are filled with good men and women who do not have a job and they are looking to you for help. Both the economic situation and my reasons for being thankful in the face of adversity remain the same, so I am reposting last year's comments. 

At thanksgiving we should all take time to reflect on our blessings. For me this has been a great year filled with an abundance of blessings for which I am truly thankful. Unfortunately, many of my students have had setbacks in their life the past couple of years. I suspect many of your students have as well. We are seeing a wave of students who are preparing for a second or third career because their previous career was abruptly terminated. The plant they worked for closed, the building contractor they worked for has no projects, or the company they worked for has gone out of business. These are good people whose life has been turned upside down. It would be easy for them to concentrate on the past and what they have lost rather than what lies ahead. Dwelling on past misfortunes can be harmful to your health, adversely affect your present and threaten your future. I believe that one of the most important things we can do for these students is to keep them focused on their future. I have seen economic downturns and displaced workers before and I know the end game. These folks will merge their current skills, knowledge and experience with the knowledge and skills they will learn in their HVAC/R program to quickly become leaders in their new field. HVAC/R needs them.

Here is a list of a few things today’s air conditioning students can be thankful for.

• The need for heating, cooling, and refrigeration systems is only going to increase.
• They are starting a new career in a field that desperately needs skilled workers.
• There are still openings for skilled air conditioning technicians even during this economic downturn.
• Installation and repair of HVAC/R systems cannot be outsourced to foreign country.
• The wages earned will remain competitive because the work cannot be done by unskilled workers.
• They will enter the field with training for new refrigerants at a time when this knowledge is crucial.
• They will enter the field with training for new high efficiency systems at a crucial time as well.
• They are entering a field that is consciously increasing the level of professionalism and certification.
• They have experienced HVAC/R educators to help them make this career change.

I wish for all of you an abundance of blessings for the coming year.

CO Scare

I think that warnings about common hazards can become so commonplace that we don’t pay enough attention to them. We need something to wake us up. This week I received a wake up call when one of my students showed up to class explaining that his entire family had been suffering from carbon monoxide poisoning. He had missed over a week of classes and had come by once to explain that everyone at his house was sick. His family physician suspected something was up after treating everyone in the family for symptoms that mimicked flu. The doctor confirmed that they were indeed all suffering from CO poisoning. A little investigation revealed that the vent for the furnace in the attic had never been connected. There was a vent pipe, but it ran to within a foot of the horizontal furnace and stopped. The furnace was changed when he purchased the house. He showed pictures of the furnace. It was a model that can be difficult to connect vent to because the vent comes through the front access panel. I imagine the installers did not have the right parts, left it for “later” and forgot about it. The HVAC/R contractor did not get a permit, so there was no county inspector to find the problem. The home inspector did not catch it, from the attic access the vent looks like it is connected. The student thought that he had combination smoke and CO alarms. Turns out, they were just smoke alarms. So an obvious safety hazard that is easily corrected went unnoticed until the weather turned cold. The good news is that nobody died, the house now has CO alarms, and the source of the problem was found and corrected. It is scary to think what the end result could have been if the problem had not been recognized or if the weather had stayed cold for a longer period of time.

More people are sickened or killed by carbon monoxide poisoning than any other type of poison. The Center for Disease Control and Prevention (CDC) reports that each year more than 500 people in the United States accidentally die from carbon monoxide.  An estimated 10,000 people in the U.S. are treated for CO poisoning in hospital emergency rooms annually.  It is believed that many more people suffering CO poisoning are misdiagnosed, or never seek medical care. This is because the symptoms of CO poisoning are very similar to influenza symptoms. One big difference is that influenza causes a fever and CO poisoning does not.

Carbon monoxide is an odorless, colorless gas that is highly poisonous. It is formed by the incomplete combustion of carbon based fuels, like natural gas, oil, coal, or wood.  Incomplete combustion can be caused by lack of oxygen, improper mixing of the fuel and oxygen, or too low a combustion temperature. A correctly adjusted gas or fuel oil flame should produce very low levels of CO. Ideally a correctly adjusted gas or oil flame should produce no CO, but realistically, most produce at least trace amounts. Solid fuels almost always produce large amounts of CO; that is why charcoal comes with a warning that it is not to be used inside.

HVAC/R technicians are in a position to help. We can make sure all combustion appliances in the home are burning correctly, insure there is enough combustion air for proper combustion and venting, and finally by making sure the vent system is adequate and working correctly.  For gas and oil furnaces also remember to inspect the heat exchanger for leaks. The heat exchanger separates the combustion products from the air circulating in the home. Although a defective or cracked heat exchanger can contribute to CO poisoning, more obvious problems are frequently to blame. Stopped vents, loose or leaky vents, and lack of combustion air are common causes of CO. While every technician should learn to look for conditions that can lead to problems, testing is required to verify that a system is operating at safe levels of CO and that there is no CO in the house. Every technician should have an accurate CO tester. Household alarms are not a substitute. While every house with gas or oil appliances certainly should have CO alarms, they are not a replacement for an accurate tool for diagnosis.  I highly recommend a seminar done by Bob Dwyer for COSA (Carbon Monoxide Safety Organization) Make sure and take advantage of the opportunity if you have a chance to attend one of his CO Safety Seminars.

There are many units in Fundamentals of HVAC/R to help explain how to achieve safe, efficient combustion for gas and oil furnaces, including

Unit 37 Gas Fired Heating Systems

Unit 38 Warm Air Furnaces

Unit 40 Gas Furnace Installation, Startup, Checkout, and Operation

Unit 41 Troubleshooting Gas Furnaces

Unit 42 Oil Fired Heating Systems

Unit 43 Oil Furnace and Boiler Service

Unit 44 Residential Oil Heating Installation

Unit 45 Troubleshooting Oil Heating Systems

There are many good web sites for more research on carbon monoxide poisoning. A few are listed below.

http://www.bbc.co.uk/health/conditions/carbonmonoxide1.shtml

http://www.cosafety.org

Speed Up Your Service Calls

HVAC/R Technicians are under a lot of pressure to work quickly. The customer wants the problem fixed now. In the customer’s mind, the problem is fixed when the technician answers the door. If it were only that easy! The company also wants the technician to work quickly because time is money. The technician’s significant other wants the technician to work quickly and get home on time. Today people are so accustomed to downloading what they want, when they want it that they expect everything to come as easily and quickly. Life conspires to pressure the technician to repair HVAC/R equipment in the time it takes to download a movie. About the only way to actually accomplish this type of blitzkrieg service is to jump to conclusions and get lucky. It can you look brilliant to go right to the offending part on a hunch, replace it, and have the unit operating in minutes. But you can also look foolish if the unit quits operating before you get back to the shop. The customer now loses confidence in your ability. They can also feel cheated, suspecting that you did not check out the system thoroughly because you were there such a short time. From a practical standpoint, you have not saved any time if you have to return. In fact, your quickness has cost you time. I believe that being careful saves time in the long run and builds your reputation as well. Here are a few ideas on real time savings. Before you go to the service call, you should

Study! Your knowledge is the most powerful weapon in your troubleshooting arsenal. Read texts such as Fundamentals of HVAC/R, subscribe to service magazines such as the RSES Journal, enroll in classes at your local Technical College, join the local RSES chapter, and attend manufacturer’s service seminars. There are so many excellent educational opportunities for the HVAC/R industry that there really is no excuse to remain ignorant. Each hour you spend learning about your trade will save you many hours later on.

Build a good service library. You can’t keep an entire HVAC/R service library on your truck, but you can keep a few of your favorites. Don’t sell your HVAC/R tests – you can use them in the field. Service manuals and bulletins from equipment manufacturers are also very handy. If you can afford it, get a laptop with wifi internet. Most Companies now keep very complete service information on their web sites. 

Invest in quality tools. It always takes longer to do the job without the right tools. Don’t skimp on tools! Good quality tools that are made to perform the specific task at hand save you time. You can sometimes bang a motor shaft out of a blower wheel with a hammer and wood block, but it is so much faster and easier with a hub puller. And you will really cost yourself a lot of agravatino and time if you mushroom the shaft or warp the blower wheel.  

Next week I will discuss some tricks to speeding up the call after you arrive on the job.

Are Your Capacitors Stale?

A capacitor is a pretty simple device, basically a couple of rolled up sheets of aluminum foil or metalized film with paper or plastic between them. Any practicing service tech will tell you that service calls involving dead capacitors  are common. Technicians that have been around for a few decades will also tell you that capacitors die a lot more now than they did twenty years ago. This is because the newer capacitors use a different electrolyte. The electrolyte in the “good old style” capacitors was polychlorinated biphenyl, PCB. PCB causes cancer, so it is no longer used. The newer capacitors are smaller and less expensive than the older PCB capacitors, but they are not as robust. The two most common causes of capacitor death are heat and over voltage. However, there is another less known cause: old age. Many capacitors have a shelf life. I have seen shelf lives listed as little as one year. The oxides on the metalized film break down when the capacitor is not in use, weakening the capacitor. They tend to self-heal during use. That is why a capacitor that cannot sit on the shelf for longer than a couple of years can last for ten years in use. 

Always check the capacitance of any replacement capacitor with a capacitor tester or the capacitance scale on a digital multi-meter before using the capacitor. It may have already died of old age before you install it! Although a capacitor is a simple device, it is an extremely important part on most air conditioning systems. A bad capacitor can kill a system’s compressor. To protect your reputation and your customer’s equipment, only use capacitors that can pass the EIA-456 Highly Accelerated Life Test. The HALT test subjects a set of capacitors to 125 percent of their rated voltage and 10˚C above their rated temperature for 2,000 hours. For example, a capacitor that is rated at 5uf/440 vac, with an operating temperature of 70˚C, is tested at 550 vac and 80˚C for 2,000 hours. Two links for more detailed information on capacitors are  

Aerovox

Genteq

Determining which capacitors to stock on your truck is another problem. There are so many sizes of dual capacitors that it is nearly impossible to have all the necessary sizes. American Radionic, AMRAD, has a solution – a multiple capacitor with enough sizes to cover nearly any application. Better yet, they will send instructors sample capacitors to use in your lab. These are great for demonstrating the effect of connecting capacitors in series and parallel. Their web site is AMRAD

Fundamentals of HVAC/R has coverage of capacitors and their effect in circuits in  Unit 29 Electrical Power and Circuits, Unit 30 Electric Motors, Unit 33 Control Circuits, and Unit 83 Troubleshooting Refrigeration Systems. Unit 30 of MyHVACLAB has an interactive exercise on determining capacitance and a video on testing capacitors. Unit 83 has an interactive exercise on testing capacitors. 

Simplify Parallel Calculations

The total resistance in a parallel circuit is difficult to calculate because it cannot simply be added as in a series circuit. However, the total current flow in a parallel circuit is easy to calculate. It is simply the sum of the currents for all the individual loads. The famous parallel formula for resistances in parallel uses this concept.  Dividing the resistance of each load into 1 calculates the current draw for each load at 1 volt. Adding these fractions gives the total current draw of the entire circuit at 1 volt. Since resistance can be calculated by dividing current into voltage, dividing the total circuit current at 1 volt into 1 volt gives the total resistance. I confess that I have used and taught this formula for many years without knowing why it works. Once I understood the reason behind the formula, it seemed far more logical and less imposing.  Did you know that this works for any voltage you choose? We can use this to create a simpler parallel calculation. 


I find that many of today’s digital students struggle with the fractions, common denominators, and all the trappings that go with fractions. One solution is to convert the fractions to decimals. But the decimal numbers you get when dividing whole numbers into one are always several decimal places to the right of 0, causing another own sort of confusion. My suggestion is to choose a voltage at least equal to the highest resistance; preferably, twice the highest resistance. That way, all the answers will have at least one whole number. This not only makes the answers easier for the students to deal with, it makes the decimals to the right of 0 less significant, so lopping off a few won’t have as big an impact on the final answer.


 For example, with resistances of 15, 20, and 30 ohms choose 60 volts. Instead of trying to add 1/15  + 1/20 + 1/30  or their decimal equivalents, you are adding 60/30 + 60/20 + 60/15. Most people can add 2 + 3 + 4. Then, divide this total current, 9 amps, into the voltage we used, 60 volts, to get 6.6 ohms total resistance. OK, so I stacked the deck a bit. Another teacher’s trick – if you get to choose the questions, why not choose questions that make your life easier. After your students are adept at these “easy” problems, have them measure the resistance of some actual devices and do the calculations. This is where choosing to make the calculations easier really pays off. Anybody can make simple things difficult – the trick to teaching is to make difficult things simple. 

A Story of Personal Courage

Have you ever wondered how you would react in the face of personal tragedy? I have. When I read about tragedies in the paper or hear about them on the news, I find myself wondering “What if..?”  Fortunately, I have never found out. Soon the business of the day drowns out my musings, and I return to the business at hand. However, the closer to home the tragedy is, the more difficult it is to dismiss. 

Just before the start of this past summer quarter, my friend Bruce Arnold lost his 18 year old son Tyler in a motorcycle accident. Tyler was preparing to study air conditioning at Athens Tech and study with his dad. Bruce works in the field and takes classes in the evening. Bruce was so excited about his son going to school to study the trade he practices.

Only a parent can truly understand the feelings parents have for their children. You really cannot fathom how much you have been loved or how much of themselves your parents invest in you until you are a parent. When you are a teenager your parents unending questions about where you are going, what you are doing, and who you are going to be with are an incredible annoyance. Their interest in every detail of your mundane school day is perplexing. The reason is simple: parents have more interest in your safety and success than you do.  

Nobody celebrates your victories and accomplishments more than your parents. I have been teaching longer than most of my students have been alive, and I know that my mother is still my biggest booster. I have a 20 year old daughter and a 15 year old son, and I know I get far more excited about their accomplishments than my own. That is why I know there can be no greater pain than losing a child. Truthfully, I hope I never learn what it feels like.  

Bruce returned to school and completed his summer coursework. He explained that he felt compelled to come back to school because Tyler was so proud of his dad for going to college and so happy to be going himself. Many of Bruce’s friends counseled him to “put it behind him” and “go on with his life.” He couldn’t. Instead, he started a non-profit scholarship foundation in his son’s memory. He hired a lawyer to create the non-profit foundation, established a bank account for the foundation, started a web page to advertise his foundation, and is out personally raising money for the foundation. His goal is to raise money so other young men and women can realize their future, fulfilling their parent’s dreams. If you would like to learn more about Tyler or the scholarship foundation established in his name, go to http://www.thetylerbrucearnoldscholarshipfund.com/index.html   

Where Do YOU Belong?

You can tell a lot about someone by looking at who they hang with. The people and organizations you spend time with help form who you are and advertise to the world what you really think is important. I believe finding where you fit in is important. You may have heard people talk about networking: not a connection between machines, but a connection between people. Spending time with people that have similar interests and developing your common interests. Some of the benefits are obvious, like making valuable connections to folks that can help you. However, I believe part of the power of networking is that you find a group of people whom you enjoy being with. The truth is that most people are more inclined to put effort towards helping someone they know and like. Being with other people who share your interests makes all your activities more meaningful. Disneyworld is no fun by yourself; a big part of the magic in the magic kingdom comes from having fun with your family.

Joining an industry organization gives you immediate access to a group of people with similar interests. There are many groups organized around different aspects of the HVAC/R industry. There is a group for HVAC/R Technicians – RSES; a group for trades students – Skills USA; a group for Air Conditioning Contractors – ACCA; a group for HVAC/R Distributors – HARDI. If you teach HVAC/R you have some common interests with all of these groups. Every one supports HVAC/R education with resources and material. Trying to participate in all of these would probably not be possible for most of us, but joining and participating in one is doable for even the busiest folks. I suggest exploring what all of these groups have to offer, finding where you belong, and taking the plunge.

Each organization has an annual meeting where you can network with other HVAC/R folks, participate in training, see the latest in HVAC/R technology, and just have fun. If you have never been to a national HVAC/R convention, an opportunity coming up would be the National RSES Conference in Tucson, Arizona November 9 – 13.

Here is a partial list of HVAC/R organizations with links to their web sites where you can learn more about each one.

ACCA – Air Conditioning Contractors of America

ACTE – Association for Career and Technical Education

AHRI – Air Conditioning, Heating, and Refrigeration Institute

HARDI – Heating, Air Conditioning, and Refrigeration Distributors International

HRAI – Heating, Refrigeration, and Air Conditioning Institute

HVAC Excellence - Heating, Venitlating, and Air Conditioning Excellence

NAOHSM – National Association of Oil Heating Service Managers

PHCC – Plumbing, Heating and Cooling Council

RSES – Refrigeration Service Engineer’s Society

Skills USA

Understanding Relationships is Key

During the quiet times between quarters, our team members will often discuss what students are struggling with, what WE are struggling with, and look for ways to address these issues. The other day we were discussing why many students have such a difficult time learning how to identify the common, start, and run terminals on compressors. A few other problem areas came up – reading diagrams, superheat, subcooling, and system charge compared to superheat and subcooling. Then it struck me what all these things had in common – they are all relationships. You have to compare two or more pieces of information to arrive at a solution. Over my years of teaching, I have noticed that the more abstract a concept is, the more students struggle with it. Identifying components is usually not a problem because that is very concrete, just putting a name with something you can see and touch. Memorizing definitions is also fairly straightforward, even if it is not very exciting. Most students can give us a pretty good definition of superheat. But we lose many of them when they have to actually measure it on a unit. We lose even more when they have to use that measurement, compare it to the manufacturer’s specification, and determine if the charge is correct. I believe if you made a list of all the most important things students should learn to do before they leave you would find the most important skills involve understanding relationships. I don’t know of a sure fire way to teach relationships. I think that people who have a good mechanical aptitude readily see relationships. Students that have difficulty understanding relationships need explicit instructions and lots of practice. Teaching something that is “obvious” to you can be difficult because you have to deconstruct your thinking process so you can explain how you accomplish a task that you do innately. For example, suppose you had to teach someone how to use a screwdriver. Do you know exactly how you hold it? How do you get the screw started? What do you do after turning your wrist a quarter turn so that you can turn the screw some more? I have actually had to teach people how to use a screwdriver and it was one of the most difficult things I have ever taught because I really did not know how to explain it. Admittedly, the screwdriver example is extreme. However, the same type of deconstruction process can be used to explain more analytical processes like measuring superheat. My prescription for helping relationship challenged students is to:

Analyze the task in detail – leave nothing out and assume nothing.

Teach the students the process in explicit detail making sure they understand each step.

Practice, practice, practice!

Patience, patience, patience!

Remember, if all the students could do everything easily on their own they wouldn’t need you.

Are You Practicing for Success or Failure?

We are what we repeatedly do. Excellence, then, is not an act but a habit." – Aristotle

I would like to propose a slight revision to Aristotle’s line of thought: Success is not a condition, but a habit. Have you ever known someone that is lucky and seems to go from one success to another? It is sometimes difficult not to be envious of their success and wish we were so lucky. If the primary action you take towards becoming successful is to wish for success, chances are you will not find it. People are not successful because they are lucky; they are successful because they prepare for their success through repetitive practice. So the question is: “Are you practicing for success or failure?” You might ask “Who would practice for failure?” However, I have seen many students diligently practicing for their inevitable failure. They practice for failure by not preparing for class, arriving late, and making endlessly creative excuses for their failure to succeed. Eventually they become expert at failing – eliminating all chances of success. I will not tell you that if you work hard and put your best effort into everything you do that you will always be successful. But I can guarantee that if you do not work at being successful, you will fail. So you can take the sure thing – guaranteed failure, or you can put yourself out there and risk being successful.

The Strength Remains

Nine years ago, I was working in my office at school when a teacher from down the hall came in and said that a plane had flown into one of the World Trade Center Towers. While I was searching for information about the first plane, the second plane hit the other tower. It was only then that I realized we were under attack. I believe the trade center towers were chosen because they became an icon of American strength. Rather than weaken us, the attacks strengthened us in many ways. We proved our mettle immediately following the tragedy. Stories abound about how people rose to the challenge: from police and firemen risking their lives to politicians speaking with one voice as Americans. My favorite story involves St.Paul’s Chapel directly across the street. Somehow St. Paul's survived the shower of debris and was transformed into a round the clock hostel, providing care and support for eight months to the rescue and recovery workers. Volunteers came from all over America to work there. So many volunteers came that they had to be scheduled and their time helping was limited to allow everyone a chance to experience the blessing of helping. People cried when their time was up and they had to leave.

The towers came down. The strength remains.

Are You Giving Your Students Cognitive Indigestion?

One cold wintry Friday, the philosophy professor at a small college looked out at his class only to see a single student. The snow was deep, the wind was blowing, and the rest of the class just was not able to make the long, cold trek to school. Undaunted, the professor launched into the full text of the lecture he had prepared. He was determined to reward the student for his faithfulness and deliver his best lecture ever. He elaborated on each point. He quoted from multiple sources, contrasting their different approaches to the core argument. He gave stirring testimony about the marvelous accomplishments of visionaries who had followed the tenets of the philosophy he espoused. And finally, he concluded with a call to his audience, exhorting him to embrace the difficult but rewarding path he had just laid out. After speaking passionately for two hours straight, the professor was so excited he could not wait to ask the student his impression of the lecture. The student was quiet for a long time before he spoke. “Professor, I have to feed the cattle at my folks this afternoon. If there is only one steer in the barn, I’m not going to make him eat the whole bale of hay.”

I have sometimes been guilty of trying to feed my students the whole bale at once, trying to include every excruciating detail about a topic before they have gained a broad understanding. Information overload can cause cognitive indigestion. This occurs when the listener has a large amount of data without any real framework to organize and understand it. Most people tend to learn in stages, unfolding a little bit of the mystery at a time. The study of electricity is like this. We start with general description and then add ohm’s law to refine the idea. Then after the students have the hang of standard ohm’s law formulas, we add series and parallel calculations. After students can handle these we tell them that ohm’s law is not valid for most air conditioning work because of inductive and capacitive reactance. If you are really sadistic, you will then trot out the LCR calculations. There is method in our madness. If we were to drop all this on the students in the first week, most would become confused and frustrated. It is OK to leave out details and fill them in as the students gain subject maturity. In fact, for most folks it is preferable. It is far better to feel that you are making progress, than to feel that you are drowning in information. One of the ways that I know when a student is really “getting it” is when they comment that they are beginning to understand how much they don’t know. Typically, these are some of the brightest students – they are gaining enough insight to get a glimpse of the bigger picture. It is all right to try to teach your students everything you know. In fact, your goal should be for your students to learn more than you know. It just will not happen overnight. If you guide them well, it will happen and they will return to share their knowledge and success with you. There is nothing more rewarding.

Service IS What We Sell

HVAC/R service technicians must master many different skills to be successful. There are the hard skills that involve manipulation and mechanical ability like electrical wiring, brazing, and refrigerant handling; there are the problem solving skills like refrigeration and electrical troubleshooting; and there are soft skills such as customer service. Service technicians must be competent in every one of these skillsets. Note that these skillsets are quite different from each other. The hard skills require mechanical ability and a good kinesthetic sense. Problem solving requires abstract thinking and the ability to take several pieces of information and form a reasonable judgment. Even if a service technician has great mechanical ability and is an accomplished problem solver, they must be able to deal with customers. Service work is primarily about customer service. Often, individuals who are mechanically gifted are not “people persons.” They would much rather rebuild a compressor than talk to the compressor’s owner. The problem is that the compressor is not who writes the checks, the owner is. So if you want to be paid, you need to learn to talk to the customers.

Increasingly, service technicians are required to make out a bill and collect payment. I consider this yet another skill set – financial. In the good old days, I would simply tell the customer that they would receive a bill. When they wanted to know how much it would be I honestly did not have a clue. I might as well have told them to write a check and leave the amount blank so I could fill it in for their convenience later on. Customers now expect to know what they owe before the technician leaves. In many cases, the company expects the technician to collect payment. To create bills and collect payment technicians must be familiar with the company’s pricing policies. Many companies use price books which list prices for specific services. The price includes all aspects of the cost - parts, labor, overhead, and profit . Technicians bill customers according to the services they deliver. The technician needs to learn how the book is organized and be comfortable looking up prices in the book. Many technicians are uncomfortable using the books, making bills, and collecting payment. Often, companies just hand the new technician the book without much training. Although every company’s price book and billing procedure are unique, most companies now require their service technicians to produce bills and collect payment.

I think every HVAC/R program should have some example pricing procedures available to their students. The point is not to tell them what to charge, but to help them prepare to make bills using pricing policies that are prevalent in your area. A vendor for a price book that is used by several contractors in our area supplied us with a sample book. The prices do not reflect any particular company and all services are not in the book. Further, SAMPLE is written prominently across every page. But this book lets us inject a dose of reality into troubleshooting. Students should not only be able to track down the cause of the problem, they should also be able to find the service required to repair the system in the price book.

One thing that many students have a hard time with is the large price discrepancy between the cost of the part being replaced and the cost of providing the service. I emphasize that the customer pays far more for the technician’s expertise and service than they do for the part. The cost of the part is almost negligible. I point out that this is true for nearly any service business. Otherwise, the company cannot make money and their technicians cannot earn a good living. They are not cheating the customer by charging a high price. They are cheating the customer if they fail to deliver complete and competent service. We are called service technicians for a reason.

Making the Connection with Schematic Diagrams

Many of topics that our students struggle with the most have some level of abstraction. Reading a schematic diagram is near the top of the list. A schematic diagram is a symbolic representation of an abstraction – circuit logic. Mentally tying this symbolic representation to the physical components and wires can be a struggle for some students. This is especially true for devices like contactors and relays that are represented by multiple symbols because they have parts with different functions located in different circuits. Recently I have tried having students draw a schematic diagram of a basic packaged air conditioning system. Then I give them a pictorial diagram with drawings of components and ask them to “wire up” their schematic. Most students have a few difficulties drawing the schematic, but they usually make it past this part without too many scuff marks. The trouble comes when they have to translate the schematic diagram that they drew into “wires” on the pictorial diagram. I believe this is because students can essentially copy circuits they see in the book without understanding the details. However, details are important. Several years ago, we would put all our electrical theory up front. Students did not do any wiring until after covering all the theory. However, I noticed that many students who could draw a basic heat pump schematic diagram could not wire a toggle switch and a light. This caused me to wonder how much they really understood. Having students “wire” units on paper by drawing lines between pictures or drawings of components allows them to work out the connection between the abstract and the physical without burning up all your transformers. I am not suggesting that drawing lines to represent wires replaces wiring actual components, but it will quickly show you who has a clue and who doesn’t. You need to work some more with the folks who can’t differentiate between low voltage and line voltage circuits, or the people who want to put L1 on one side of a spst switch and L2 on the other side of the same switch. The pictorial diagrams with all the wires drawn in can look a bit messy and hard to follow. Using color coded markers helps. Better yet, use colored pencils that can be erased. Use two colors for line voltage and two more for low voltage. Have them draw in large dots where two wires are supposed to connect and little humps where two wires cross that are not supposed to connect. It does not take students long to figure out that neatness is its own reward. Loopy, hastily scribbled lines make for difficult circuit tracing and lead to confusion. I usually have a big stack of pages with the components that need to be “wired up.”

Your Job is NOT to Answer E-mail

My job would be so much easier without the constant interruption from these students! It can be easy to lose your focus in the hustle and bustle of running an HVAC/R program. With the demands of documenting things like student learning outcomes, justifying the need for an expendables budget for items like copper, advising students, scheduling classes, attending faculty meetings, and answering e-mail, it sometimes seems like taking care of administrative details is your primary job. There can be a bit of a let-down when the fury momentarily subsides and there are no URGENT e-mails to answer. "Oh there are no e-mails, what do I do?” Then a student comes in, asks a question and I remember why I am there in the first place. It is important that we remember to save enough time and energy to focus on the students. All the other things are just supporting roles, not the main job. One way to keep the administrative part of teaching from completely taking over your time is to set aside a specific time for accomplishing administrative duties. One day a week I do not lecture or teach in the lab, I administer. That way I am not stealing time from the students, trying to complete reports five minutes at a time in between working with students. When you are juggling administrative functions and students at the same time it may feel like you are being productive because you are so busy, but an honest assessment of what you have accomplished afterwards can be deflating. I personally find that trying to juggle students and administrative details at the same time leads to lack of focus and poor performance on both tasks. That is not to say I don’t answer any e-mails until Friday, it just means that I know I have time to accomplish time consuming tasks on Friday. Another trick is to automate administrative tasks whenever possible. I confess that for many years I really could not understand why many of my friends liked using test banks to write quizzes and tests. I was a purist – writing all my tests from scratch so no two tests were ever the same. I would often save them in Word format, and use old tests as templates, but that was the extent of my automation. Then I became involved in writing Fundamentals of HVAC/R and everything that goes with it, including writing a bank of test questions for use with TestGen. It did not take long for me to see the advantage of using an organized test bank. I can write a good test in about five minutes by just selecting questions from the test bank. I can still write all the new questions I want, but saving them in the test-bank format means that I can retrieve them easily later on. With all the Word documents, I end up searching through lots of electronic documents looking for that gas furnace test I wrote last year. Finally, you should learn to use your tools. You expect your students to learn how to use gauges and electric meters. They have to become proficient in their use to do the job they are training to do. Similarly, all instructors should be proficient with office productivity applications like Word and Excel. If Microsoft is not your cup of tea, substitute whatever word processor and spreadsheet program you like, but mastering the word processor and spreadsheet will make your life much easier. I would certainly not try to pass myself off as an expert in either, but I do use both Word and Excel on a daily basis. Since I use them every day, learning to use them well saves me time. This requires an up-front investment of time, but it pays off almost every day.

Communicating Control Systems

The standard air conditioning control system uses relay logic or an electronic representation of relay logic. Things are either off or on. The controls work something like a light switch – when the switch is on the light operates, when it is off the light is off. Thermostats are basically switches that are controlled by temperature. The thermostat closes a set of contacts to complete a circuit to a relay coil, the relay coil then closes the relay contacts to complete a circuit to a motor. When the thermostat is satisfied its contacts open, breaking the circuit to the relay coil. The relay opens its contacts, breaking the circuit to the motor. Everything works based on the presence or absence of control voltage. One advantage of this system is that it is easy to understand, and it has been the basis for HVAC/R controls for many years. However, this control system needs a separate control wire for each function. Some split system heat pumps require 12 control wires running between the indoor and outdoor section. Even with twelve wires, the range of control is still somewhat limited.

A communicating control system is more like a computer network. The system components communicate over a serial network. Each part has its own unique electronic signature or address, allowing the controller to recognize all the parts and coordinate their operation. Most residential communicating systems use four wires between all components – two for power and two for communication. It does not matter if the component is a furnace, air handler, air conditioner, heat pump, or zone control – everything uses the same four wire connection. This works because the units respond to commands sent over the communication network, not the presence or absence of control voltage. Commands for different components can be sent over the same network. Further, communication is not just one way. Communication between components allows them to know what the other components are doing and adjust accordingly. For example, Carrier’s Infinity zone control knows what the blower CFM is and what the CFM in each zone is. Better yet, it can report this to the service technician. The system airflow can be ramped up or down to match system capacity. Staged furnaces, air conditioners, and heat pumps give the system the ability to modulate system capacity and airflow as the house load requires, improving efficiency and reducing energy use. Just a few years ago Carrier was the only game in town if you wanted a residential communicating system. Some folks were not paying too much attention because these systems were only offered in high end equipment made by one equipment manufacturer. Today it seems like everyone is offering a communicating system. Equipment manufacturers advertising communicating systems now include Carrier, Bryant, Trane, American Standard, Lennox, York, Rheem, Ruud, Amana, and Goodman. I apologize in advance for leaving anyone off. The point is that communicating controls are booming. Communicating systems used to be proprietary, now there is an open standard called ClimateTalk. The ClimateTalk will encourage the development of equipment that plays nice across different brands. I don’t believe we are at the point of interoperability yet, but that day is coming. Besides the proprietary systems built exclusively for a particular brand, two major control manufacturers are producing communicating systems – Emerson and Johnson Controls. The availability of “standard” components and an open protocol means that smaller manufacturers can use communicating controls, opening the market up even more. In the very near future, every technician will need to work with communicating controls regardless of the brand equipment their company sells and services.

For more details regarding communicating control systems check out Unit 52 Heat Pump Installation, and Unit 59 Zone Control Systems in Fundamentals of HVAC/R. Many manufacturers also have some information online regarding their communicating systems, including

• Carrier Infinity
• Trane ComfortLink
• Lennox Icomfort
• Goodman ComfortNet
• Rheem Comfort Control System
• Emerson UltraTech
• ClimateTalk Alliance ClimateTalk

Interactive PowerPoint Presentations

Most PowerPoint presentations are used to as visual aids for a lecture or presentation. As such, they do not have to stand on their own. The speaker will fill in the details and keep the presentation engaging – or at least that is the plan. However, PowerPoint presentations can also be used as a self-paced leaning activity. This has the advantage of allowing the viewer to control the flow of material. If the presentation is designed for individual viewing, you can include more information in a slide, or you can narrate each slide to replace the live speaker. Try to layer the information so that it is presented a little at a time in a logical fashion, rather than all at once. For example, show a contactor with a title that names it: Contactor. Use the same picture on the next slide and add text that generally describes what it does. Then do a series of slides that label the parts: coil, contacts, L1 & L2, T1 & T2. The idea is to introduce the information a little piece at a time in a logical manner. After all the parts are located, have a series of interactive slides that ask the viewer to click on different parts.

Use shapes to make the clickable points. You can add shapes on top of a picture by gong to the “Insert” tab, clicking on “Shapes”, and clicking on a square or circle. Draw a square or circle over the area you want the viewer to click. It normally will draw a filled object. To make it transparent, click on the “Format” tab, click on “Shape Fill” and click “No Fill.” You can now see through the object, but the line is still there. You can leave the line as a general guide, or you can make it disappear as well. If you don’t want the line, click on “No Outline.” However, wait to do that until after you are finished designing the page because you won’t be able to see the object.

To make the object interactive, select the object, click on the insert tab, and click on “Action.“ A dialogue box will pop up that allows you to choose the action you want. First, you choose if the action is from a “click” or a “mouse over.” Then you can choose between a hyperlink, running a program, or running a macro. I like hyperlinks because they are relatively simple to do. The hyperlink can go to any slide in the presentation, an address on the internet, a file, or even another PowerPoint Presentation. If you know the viewer will have online access, you can hyperlink to manufacturer’s web sites to incorporate publicly available information in an organized fashion. Rather than just pointing your students to YouTube, the PowerPoint presentation can direct them to specific YouTube videos that fit in with the lesson.

PowerPoint Fast Lane

Let me start by stating that I am far from a PowerPoint Guru. But even an old-school whiteboard warrior like me can learn to use PowerPoint presentations to improve instruction. PowerPoint presentations are built like an electronic slide show. I suspect that if you are younger than 30 years old you might not have ever seen an ACTUAL slide show. Suffice it to say, making a PowerPoint presentation is SOO much easier than making an actual slide show. The slide show format displays pictures in a sequence while a presenter narrates or discusses the slides. PowerPoint presentations retain this overall organization, but they allow a great deal more flexibility. It is possible to add animation, audio, video, time the appearance of different elements, and use interactive responses just to name a few. However, the most common presentation is still a series of pictures. It can take quite a while to select pictures individually, place them, and add titles. This can all be done quickly by inserting a photo album. To create a presentation quickly, follow the following steps.

1. Take a bunch of cool pictures with your digital camera.
2. Always take more than one picture of each item using different light levels and angles. It does not take much longer and will save you time in the end. You can’t always tell the quality of the picture using the small LCD screen on the camera.
3. Import the pictures into a folder on your computer. Make sure the folder is located where you can find it and named something appropriate – “Way Cool Pictures”
4. Start PowerPoint and click on “Insert” in the ribbon at the top.
5. Click on “Photo Album” and then choose “New Photo Album”
6. In the box that opens, click on the “File/Disk” button at the top left to open a file selector dialog.
7. Navigate to the folder containing your pictures and select the pictures you want.
8. You can select individually by holding down the “Ctrl” key down as you click each picture; or you can select a group by clicking on one picture, holding down the shift key, and then clicking on the last picture.
9. After selecting your pictures, click “Insert” at the bottom right of the dialogue box.
10. The next dialogue box shows a list of your pictures. You can rearrange their order or delete pictures you don’t like here.
11. At the bottom of this dialogue box you can choose how many pictures per slide and whether or not you want a title.
12. Next, choose the type of frame around the picture and any theme you want.
13. Finally, click “Create” at the bottom and your new presentation will be created.
14. You can now go back and fill in the titles for each slide. Just click where it says “Click to add title” on the slide and type in the title for that slide.

If you are using Fundamentals of HVAC/R, you can download all the supporting PowerPoint presentations at Download. As I said at the outset, what I don’t know about PowerPoint presentations would fill a book. Fortunately I have friends in the know. Gary Reecher sent me this link to Microsoft’s site Twelve Tips to Better PowerPoint Presentations. It is well worth your time. If you would like to have someone do the heavy lifting for you, you can’t do better than the presentations the Dick Wirz puts together. You can find out more about his material at

Dick & Irene Wirz

Refrigeration Training Services, LLC

6609 Briarcroft Street

Clifton, VA 20124

703-830-6004

teacherwirz@cox.net

idwirz@cox.net

Do You YouTube?

Electronic social networking has made it possible for people to enjoy global communication with millions of people who share common interests. HVAC/R is no exception. Take a look around the web and you can quickly find many discussion forums, web sites, and media aimed at HVAC/R technicians. You have to exercise some discipline when perusing web materials because it is easy to while away hours of time reading and viewing content on subjects that you are interested in. YouTube is especially addicting because they have figured out how to keep feeding you video clips that are related to what you are watching. If you start looking at clips of compressors, more and more compressor clips will keep coming up in the side bar for you to view. However, my discussion is not how to avoid internet addition, but how to employ internet addiction for teaching purposes. The easiest way is simply to give your students unfettered access to the web, point them to a list YouTube clips, and stand back. This approach does come with some amount of risk because everything is on YouTube. The very openness of the format which encourages sharing and communication also aids in the transmission of inaccurate or even offensive ideas. There are oscillating parts on YouTube videos that are not attached to compressors! For this reason, many schools filter or restrict online material so severely that it is not really possible to use YouTube live. Many schools block sites like YouTube entirely. If that is the case, you can still view and download the videos at home and then take them to school. This gives you control over what is seen and allows your students access to the material. Although YouTube does not provide point and click ability to download their files, many people provide sites or programs to do it. I use a free program called YouTube Downloader. It is available on CNET, a trustworthy site for downloadable computer files. I then download the files onto a jump drive to take to school.

There are literally hundreds of video clips on YouTube that are helpful in HVAC/R, but my favorites are clips that show things you can’t see elsewhere. A gentleman in Australia has several clips of compressors he has cut open. Many of them operate. Seeing the movable scroll on a scroll compressor orbit as the compressor is energized is way cool! I must admit that seeing him cutting open compressors with a grinder, sparks flying appeals to the kid in me! Before you run out and start sawing up compressors, why not take a look at what he has already done. To help you get started on your internet addiction, I have included a short list of YouTube compressor videos to whet your appetite. The titles are hyperlinked, just click on the title to go to the video.

Open Scroll 3

Off with its head

Daikin Relucance DC Swing Compressor

30 HP Carlyle Semi

Kirby Reciprocating Compressor

Managing Large Group Labs

The easiest way to manage your lab is to have one lab instructor for every five students. I have actually taught lab classes where we had this ratio and it was a lot of fun. We were able to spend a lot of time with each student and we were able to do things you just can’t do with larger groups. So what if you have more like 20 students per lab instructor? It is still possible to give them a good lab experience, but a lot more planning and organizing will be required up front, and there will be things that are just not practical. One management technique is to split up large groups into smaller ones and schedule them at different times, effectively making several smaller lab classes. Of course this means you must spend more time than usual since you will be repeating the lab for each group. This may not be an option for everyone depending upon the number of instructors, students, lab equipment, and available lab time. For most of us, there will come a time when we have to work with larger groups in the lab.

A common technique is to have students work in groups. I try to avoid this if possible because it often means a couple of confident students do the work and the rest of the group watches and writes down the results. In group projects, you can see the 80/20 rule at work: 80% of the work is done by 20% of the people. However, this can be managed if you know it is going to occur. Ask every member of the group a question that requires an understanding of the process. For example, if the group is measuring the superheat on an air conditioning system you might ask different students

• What is superheat?
• What measurements are required?
• How did you arrive at the current superheat?
• What readings are necessary to use the manufacturer’s superheat charging chart?
• What does the system charging chart say the superheat should be?
• What does this system's superheat tell us about the system?

If they know they are going to be asked to perform a task or answer a question, they will at least pay more attention to what is going on.

Some skills are so important, every student must perform them for you individually. Lighting an oxy-acetylene torch is one example. An issue with large groups is simply the amount of equipment and tools available. Most of us would be hard pressed to come up with 15 oxyacetylene torch sets so that every student could have their own. Besides, I really do NOT WANT to have more than three rookies working torches at the same time. Once when I had a class of 18 students who needed to learn to braze, I worried about how I was going to teach all of them to handle an oxyacetylene torch safely. What I did was to demonstrate, as I always do and then ask questions to see what people remembered. We then went back over the procedure, paying particular attention to things that I felt they had missed the first time. Finally, I lined them up and had each student turn on the tanks, set the regulators, light the torch, adjust the flame, shut off the flame, and shut down the torch leaving it ready for the next student. If they hesitated, they repeated the process. I noticed that the students got progressively better, which was odd because the most confident students had stepped forward first. When I remarked to one student on how quickly and confidently he performed the task he replied “I saw it done 10 times before I had to do it.” In other words, the students waiting in line learned through the experience of their fellow students. This made me feel less guilty about having everyone wait in line to work with me. This method works well for procedures that can be demonstrated in a few minutes such as lighting torches, soldering, brazing, or installing gauges. If the students use their time wisely and pay attention to what is going on they will learn by watching others and everyone leaves with an important skill they did not have the day before.

Delivery Styles - Lecture

I am sometimes asked which instructional delivery system I think is best: traditional lecture lab, self paced, or computer aided and online. Like a trick question, the answer is all of the above. Each method has strengths and weaknesses. I have used each at different times in my career and enjoyed the advantages and suffered the frustrations of each of these delivery styles. Most people are familiar with the lecture format. In fact, to many people the other formats are not really teaching. I do not agree with that sentiment, but I understand why people sometimes feel that way. I will talk today about the lecture format and cover the others in later columns.

Undoubtedly, the lecture format is efficient at disseminating information to large numbers of people. If we are honest, it also appeals to the ham in most instructors: we like to talk! I will admit that I enjoy lecturing, and I believe my students enjoy my lectures. However, I may not be the most objective judge. Lectures can be engaging with good preparation and a well developed style. However, they can also be deadly. The derisive terms “talking head” and “chalk and talk” are well deserved. Did you ever see a video that is basically a picture of someone while lecturing? Usually they are hard to sit through. After watching a few I decided that the reason the videos of my lectures were boring was that the original lectures were boring. I was talking, and talking, and talking and I am sure the students were nodding off. Remember, your job is not to just cover all the topics, it is to teach your students. A big problem with lecture is that people do not tend to retain most of the information they hear, active participation is needed to retain the information. A few ideas to increase student participation are taking notes (not a big hit with students), asking students questions, asking leading questions, regularly entertaining questions from students, or engaging them in a dialogue. I like the dialogue format. Today, I don’t tend to talk to my students as much as have a structured discussion encouraging their participation and asking them questions. Repetition is also good. If something is important, don’t just say it once, say it several times using different approaches. After you think the students know the information, ask some questions to find out.

Speaking style and delivery is important, but can vary a great deal from one person to the next. In general, you need to be interested in what you are saying. Students can hear the interest and passion in your voice. They can also hear disinterest and lethargy. You need to be interested and excited about your field. Humor works for some speakers, everyone loves to laugh. Don’t feel compelled to tell a joke, just use humor if it comes naturally. Stay away from jokes involving off color, racial, religious, or political jokes. Jokes on yourself are fairly safe and students enjoy a laugh at the instructor’s expense. Most people find stories more engaging than a recitation of facts. Having taught for many years, I have a large body of stories to draw on.

Visual aids are great for creating interest. Rather than draw a crude diagram of something on the board, pass around examples of the real thing. If you have a video projector and document camera you can zoom in on parts and show details to the whole class that are not easily visible even to someone holding the object. The table in front of where I lecture is usually a mess because it is covered in stuff I brought in from the lab to show. The ultimate visual aid was a complete transport refrigeration unit sitting in the corner of the class room when we were teaching transport refrigeration. Students disassembled the unit, brought the frame and pieces into the class room, and then reassembled the unit in the corner. When I talked about the location of parts I could actually put my hand on the part on the unit. We gave tests using sticky notes attached to components and students were required to identify components. They would come up, look at the component labeled #1, and write down its name and function. That room is now used for an Interior design class and for some reason they did not want a refer unit in the corner, so we disassembled it and took it out of the room.

Powerpoint presentations can also help, but avoid letting the powerpoint presentation BE the lecture. Nothing is more boring than hearing someone read the text of a powerpoint presentation. I remember being surprised when several students mentioned to me that another instructor’s classes were boring. This instructor had really world class powerpoints that he had developed. They were complete with movement, animation, great details, and good photos. In fact I was rather envious of them. However, the students said they started to doze off as soon as the lights were out. They were not actively participating and they tuned out. This is not to say you shouldn’t use powerpoint presentations, just remember that they are a supplement, not a replacement.

Personally I feel that the biggest weakness of traditional lecture lab is the lab component when five people are assigned to work together on something that really only requires one person. I will leave that discussion for next time.

A Father's Legacy

When I was 13 years old my father started Stanfield Air Systems. He moved his family to a city he had never lived or worked in to start a brand new business in a field he knew little about. For capital, he used his life savings and a line of credit. It was not until many years later when I had my own family that I truly understood the courage it took for my parents to do this. He gave up a secure job with a major corporation that had just offered him a promotion. He was one of a class of businessmen recruited to start air conditioning dealerships. After five years, he was the only one of his class still in business. Stanfield Air Systems survived major builders declaring bankruptcy and not paying, strikes by compressor manufacturers when equipment was hard to get, and more than one economic downturn. Because of dad’s pioneering spirit, Stanfield Air Systems has frequently been in the vanguard of new or unique technology. We put in solar systems in the late 70s and water source heat pumps in the 80s. Some of the more unusual equipment we installed included Space Pack high velocity systems, Amana EG units, and Arkla Servel absorption chillers. People around Athens learned that if you wanted to do something out of the ordinary and be successful, you wanted dad’s company to do it. One thing that has stayed constant is a commitment to quality. He sold himself and his company, not any particular brand and certainly not price. His price was usually higher than the competition, but he offered services and quality not available elsewhere.

I have a brother and a sister, and we all work in the air conditioning field. My sister now runs Stanfield Air Systems and they are doing great. They remain the company people who insist on quality turn to. I am especially proud of the pictures in my book that came from Stanfield Air Systems showing what a good installation looks like. My brother is a top service technician – for the competition. He has customers that call and ask for him by name because he has the same commitment to quality service and honesty as our father. And I teach air conditioning at Athens Technical College. I am proud to say that many of the technicians at Stanfield Air Systems graduated from Athens Tech. For that matter, so did many of the technicians at competing companies. In Athens Georgia, if someone comes to your house to install or service heating and air conditioning equipment, there is a pretty good chance that they are a Stanfield, work for a Stanfield, or were taught by a Stanfield. My father’s legacy includes a legion of air conditioning professionals and three children who are proud to call him dad. I know my recent success started in 1968 when a courageous entrepreneur put everything on the line to start a new company in a new town. Happy father’s day dad!

A Father's Legacy

When I was 13 years old my father started Stanfield Air Systems. He moved his family to a city he had never lived or worked in to start a brand new business in a field he knew little about. For capital, he used his life savings and a line of credit. It was not until many years later when I had my own family that I truly understood the courage it took for my parents to do this. He gave up a secure job with a major corporation that had just offered him a promotion. He was one of a class of businessmen recruited to start air conditioning dealerships. After five years, he was the only one of his class still in business. Stanfield Air Systems survived major builders declaring bankruptcy and not paying, strikes by compressor manufacturers when equipment was hard to get, and more than one economic downturn. Because of dad’s pioneering spirit, Stanfield Air Systems has frequently been in the vanguard of new or unique technology. We put in solar systems in the late 70s and water source heat pumps in the 80s. Some of the more unusual equipment we installed included Space Pack high velocity systems, Amana EG units, and Arkla Servel absorption chillers. People around Athens learned that if you wanted to do something out of the ordinary and be successful, you wanted dad’s company to do it. One thing that has stayed constant is a commitment to quality. He sold himself and his company, not any particular brand and certainly not price. His price was usually higher than the competition, but he offered services and quality not available elsewhere.

I have a brother and a sister, and we all work in the air conditioning field. My sister now runs Stanfield Air Systems and they are doing great. They remain the company people who insist on quality turn to. I am especially proud of the pictures in my book that came from Stanfield Air Systems showing what a good installation looks like. My brother is a top service technician – for the competition. He has customers that call and ask for him by name because he has the same commitment to quality service and honesty as our father. And I teach air conditioning at Athens Technical College. I am proud to say that many of the technicians at Stanfield Air Systems graduated from Athens Tech. For that matter, so did many of the technicians at competing companies. In Athens Georgia, if someone comes to your house to install or service heating and air conditioning equipment, there is a pretty good chance that they are a Stanfield, work for a Stanfield, or were taught by a Stanfield. My father’s legacy includes a legion of air conditioning professionals and three children who are proud to call him dad. I know my recent success started in 1968 when a courageous entrepreneur put everything on the line to start a new company in a new town. Happy father’s day dad!