Hilmor Scholarship Winners

Those of us who have been involved the HVACR industry sometimes wonder where the bright, energetic, new techs are going to come from. The need for more trained technicians is critical to the industry’s continued success. Recently, Hilmor showed us that the technicians can be found if we offer the right incentives and look hard enough. Hilmor, a brand new HVACR tool company offered three national scholarships in their first year of business and received over 500 applicants nationwide. Clearly there is some untapped talent out there. They chose three winners from among the 500+ entries: David Hall, Francisco Iniquez, and Kenneth Chavez. You can view their stories online at Hilmor’s web  page HERE

Watching these three young men describe why they wanted to study air conditioning it hit me: they are out there – we just have to find them. Their stories are similar to thousands of other young people who want to improve their life and are willing to work hard in order to do it. We need to show them that our trade offers that opportunity. I am proud to say that David studies at my school, and he has a bright future ahead of him. I know him personally, and I know he is exactly what this industry needs. I am sure Francisco and Kenny will do the industry proud as well. Take a look at the videos and think about the thousands of other people who could tell similar stories – then go out and find them.  They are out there.

How's It Flowing?

When air, water, refrigerant, or any fluid flows through a pipe, the flow can be characterized as laminar or fluid. I can hear you saying “what does this have to do with HVACR?” It applies to how refrigerant flows through piping, how air flows through ducts, how air flows across coils, and how refrigerant flows through those same coils. In short – it applies to pretty much everything in HVACR!

Laminar means in layers. Laminated furniture like you find in most schools has a thin layer, or laminate, on the surface to make it pretty and usually cardboard or glued together sawdust underneath to make it appear substantial. In laminar flow, the stuff on the top stays on the top, the stuff on the bottom stays on the bottom: there is no mixing. In turbulent flow, the fluid swirls all around mixing everything together and creating all sorts of eddies and whirlpools. If you turn on a water faucet that does not have an aerator on it, the stream of water is laminar. The water falls straight down without much mixing. After it hits the sink you have turbulent flow – swirling all around and mixing. Laminar flow is preferred in refrigerant piping, water piping, and ductwork. This is because the eddies, whirlpools, and swirling found in turbulent flow add a great deal of resistance to flow.

For example, take a bunch of people trying to leave a crowded room. If they file out in an orderly line moving in the same direction, they can all get out faster than if there is a lot of pushing and shoving with people going off in all directions and running into each other. To get fluid through a pipe or duct with the least amount of energy loss, laminar flow is the way to go.

High velocities tend to create turbulent flow while low velocities create laminar flow. That is why the resistance to flow increases so dramatically as pipes get smaller. Velocities increase and the flow goes from laminar to turbulent, increasing resistance to flow within the fluid. Its not just that the cross sectional area is smaller - the fluid is getting in its own way as it tires to go through the pipe.

In heat transfer coils such as evaporators and condensers, we need turbulent flow. In heat transfer, all the swirling becomes an asset. Turbulence makes more of the fluid contact the surface of the pipe and slows down the fluid, which helps it transfer more energy. This is why coils have features such as rifling, twisted tubing, or turbulators to encourage swirling and mixing.

Random Puzzle Assembly

Many students trying to troubleshoot HVACR systems have difficulty navigating the sheer amount of data one can collect. If you go about just collecting a lot of data, it does not take very long to confuse yourself. I often see people taking resistance, voltage, and current readings on just about every conceivable location on the system without having a clear idea why they are taking the readings. This is like trying to build a 1000 piece jigsaw puzzle by just randomly trying to fit pieces together without looking at the shapes or color patterns on the pieces. When building puzzles, it helps to have a plan. There are different plans – outside edges first, organizing pieces by color, or organizing pieces by shape, but having a plan improves your chances of success. Troubleshooting is the same way. You should have a plan to organize your data collection into something meaningful. You should know why you are taking a voltage, resistance, or current reading before taking the reading. Ideally, each measurement you make should eliminate an area of inquiry. A simple example is checking the power supply to the unit. If you read the correct incoming voltage, you can eliminate that as a source of the problem. But if you don’t read the correct voltage at the power supply, then there is no need to check anything inside the unit until you have solved the power supply problem. There are probably as many systems as there are technicians. It is not too important what your system is, so long as it is based on an understanding of how the equipment functions and proceeds logically. For a non-functioning component, I generally want to know if that component is receiving the correct voltage. If it is, then I need to take a closer look at the component. Otherwise, I need to check the circuit that supplies voltage to the component. Many technicians check the line voltage and control voltage first. This does not take long and covers a large number of problems. Another technique is to start at the thermostat and work towards the non-functioning component until you find a break in the circuit, or eventually reach the component. The key point is that each piece of data you collect should tell you something. This will allow you to take far fewer readings and isolate the problem much faster.

R-22 Conversion - What to Avoid

After reading a lot of technical literature, attending several talks and seminars on R-22 conversion I have developed the following cautions on R-22 conversion.

First and foremost – if you convert a system from R-22 to ANY replacement refrigerant, you are conducting a field experiment on the customer’s equipment using their money. Make sure the customer understands that they are paying for an experiment which may or may not end successfully. I think I would get that in writing.

Since all the replacement refrigerants are zeotropes, they should not be used in flooded systems because they will fractionate in the evaporator.

Since all the replacement refrigerants are immiscible with mineral oil, they should not be used in systems with large receivers (without changing the oil to POE) because the mineral oil will separate and float on top of the refrigerant in the receiver.

Some of the replacement refrigerants have trace amounts of hydrocarbons or POE to help prevent oil logging in the coils and lines. This works well in many systems, but it does not help in the receiver where there is not much refrigerant movement.

DuPont says that the churning in accumulators discourages separation in the accumulator. However, they also say that you may need to add 10% POE if you have oil return problems. 

I am nervous about heat pump accumulators – especially in cold weather when a large amount of the charge is just sitting in the accumulator.

You should NOT weigh in the same amount of replacement refrigerant as R-22 because all the replacement refrigerants are less dense than R-22. A general rule is somewhere around 75-80%.

You should NOT just try to match the pressures you are used to seeing with R-22. A better indicator would be to measure the system subcooling and superheat and shoot for “reasonable” numbers.

You should replace all O-rings and Schrader valve cores before putting in the new refrigerant. O-rings can shrink when exposed to the new refrigerant creating a leak where none previously existed.

You should NOT just add the new refrigerant on top of the R-22. If you do that, you are creating your own special blend which is not EPA SNAP approved.

Just because a refrigerant matches the pressures of R-22 does not mean it will match the mass flow rate. If the mass flow rate is too different from R-22 the metering device won’t work correctly.

Make sure any refrigerant you use is EPA SNAP approved for the application. Any reputable refrigerant will have an ASHRAE refrigerant number and safety rating – not just a trade name or number.

One way to be sure what you are using is safe is to only buy refrigerant from recognizable manufacturers at normal supply houses, not online.

Under NO CIRCUMSTANCES should you use any of the “Organic” replacement refrigerants available on the internet. The “organic” components are propane and butane. They don’t have trace amounts of hydrocarbons, they are ALL hydrocarbon. These refrigerants are NOT EPA approved and they are NOT safe to use in a system which was not designed for flammable refrigerant.

If the customer has already purchased some “organic” refrigerant and tried charging their system, I would not work on the system. It is an accident waiting to happen.

Acetylene Cylinder Safety

I am writing on this subject because I saw a report on CNN discussing an explosion in the back of a car set off by energizing the electric trunk latch. It blew off the trunk and mangled the rear end of the car. Fortunately, nobody was hurt, but the possibility of a lethal accident was certainly there. The fireman that is interviewed mentions that there was an acetylene cylinder in the back of the car which leaked, and the trunk latch set it off. The acetylene should not have been there at all. Acetylene cylinders contain liquid acetone that is stabilized in a porous, cement like material. The acetone is there to dissolve the acetylene gas stored in the cylinder. Acetylene gas is unstable above 15 psig, but must be stored at a much higher pressure to store enough for practical use. Dissolving it in the acetone allows the higher pressure without creating a bomb. The cylinder regulator reduces the acetylene pressure to less than 15 psig. The actual pressure depends on the regulator setting. Note that you should NEVER adjust an acetylene regulator to a pressure above 15 psig.

Since acetylene cylinders contain liquid acetone, they should NEVER be laid on their side. They should ALWAYS be transported in the vertical position, securely fastened to the vehicle. Laying an acetylene cylinder on its side can result in the liquid acetone leaking out into the valve and regulator – setting up a very hazardous situation. You also should not have cylinders in the back seat behind you. Not just for the explosion hazard, but also because of the shifting weight in case of an accident. Any heavy objects behind you will crush you in an accident. My wife’s cousin was killed many years ago transporting cylinders in the back of his car. They crushed him in an accident that would otherwise probably not have killed him. That is why working trucks have a metal cage between the driver and the stuff in the back – to save your life in an accident. Basically, what this all means is that THERE IS NO SAFE WAY to carry an acetylene cylinder in your Prius! If you are going to transport torches or cylinders, you need a properly outfitted truck – not your family sedan.

RSES Annual Conference

I just returned from the Annual RSES Conference in Charleston, South Carolina. What a great experience! Of course there were many great speakers on a wide range of current HVACR topics, from Building Envelope Testing to Transcritical CO2 Refrigeration Systems. All the sessions were great. However, the thing that impressed me the most was the level of training and experience demonstrated by the people attending the convention. I often found myself sitting in a whole room full of experts. Because the people attending are practicing industry professionals, the level of questions and discussion in the sessions was quite high. And truth be told, the folks gathered here were not just any industry professionals, but the people that go the extra mile. They invest their time and money in educating themselves about a field in which they are already very well versed. The discussions in the halls while people were just waiting for the next event were both interesting and informative. One of the main reasons for attending an educational conference is to be energized. Talking with other professionals and sharing their enthusiasm for the trade inspires you. You don’t have to wait for the annual meeting to experience this, you can also meet with other highly motivated professionals at a local RSES meeting, because meetings of local RSES chapters occur throughout the year. If you want to be immersed in a professional culture that inspires and elevates its members through education, you belong in RSES.

Flooded HVACR Equipment

Areas that have experienced flooding from Sandy have a big cleanup job and lots of rebuilding ahead. Make sure your students know to be careful when working on equipment that may have been flooded. Even after drying out, the corrosion and debris left behind can make the controls and motors inoperable. Worse, they can be dangerous. While it is possible that many parts of the system may still function properly, it is really a gamble to operate equipment that has been flooded. Safety controls that have been under water cannot be relied on to work. Silt and debris can create potential shorts or prevent proper mechanical operation. This can turn a normal malfunction into a potentially dangerous situation. For example: a blower motor on a furnace starts, but fails after a few hours of operation. The limit does not shut off the burners because its contacts are shorted together, the furnace overheats and burns the house down.

Another concern is for the health of the building occupants. Flood waters contain all types of things that you really don’t want in your air conditioning system: chemicals, gasoline, dead animals, and sewage to name a few. Coils , equipment cabinets, and insulation will all retain some of these undesirable things even after the water has receded. Technicians may be asked to repair flood damaged equipment, but in most cases the proper repair is more costly than replacing the equipment. It is hard to tell someone who has just lost most of their possessions that you cannot fix their flood damaged equipment, but that is exactly what you should do. Then there is the matter of duct work: obviously a good place to catch things. Again, cleaning may not really be practical.

A danger to technicians working in a previously flooded area is the muck they will often be working in. They will be walking, crouching, crawling, sitting, and laying on this muck when they go in the house to look at the equipment. Again, this is not just mud. This is a combination of nasty stuff that is definitely hazardous to your health. For more information on flood damaged equipment check out the AHRI page on flooded equipment.

Service Tech's Secret

Most of the truly outstanding technicians that I have met have one thing in common – they read a lot. Reading is their trade secret. One example of this is Chris Mohalley. He is the Genteq™ Certified Master ECM Trainer. He has created a nationally-recognized ECM training program and he travels the country spreading the ECM gospel. He serves as a NATE Technical Committee SME, a NATE proctor and ARI Chief EPA Examiner. He holds so many NATE Certifications that his shirt looks like a quilt. In short, he knows his shit. So I asked him one time how he became so erudite. His response, he reads a lot! Personally, I try to read something related to my field every day. At least once a week you should find something that peaks your interest and dig a little deeper. Information is now easier than ever to access. Take advantage of it! The amount of information that can be readily accessed on the internet is really staggering. When the EPA “Final Ruling" on ozone depleting substances was published in May of 1993, I had to go to the library at the University of Georgia to view it in the Federal Register. Now you can pull up the Federal Register online anytime you want. If you are not familiar with the Federal Register, it is the official government publication containing all the announcements, pronouncements, and new regulations of all Federal Agencies. This is where they post proposed rulings, and what are called “Final” rulings. Basically, a “Final Ruling" means that now it is law. There will definitely be more rulings to come. If you want to know exactly what the rules really say without any filtering by someone else, you want to read them for yourself at the Federal Register. That said, the Federal Register is some of the most tedious reading I have ever seen. Further, there is a lot of it. The Federal Register is published weekly. In its paper form, it is about the size of a phone book for a city the size of Athens Georgia. In other words, it is might be possible to read ALL of the Federal Register by yourself, but that would be about all you did. Thankfully, search engines let us look for all the juicy parts without reading the entire tedious tome.

Thankfully, there are many outlets for HVACR information which are really interesting, such as the RSES Journal. This month’s Journal has a great article on micro-channel coils and why manufacturers are looking at using micro-channel evaporator coils. You might even pick up a copy of a text, like Fundamentals of HVACR and read it one unit at a time. At one unit a week, you will finish the book in a little over a year and a half – there are 92 Units. You can pick up a lot just by looking at the material posted by manufacturers and distributors online. One caveat on web surfing – realize that the freedom for anyone to publish on the web means that there are products, policies, and procedures espoused that may not be in your best interest to pursue. A case in point: the flammable R-22 replacement refrigerants that are NOT EPA approved. They are mixtures of propane and butane. They absolutely should NOT be used to replace R-22 in an existing system. Remember, nothing in that original system was designed with a flammable refrigerant in mind. Always look to see who is posting the information. If you read a lot you will learn to sort out the fact from fiction. Thanks for reading!

NOT COOL

Not too long ago a morning television show did a “sting” type of operation on several HVACR contractors that were called out to service a system that had one simple problem. The good news is that all the technicians found the problem quickly. The bad news is that all the technicians then tried to pad the bill by replacing unnecessary parts. You don’t need to cheat people to make money. In fact, I think that cheating people ultimately ends in losing customers. Most satisfied customers will refer you to friends and family. The HVACR business works best with long term repeat customers, not a long string of patsies.There was once a contractor in Athens who specialized in getting their foot in the door and then condemning equipment. They are no longer in business. They literally ran out of people who would do business with them. When you cheat your customers, you are slitting your own throat. It does not take a high profile television program sting for folks to figure out something is wrong. Eventually, your customers will catch up to you. When they do, everyone they know will know about it.

There is nothing wrong with making a profit, and there is nothing wrong with being paid well for your time, expertise, and investment. So be up front and charge people for your time, expertise and investment, not parts they don’t need. There is also nothing wrong with offering premium services. If you want to sell setback thermostats or other system improvements, you should make your argument based on the increased comfort, energy efficiency, or convenience that the customer will enjoy. We make money by solving problems for people, not creating them.

Synthetic Marijuana Kills!

I found out recently what killed a promising student in my program this past year. His heart was stopped by synthetic marijuana. I have no idea why he was using it, I only know that it killed him. He was a promising young man with significant ability that is now lost. He left behind a son that he cared deeply for. One of his motivations for learning a trade was to improve life for his family. I admittedly know very little about this stuff, so I am providing some links to articles about it. Wikipedia Article   National Institute of Health

What I do know is that it makes no sense to inhale any kind of drug laced smoke into your body. Before FDA approved drugs are even tested in limited quantities on people, they are extensively tested in animals for safety. With these designer drugs, the customers are the lab rats. My message is simple: if you use this stuff - stop. If you know someone else who uses it - stop them. It is literally a matter of life and death.

YO MOMMA

Nobody loves you like your momma. Regardless of your shortcomings, failings, or mistakes – your momma loves you. Perhaps that is why “yo momma” put downs are so successful at stirring people up. We all know that our momma is the one person in this world that loves us unconditionally. Attacking our momma is worse than attacking us. I am an expert on mommas because I have one and I am married to another.  Mommas are the toughest people on earth. Only a momma can endure nine months of physical hardship leading up to birth. A weaker being would not make it. The reward for enduring months of physically exhausting body changes is birth: the most physically excruciating event a human can experience. How do I know this? I was with my wife both times when she gave birth to our two beautiful children. She endured 24 hours of labor – the first 12 hours with no drugs – just backrubs. The final 12 hours with intravenous narcotics to “take the edge off.” I am pretty sure I could not have done that. Like I said – mommas are tough. Nobody is more interested in your well being than your momma. I know my own mother kept me from harm more than once when I was too stupid to recognize the life hazards before me. I specifically remember her sternly warning me to keep out of the old television set in the basement – telling me that you could receive a fatal electrical shock even if the set was unplugged. I thought, but did not dare say: “That is stupid. You can’t possible get shocked if it is not plugged in.” Neither I nor momma knew anything about capacitors, but she had read that experimenting inside the TV was dangerous, so she kept me away. Years later I learned that CRT screens had large capacitors capable of holding thousands of volts – enough to deliver a fatal shock! Momma was right! Momma knows things you don’t even if she can’t explain them. Your momma is more interested in your success than you are. At a recent high school honors night it was revealed that my son was tenth in a class of approximately 300. He thought that was pretty good. His momma wanted to know why he was so far down the list. She knows that he is extremely talented and has been coasting a bit. His sister just graduated from Vanderbilt with a degree in Biomedical Engineering and has accepted a job making more than I did after 20 years of teaching. I noticed that the proudest people with the broadest grins were not the graduates, but the mommas, witnessing the fruits of many years of labor. So let me tell you what I know about your momma – Yo Momma is AWESOME!