Thank the Tool's Inventor

I love reading about the history of people who have made contributions to our industry. You might even say they have made major contributions to society. Think about a world without air conditioning, and then thank Willis Carrier. But contributions to society can be less grand than being known as the father of modern air conditioning. What about creating a tool which is used word wide every day? I would say that deserves recognition as well. It certainly does deserve my gratitude when I use the tool. We often use and take for granted tools and devices that someone before us created to make their life easier. They end up making life easier for a lot of us. They have made my word a better place.  Have you ever tried doing a job and NOT had the right tool? It is pretty frustrating. So when you use a tool that makes your life a bit easier and helps you accomplish more than you could without it, think about and thank its creator. I read a great article by Dan Holohan in the December 2014 issue of Plumbing & Mechanical magazine in which he traces the history of a very common tool, the Stillson wrench. If you are like me, you may be asking yourself – “What is a Stillson wrench?” I guarantee you have used one, only you might not know the correct name. You may call it a pipe wrench (as I often have.) Now think about how many pieces of pipe you have turned with a Stillson (pipe) wrench. How else would you have done that? It was invented by Daniel Chapman Stillson and patented by him on October 31, 1865. Next time you use one thank Mr. Stillson by calling it by its proper name, the Stillson wrench. He truly did make the world a better place.

If you want to know the back story on this incredibly useful tool, pick up a copy of the December issue of Plumbing & Mechanical magazine or visit their web site pmmag,com and read about the tool’s inventor.    

Motor Frames by the Numbers

Two standards organizations publish motor frame standards: National Electrical Manufacturers  Association (NEMA) and the International Electrotechnical Commission  (IEC). Do you know why a NEMA Frame 56 motor is a 56 motor? I admit, until recently I did not. I just knew that if two motors have the same frame, they will mount in the same place. That does not necessarily mean that they are interchangeable, just that you can physically interchange them. However, I did not know what the 56 stood for in a 56 frame motor. It is really pretty simple. The number in a NEMA Motor frame designation describes the distance from the center of the shaft to the bottom of the mounting base in eighths of an inch. So a 56 frame has a distance from the center of the shaft to the bottom of the base of 56/8, or 7 inches. Of course, there are other dimensions that are set by frame size, but that particular dimension gives the frame its name. Maybe your machines use motors with IEC fame designations. The frame number still describes the distance from the shaft center to the base, but in millimeters. So an IEC 112 Frame motor has a distance from the shaft center to the bottom of the base of 112 millimeters. If you are measuring in centimeters that is 11.2 centimeters. As in the NEMA frame size, the IEC frame size standardizes many dimensions. Both standards have many dimensions that are described but not standardized. This means that manufacturer will report these dimensions, but they will not necessarily be identical from one motor to another. Baldor has a couple of good pdf reference pages which show the dimensions for each type of frame. You can find these at

NEMA  
IEC        

Technically Speaking

Throughout my entire career in HVACR, technology has been changing how we work and what we work on. During this time, people have been continually complaining about the changes wrought by new technology. I can still remember an older technician in the late 70’s (yes I was actually working way back then). He was bragging in the parts house about replacing the primary control on someone’s oil furnace. It had a newer cad-cell type sensor which he did not understand, so he retro engineered the system to use a stack switch. Basically, he charged the customer to downgrade their equipment because he did not understand the controls. Another tech agreed, saying those cad cell things were not trustworthy. Then he added that he did not work on heat pumps – if a customer had a heat pump, they had to call somebody else. Today these guys would not be able to work – there just are not enough systems that meet their limitations. Many folks today don’t feel comfortable with communicating systems, but these systems are here to stay. In unitary product lines, communicating systems are still just the higher end. The thing is, most air conditioning manufacturers are offering them now. Virtually all mini-split, multi-split, and VRF systems use communicating control technology. And in case you haven’t noticed, those systems are here to stay as well. Sure, new technology can be a pain – especially brand new technology. Early adopters often pay a price for being the first with the new stuff. However, bitching about having to learn something new won’t keep the world from changing. You will just be left behind. As I age, I understand the pain of the old techs who just want to do the stuff they with which they are comfortable. I become less flexible both physically and mentally as I age, so I find it necessary to study harder to keep up with current field technology. As I see it, I have a choice – I can complain that the future will be different than the past, or I can work hard to keep up with changes in this field I love.    

Can-Do Versus Can't-Do

Are you a can do person or a can’t do person? Here is a way to find out. When presented with a challenge, do you start by looking for ways to get things done, or are you more focused on why it can’t be done? There are certainly obstacles to accomplishing anything, so identifying those obstacles is important in order to succeed. However, it is easy to focus on the problems so intently that you don’t allow room for any answers. Why should you want to be a can do person? In short, because can do people accomplish things. People who look for solutions persistently generally find them. They are often rewarded financially for consistently accomplishing things. Who do you want working on your behalf – someone with a track record of accomplishments, or someone who can point out all the reasons “it” can’t be done? People who look for obstacles seldom accomplish anything because they manage to convince themselves that “it” can’t be done. They are also rewarded accordingly. 

Another characteristic of a can-do person is the willingness to work beyond the minimum requirement. They will generally not be the first out the door at the end of the day and they take on extra duties or work without a lot of griping. By taking on new challenges, they are able to show their ability to do more than their present position. This can lead to promotions – and yes – financial reward. Can’t-do folks use such phrases as “they don’t pay me enough to…”, or “that is not my job!” They never demonstrate they can handle any more than their present position, so they never advance. I am not going to promote you and pay you more to see if you can do more – you have to demonstrate your ability to do more first. Again, if you need someone to help you, who are you going to ask? 

It is true that good workers are rewarded with more work to do. That is probably why 20% of the people do 80% of the work. That is often seen as a disincentive to work hard. However, these folks are also rewarded with promotions and financial incentives. They grow as a result of taking on more challenges. My father says that some people have 10 years of experience, while others have one year of experience 10 times. Again I ask – which one do you want working for you?  The good news is that having a “can’t do” outlook is not a genetic condition – it can be rectified. You CAN DO IT! 

Turbo 200 Capacitors

NOTE: - This is a re-posting - I got Mona's e-mail wrong on the first one.
Have you ever had to replace a dual capacitor only to find you do not have the right one on the truck? There are so many different possible combinations it is nearly impossible to have every one you might need. Amrad Engineering makes capacitors here in the USA. They make replacement capacitors which have a wide range of capacitors built into a single part called the Turbo 200. With these, it is possible to replace most any dual capacitor you need. These capacitors are great for teaching students about series and parallel capacitors. Basically, the Turbo 200 is 6 capacitors connected together at the center post. Any two outside connections are essentially in series. Measuring the microfarad between any two outside terminals shows the effect of capacitors wired in series. Jumping any two outside terminals puts those two capacitors in parallel. Placing a jumper between any two outside terminals and measuring the microfarads between either outside terminal and the center terminal shows how capacitors connected in parallel work.  Amrad engineering is offering a free kit to all HVACR instructors. They want to send out a kit of their products with instructions to schools all over the country to promote their products. The stuff they sent me was fantastic. Here are a couple of pictures of the kit.

To get a kit for your school contact
Mona Tompkins Amrad Engineering
1-800-445-6033

mtompkins@yahoo.com

EPA Announces R-22 Allocations for 2015 - 2020

The EPA has released their R-22 allocations for 2015 – 2020, and it looks like the days of free-flowing R-22 are about to come to an abrupt end. To put things in perspective, the R-22 allocation for this current year, 2014, was 51 million pounds. The allocation for 2015, coming up in a few months, is 22 million pounds. That is just over 43% of the 2014 allocation. From there the cutbacks are more gradual with a reduction of approximately 4 million pounds each year until 2020 when the allocation is 0. Trying to figure out R-22 prices has been a bit difficult these last few years. They have spiked twice but then gone back down as supply increased. This time look for the high prices to last  because there will be no turning the tap back on this time. The main question remaining is how long demand for R-22 will continue. Although there is still a very large installed base of R-22 air conditioning equipment, it is starting to get old. As older equipment fails and supplies tighten, it will be increasingly difficult financially to keep an older R-22 system operating. I remember with R-12 and other CFCs, prices climbed high enough to kill demand. A local wholesaler took a bath on a large quantity of 502 just to get rid of it because nobody wanted it at the “market” price. Consider that a dry ship unit costs about the same as a 410A builder grade, but you still have to buy the refrigerant. It is conceivable that a dry ship unit charged with R-22 at inflated prices would be as expensive as replacing both the condenser and evaporator with a builder grade 410A system. Who would want to keep their old system if it costs as much as a system with current technology, higher efficiency, and a refrigerant that is still available? To read more about the EPA's ruling, check out

https://www.federalregister.gov/articles/2014/10/28/2014-25374/protection-of-stratospheric-ozone-adjustments-to-the-allowance-system-for-controlling-hcfc

DOE Small Motor Efficiency Standards for 2015

You may have missed the news about required small motor efficiency minimum standards while you were focused on refrigerant changes; regional efficiency standards for air conditioners, furnaces, and heat pumps; and trying to stay ahead of the latest news on climate change. I know I did. I was looking at the Grainger web site the other day and up popped a bulletin regarding the Department of Energy requirement that certain small electric motors 3 horsepower and under meet a new minimum efficiency requirement beginning in March, 2015. I immediately thought “oh bother,” that would include most of the motors we deal with in residential HVAC. Then I looked up some details and breathed a bit easier.  Motors which are exempt include multispeed, enclosed, specific purpose, or special mounting bracket. That just exempted most of the motors in residential air conditioning equipment. If you deal with regular mount, general purpose, 42, 48 or 56 frame capacitor start or capacitor start-run motors, you WILL be affected. An example might be ventilation fan motors. Grainger was not saying replacement motors would not be available, just that they would now have run capacitors and would be longer due to the extra windings required to meet the new efficiencies. Basically, this DOE ruling makes what was once the premium, high efficiency motors the minimum motor design for certain motor types defined by NEMA. I found several links with discussion and details on this requirement. They are listed below. You might want to take a look at some of these links to determine if you work with any of the affected motors. That way you can develop a replacement strategy before you get to a job and find that you will not be able to replace the old motor with another just like it.

Baldor http://www.baldor.com/news/article.asp?id=1014

US Department of Energy  http://www1.eere.energy.gov/buildings/appliance_standards/product.aspx/productid/40

Weg Industries http://ecatalog.weg.net/files/wegnet/WEG-motor-global-energy-efficiency-legislations-2015-and-beyond-energyeffleg-training-english.pdf

Design News   http://www.designnews.com/author.asp?section_id=1365&doc_id=271471

NOx Nox Who's There?

Cracked. Cracked who? Cracked heat exchanger. OK – not the funniest knock knock joke – especially if it is YOUR furnace. Low NOx emission inserts are causing pre-mature furnace heat exchanger failures. You can read more about this at http://ncidavid.blogspot.com/

I want to talk a bit about what NOx is, why an insert can help reduce NOX emissions, and why NOx inserts can cause trouble. NOx is a generic term for nitrogen compounds NO and NO₂ which are formed when nitrogen is present during combustion at high temperatures. These are major contributors to air pollution and acid rain. Laws requiring reduction of NOx emissions in areas of particularly high air pollution (California) have required the development of low NOx furnaces. Since the air is 78% nitrogen, any combustion process that uses air for its oxygen source has lots of nitrogen present. NOx will only form at high temperatures, but the burners in gas furnaces are definitely hot enough to form NOx. One quick and easy solution is to put something in the flame to cool it down. NOx rods and NOx inserts work by cooling the burner flame temperature, thus reducing the NOx emissions. These NOx rods or inserts are typically metal. Stick some metal in the flame, cool it down, and you have a low NOx furnace. The problem is that metal held directly in a flame eventually burns up. It does not burn quickly, but it does burn. That is why we don’t want the furnace flames actually touching the heat exchanger. The heat exchanger material cannot withstand direct flame contact, called impingement. NOx inserts stick inside a tubular heat exchanger. Unfortunately, the insert eventually degrades from being exposed to the flames. In some cases, it can twist or deform and change the flame pattern. This can cause the burner flames to touch the sides of the heat exchanger, and the heat exchanger fails prematurely. Before the heat exchanger fails, the furnace will be producing higher levels of carbon monoxide and carbon particulates because of the change in flame pattern. So you trade one type of pollution for another. If you work on furnaces with NOx inserts, be sure to check them – and watch the flames to see that they are not touching the heat exchanger. If you work in an area that does not require the NOx inserts, you can solve the problem by removing them. However, now you are increasing the amount of air pollution the furnace produces. Low NOx burner technology does exist – where NOx reduction is achieved through burner design, but I don’t know if there are any true low NOx burners for residential appliances. Keep an eye out for furnaces with low NOx inserts. It might be worth a few extra moments to wath the flame pattern and measure the CO in the flue gas. Abnormally high CO might indicate a developing problem. 

Playing with Your Phone on the Job

Many companies now issue company cell phones to their service techs. The phones are intended for communication, so the company can find the techs and talk with them virtually anywhere, anytime. Now those phones may need to be considered part of the technician’s toolbox. There are already many great apps, including free pressure-temperature apps – usually from refrigerant companies. Equipment and parts manufacturers have started producing apps for looking up parts and equipment service specs. Now you can use your phone or tablet to read the system pressures, line temperatures, superheat, and subcooling. Stride Tools (Imperial) released the i-manifold last year. It is a four port manifold without a display. It sends the information wirelessly to your phone or tablet, and your device becomes the display. Since the display is literally on a small computer, the app can do all kinds of cool things. For one, they have wireless thermometers that can work with the i-manifold to determine system operating conditions, capacity superheat, and subcooling. But wait – there’s more! Now Yellow Jacket has come out with a small device they call the mantooth. It connects to the system and has a tethered temperature probe. It also has no display, but sends the information to your smart device via Bluetooth. So you can see system pressures, temperature, superheat, and subcooling all on your phone. The advantage of this device is that you don’t have to fill up a hose with refrigerant to get a reading – so refrigerant loss is minimal. The “short” gauge concept is perfect for simply testing system performance. Another well known manufacturer is also testing “short” gauges that connect to smart phones and tablets. Their devices are also “short” gauges – eliminating the refrigerant loss from connecting hoses. Their gauges do have their own display as well as connecting to your device through Bluetooth. They are developing wireless thermometers to work with these gauges. Again, you will be able to see all relevant system operating conditions on your smart device and you won’t have to lose several ounces of refrigerant just to perform a check-up. You may soon be playing with your phone on the job – to improve your productivity!

Condenser Subcooling

What happens to the refrigerant subcooling when condenser airflow or water flow are reduced? Many people instinctively say that the subcooling would decrease if the airflow across the condenser decreased. After all, the air is what is cooling the refrigerant – if you have less of it, the refrigerant will not be cooled as well – so you might expect subcooling to decrease when airflow decreases. The only problem with this is that it is exactly backwards. In fact, decreased airflow in an air cooled condenser usually causes an increase in condenser subcooling. Remember subcooling is just telling you the difference between the condenser saturation and the liquid temperature leaving the condenser. Condenser pressure and saturation temperature both increase with reduced airflow. Most techs understand that. While the condenser saturation temperature increases a lot, the liquid temperature does not rise as quickly. The increased condenser pressure also contributes to increasing the compression ratio, so the compressor moves less refrigerant. The increased compression ratio and the increased saturation temperature cause the condenser to hold more liquid refrigerant than normal. The liquid sits longer in the condenser and has longer to be cooled below saturation temperature. Since the liquid is starting at a higher temperature compared to the air circulating over it, it tends to lose temperature faster than it normally would. All this adds up to increased subcooling. 

This is easy to verify. Start a unit, let it run a while, and check the subcooling. Now block the condenser airflow and watch the condenser pressure and liquid line temperature. You should see a big increase in the high side pressure while the liquid line temperature stays about the same or increases just a little. One caveat – don’t let the unit run too long with a blocked condenser – unless you want to run the “what happens when the compressor overheats” experiment. Monitor the compressor temperature to be on the safe side. I am not responsible for you destroying your unit while checking this out. Better to use one at school. (After asking the instructors of course)

Manual J Resources

Are you looking for materials to teach load calculations? ACCA has free excel spread sheets they call speed sheets. You can download them from their web site. They also offer a curriculum for studying Manual J8, also free from ACCA. You do have to buy either Manual J8 or Manual J8 abridged to take full advantage of these. If you are looking for load studies coverage in a text, “Fundamentals of HVACR, 2^nd ed” has a complete Unit on residential load studies. It includes examples using Manual J8 while working on a complete block load for a small house. Other Resources include Wright-Soft’s Right-J program or Elite Software’s RHVAC program. These are two very full featured commercial programs which are used a good deal in the industry. The good news is that you can download and use demo versions of them for free. Typically, there are a few limitations on the free download versions, such as not saving the files. However, you get a chance to try them out before purchase.

For teaching, I really like the ACCA Manual J Speedsheets. They are not too hard to learn, and I believe that students get a better understanding of Manual J because they do have to use the manual some to use the software. I also like the Manual D Speedsheet for ductwork. Both of these are a little limited – they are mainly for use in residential systems that are not too complex. But that is exactly where our students should be starting. We typically have our students do a block load on a small cabin and a room by room load on a 3 bedroom ranch style house. They then do a radial duct design on the cabin and an extended plenum on the ranch house. You will want to spend some time with the speedsheets before giving them to students. Although they are not difficult, there you do need to go through one a couple of times to feel completely comfortable. The instructions are in the sheets and there are ample examples on every tab. Links to the  resources mentioned are

ACCA Speedsheets

ACCA Manual J Curriculum

ACCA Educator's Page 

Wrightsoft

Elite Software  

Fundamentals of HVACR 2nd edition 

Thermostatic Expansion Valve Failures

There have been a run of TXV problems in new units stemming from a chemical used as a rust inhibitor on some of the compressor bearings in Copeland Scrolls. A reaction between the rust inhibitor and the POE oil used in the compressor causes the POE to coagulate and collect in the TXV. This appears to be an industry wide problem, not limited to a single equipment manufacturer. The chemical causes the valves to get gunked up and stick, usually resulting in a restriction at the TXV. The symptoms can look very similar to an undercharged system – very low suction pressure, low head pressure, and high superheat. Normally, the way I differentiate low charge from a restriction is by subcooling. A restriction typically has a normal to high subcooling. However, this is often not the case if the compressor in the system is a newer Copeland scroll. The Copeland scroll compressors designed for R-410A unload when the suction pressure drops below 55 psig. This is to keep them from operating at pressures which will damage the compressor. If the restriction is severe enough, the suction pressure on an R-410a system can drop below 55 psig. The compressor unloads, limiting how much refrigerant is pumped and holding down the head pressure.  You have low suction pressure, low head pressure, high superheat, and low subcooling: classic undercharge symptoms. However, adding charge does nothing unless you really go whole hog and grossly overcharge the system. Then you can build some head pressure, but it won’t fix the restriction or make the system cool. If the compressor is unloading, you can often hear it and even feel it in the piping. If you have what looks like an undercharged system with no detectable leak and adding refrigerant has no effect on the pressures, I bet you have a restriction. These days the restriction is often in the TXV. Several equipment manufacturers have service bulletins out regarding this issue. Below are links to a bulletin from Nordyne and a link to a YouTube video showing the bulleting from Emerson.

Nordyne Link

YouTube Link