Mission HVAC

Shuretape has launched an initiative to follow three students at Athens Technical College through their studies in the Air Conditioning Technology Program. To support the students, Shurtape is challenging them each to a series of missions. They complete the mission and report their findings on the Shurtape blog. They have chosen three students with different backgrounds and different ages: Matt Morris, Daniel Buth, and Josue Treo. By following these three students’ blog postings, you can gain some perspective on what it is like to be an HVAC student preparing to enter this profession. They receive a new mission every month. The best way to find out more about these three outstanding students and their mission is look at the Shurtape blog http://www.shurtape.com/blog

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.    

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! 

Caught One!

The lead story of the August 11, 2014 Air conditioning Heating and Refrigeration NEWS is “Man Gets Prison Time for Venting R-22.” In this particular case he was stealing copper – he just did not bother to recover the refrigerant first. The police literally caught him in the act, and knowing what he did was a Federal violation, reported him to the EPA. Now he is serving 31 months in prison. Truthfully, most people who steal copper or vent refrigerant are not caught. However, this case proves that you CAN be caught, and there is a substantial penalty.  Some people do the right thing because that is the way they conduct their lives. Others need some external reinforcement to avoid doing what they know they are not supposed to do.  Without penalties for breaking the rules, these folks will ignore the them. Hopefully this incident will be widely publicized so that other potential thieves in need of external reinforcement will consider another line of work. Or at the very least, steal something that does not involve venting refrigerant.

Here is a link to the story Prison Time for Venting Refrigerant

Oxy-Acetylene Torch Safety

One of my e-buddies, Dave Christensen, suggested that I write about oxy-acetylene torches. He recently bought a new torch and confessed that he read the instructions before using it. In the instructions, he noticed that the regulator settings were different from the ones he had used for years. When we teach students to use torches in school, we typically teach them the regulator settings that work for the equipment we have. I am afraid we may not always make sure students understand that torch settings are not universal. The correct regulator setting depends upon the torch manufacturer, the tip size, and the application. Torch manufacturers typically provide these settings in the instructions.

There are a few guideposts that stay the same. For example, you NEVER, NEVER, NEVER set acetylene above 15 psi. In fact, I get nervous above 10. The reason is that acetylene is unstable at pressures above 15 psi and can explode. So how does it not explode in the acetylene cylinder at 250 psig? It is dissolved in acetone liquid which is stabilized in a porous core. That is why you should never transport or use acetylene cylinders on their side – it lets the liquid run out of the cylinder into the valve area. Also, you really don’t need the oxygen above 20 psig. Many tip charts have it about half that for most applications. However, the exact settings you should use are ... in the instructions!

Another common safety issue is leaving your regulators set and just opening and closing the tank valves when you want to use the torch. This is convenient and saves time, but it is dangerous. Regulators can fail because of the sudden bump in pressure. This can cause parts to fly and high pressure gas to stream down the hoses. The last thing you should do when shutting off your torch is to adjust the regulator T handles out counterclockwise until all the spring pressure is released. When the cylinder valves are opened they should be in this position. AFTER opening the cylinder valves you can adjust the regulators to he correct pressures.

When lighting the torch, you should light the acetylene first by itself and then bring in the oxygen. Opening both the acetylene and oxygen simultaneously can cause oxygen to flow into the acetylene hose and regulator if the oxygen pressure is higher than the acetylene pressure. This can create a very dangerous situation – a mixture of fuel and oxygen under pressure in the hose and regulator. The only place we want this type of combustible mixture is in the tip.  When shutting down, reverse the process. Close the oxygen first and then the acetylene.

Torch manufacturers have some very good training material available for free. Here are some links to some good training resources.

http://training.victortechnologies.com/

http://www.harrisproductsgroup.com/en/Products/Equipment.aspx

http://uniweld.com/en/uniweld-videos

Stubby Gauges

Anyone who has ever disconnected a hose from a Schrader valve knows about the spray you get as a result. If you are taking a hose loose from the liquid line there can be quite a lot of very cold refrigerant spraying out. Many people don’t realize that the spray is usually NOT coming from the Schrader valve, but from the hose! The spray is from refrigerant that is trapped in the hose coming back out when you loosen the hose. By my calculations a standard 5 foot 1/4” hose holds about 3.5 ounces of R22 liquid. Releasing it is bad for the atmosphere, bad for the system, and bad for you if it gets on your skin. If the system was perfectly charged before you connected your gauges, it is no longer after you take them off.  If you were to connect a 5 foot hose to the liquid line of a dorm refrigerator and fill up the hose, you would essentially suck most of the charge out into your hose and gauges. Of course you would first have to install a piercing valve or two – creating potential leaks to boot.

My point is that you don’t always need to connect your gauges to every system you see – especially small critically charged systems. Even on larger systems, if you are connecting gauges just to check the system operation, consider getting a couple of “short gauges.” These are essentially a gauge mounted on just enough tube to connect it to the system. They hold a minimal amount of refrigerant, so the amount released is much less. This saves the atmosphere, is better for the system, and is way better for your fingers. Here is a link to a picture of a set of stubby gauges used in an article on ice machine service found in Contracting Business Magazine.

EPA Proposes Ban on R-404A and Other Refrigerants

You may have heard that the EPA is proposing to ban the use of some common refrigerants  I would like to give a brief overview of things you should know about this proposed ruling. First – at this stage it is still a proposal – not a ruling. Typically the way this works they publish a proposed ruling, allow us to comment on it, revise the ruling based on the comments (if they choose to), and publish the final ruling.  Since this is still a proposed ruling, you have a little time before it will take effect. Second, not all industries are affected by this ruling. Air conditioning caught a break – air conditioning systems are not covered . However, motor vehicle air conditioning IS covered. For motor vehicle air conditioning the big news is that 134a will no longer be acceptable in NEW VEHICLES beginning January 2016. A large number of zeotropes are also banned from use in new vehicles, but most of those are mainly used today as an R12 substitute. That should not have a great effect because they are only banned in NEW vehicles.

Retail refrigeration appliances and vending machines are also covered. The big news here is that R507 and R404A will be considered unacceptable for both new AND retrofit applications in retail refrigeration beginning January 2016. Retail refrigeration would include things such as display cases in grocery stores.

Four areas that are NOT covered by this proposed rule (yet) include cold storage warehouses, ice machines, refrigerated transport, and industrial process  refrigeration. However, the EPA is specifically asking for comments about the possibility of using low GWP refrigerants in these areas as well.
 “EPA requests comment on the use and viability of both low-GWP refrigerants (e.g., R-744, R-717, and HCs) and other HFC-blends (e.g., R-407A and R-407F) and the possibility of listing R-404A, R-507A, and other high-GWP blends unacceptable in any or all of these four end-uses.” I encourage you to do some of your own research into this. Here is a link to the proposed RULING. Here is a link to a FACT SHEET about the ruling. Here is a table summarizing the proposed changes to the auto air conditioning and retail refrigeration refrigerants.

Refrigerant Uses Deemed Unacceptable as of January 1, 2016
End-use	Substitute	Further Information
Retail food refrigeration (new and retrofit)	R-404A	R-404A is a blend, by weight, of 44% HFC-125, 4% HFC-134a, and 52% HFC-143a. It has a high GWP of approximately 3,920. Other substitutes are available for this endues with lower overall risk to human health and the environment.
Retail food refrigeration (new and retrofit)	R-507A	R-507A is a blend, by weight, of 50% HFC-125 and 50% HFC-143a. It has a high GWP of approximately 3,990. Other substitutes are available for this end-use with lower overall risk to human health and the environment.
Retail food refrigeration (condensing units and supermarket systems) (new)	HFC-227ea, R-407B, R-421B, R-422A, R-422C, R-422D, R-428A, R-434A	These refrigerants have GWPs ranging from 2,729 to 3,607. Other substitutes are available for this end use with lower overall risk to human health and the environment.
Retail food refrigeration (condensing units and supermarket systems) (retrofit)	R-407B, R-421B, R-422A, R-422C, R-422D, R-428A, R-434A	These refrigerants have GWPs ranging from 2,729 to 3,607. Other substitutes are available for this end use with lower overall risk to human health and the environment.
Retail food refrigeration (stand alone units only) (new only)	HFC-134a	HFC-134a has a Chemical Abstracts Service Registry Number (CAS Reg. No.) of 811-97-2 and it is also known by the name 1,1,1,2-tetrafluoropropane. HFC-134a has a relatively high GWP of 1,430. Other substitutes are available for this end use with lower overall risk to human health and the environment
Retail food refrigeration (stand alone units only) (new only)	FOR12A, FOR12B, HFC-227ea, IKON B, KDD6, R- 125/290/134a/600a (55.0/1.0/42.5/1.5), R-407A, R-407B, R-407C, R-407F, R-410A, R-410B, R-417A, R-421A, R-421B, R-422A, R-422B, R-422C, R-422D, R-424A, R-426A, R-428A, R-434A, R-437A, R-438A, RS-24 (2002 formulation), RS-44 (2003 formulation), SP34E, THR-03.	These refrigerants have GWPs ranging from approximately 550 to 3,607. Other substitutes are available for this end-use with lower overall risk to human health and the environment.
Vending machines (new and retrofit)	R-404A	R-404A is a blend, by weight, of 44% HFC-125, 4% HFC-134a, and 52% HFC-143a. It has a high GWP of approximately 3,920. Other substitutes are available for this endues with lower overall risk to human health and the environment.
Vending machines (new and retrofit)	R-507A	R-507A is a blend, by weight, of 50% HFC-125 and 50% HFC-143a. It has a high GWP of approximately 3,990. Other substitutes are available for this end-use with lower overall risk to human health and the environment.
Vending machines (new only)	HFC-134a	HFC-134a has a Chemical Abstracts Service Registry Number (CAS Reg. No.) of 811-97-2 and it is also known by the name 1,1,1,2-tetrafluoropropane. HFC-134a has a relatively high GWP of 1,430. Other substitutes are available for this end use with lower overall risk to human health and the environment
Vending machines (new only)	FOR12A, FOR12B, IKON B, KDD6, R- 125/290/134a/600a (55.0/1.0/42.5/1.5), R-407C, R-410A, R-410B, R-417A, R-421A, R-422B, R-422C, R-422D, R-426A, R-437A, R-438A, RS-24 (2002 formulation), SP34E.	These refrigerants have GWPs ranging from approximately 550 to 3,085. Other substitutes are available for this end-use with lower overall risk to human health and the environment.

Dryer Sheets In The Coil

Recently, two different techs have told me stories about finding dryer sheets used creatively in customers air conditioning systems.  When they asked their customer why there were bunches of dryer sheets stuck to the air filter, the customer said they liked the “clean, fresh scent.” Another story involved customers removing supply registers and stuffing  dryer sheets across the outlet of the register to “filter and freshen” the air. Naturally, some of these found their way to the coil where they clogged the coil and caused enough air flow restriction to freeze the system up. In all cases, dryer sheets stuffed into clever places only serve to restrict the airflow. Even if they did not, all you are accomplishing is introducing whatever chemical is on them into your system. They don’t remove odors – they just add more. Honeywell used to sell a system to do that called the “Scentrol.” Scentrols used little gel cans that looked like sterno. They system controlled how much air circulated over the can to regulate the scent. It even had a wall control. My father sold one to a customer who also bought an electronic air cleaner with an activated charcoal filter to remove smells. The customer insisted on having the Scentrol installed, even after dad explained that they were buying one machine to put smells in the air and another to take them out. Here is a link to an online forum that has a picture http://www.hvacproforums.com/threads/honeywell-scentrol.1148/

So what do you suggest to customers who want the air conditioner to improve their home’s odor? I don’t think you can buy a Scentrol anymore. First, try to find out if there are specific odors they are trying to get rid of. Finding and eliminating the source is really the best option. My brother once discovered that the kitchen sink drain leaving the disposal had never been connected on a new house in which the customers were complaining about dirty sock syndrome. If the odors are system related, look at the condition of the indoor coil and make sure there are not problems such as a leaky return in a crawl space. If they just like the idea of having a “fresh scent” system there are a number of filters that use activated charcoal to absorb odor. Just check that the pressure drop across the filter is not too high. Like the famous 1” pleated filters, some of the charcoal filters can add enough restriction to cause an airflow problem even when they are clean. Another option would be an air cleaner that uses titanium dioxide and UV light to eat up compounds that cause odors. Both Field Controls and Lennox make air cleaners that use this technology.  Now you are on the high end of the cost spectrum, but you are dealing with solid, reputable companies who sell things that work.

Check System External Static BEFORE Sealing Ducts

I recently read a thought provoking article by David Richardson in the July 7 Air Conditioning Heating and Refrigeration News. In it he argues that sealing an undersized duct system can cause problems. The system cooled BEFORE you sealed the ducts, and now that you have worked on it, the system cannot move enough air to stay operating. I know I have seen many systems with marginal ductwork that still managed to operate, even if inefficiently. The duct leaks could be allowing just enough extra air flow to keep the system operating. The combination of leaks on both the return and supply sides of the system serve to reduce the static pressure difference against which the fan must move the air. If the static pressure difference between the return and supply is already at or past the limit the manufacturer publishes for their system, sealing the ducts will increase the already high static pressure difference and push the system over the edge. This is why Mr. Richardson advises taking a reading of the total external static pressure difference BEFORE sealing the duct to avoid this trap. If it is too high, the duct system will need more attention than just sealing – it will need some duct modifications as well. Better to know before you do the job. What is too high? I don’t like to see anything higher than 0.8” wc – that is usually the top end on most residential systems. Most residential systems will operate comfortably around 0.5” wc. Some will go all the way to 1” wc, but at a cost. With ECM fan motors you are burning electricity to shove air through restrictive ductwork. With PSC blowers you lose airflow at high external static pressures. This costs electricity in another way. The suction pressure drops, the compression ratio increases, and system capacity decreases – causing extended run times and inefficient operation.

Digital Gauge Roundup

Just a few years ago there were only a few choices if you were looking for a gauge manifold with true digital gauges. Now there are at least 16 different options available. There are also at least two new options that are very different from the others. The most expensive have a retail price in the $1,000 range, but there are at least four offerings in the $300 range. Nearly all of these are billed as Digital System Analyzers because they do more than measure pressure. All of them also measure temperature, many also measure vacuum, and all will perform calculations such as superheat and subcooling. Even though they are still a bit expensive, by the time you compare them to the cost of a set of gauges, thermocouple thermometer, and vacuum gauge they start to look a lot more affordable. If you don’t currently own a vacuum gauge and digital thermometer (not an infrared thermometer) you can consider the cost of a digital system analyzer as part of the cost of acquiring tools your are SUPPOSED TO HAVE! A vacuum gauge will cost around $200 and a thermocouple thermometer and clamp $150. When you add that $350 to around $100 for the least expensive analog gauge set that is good enough to use, you are looking at $450.

The least expensive analyzers have a standard 2 valve manifold and no vacuum gauge while the more expensive models typically have a better 4-valve manifold and a vacuum gauge. At least two models feature wireless data connectivity as well. Be aware that the prices you see usually do not include hoses. A good set of hoses can cost $100 if you are getting three 1/4” charging hoses and one 3/8” vacuum hose. If you are getting large hoses, such as Appion 3/8” or 1/2” hoses, they can cost $100 a hose. So when shopping, make sure you are getting an analyzer, a manifold, and hoses - unless of course you are going to use one or more of those pieces you already own.

The gauges that read vacuum typically switch from displaying pressure to displaying microns of vacuum at some point during the evacuation. On the subject of vacuum, one problem with having a vacuum gauge built into the gauges is that the gauges are not the best place to be checking the system vacuum. However, I have used a Fieldpiece set like this and have been generally pleased with the result. So far, our Fieldpiece SMAN4 set has held up well under student use. Yellow Jacket has a built in vacuum gauge in theirs, but a separate vacuum sensor so you can still measure the vacuum at the unit but use the built in vacuum gauge in the analyzer.

Hilmor has a digital gauge set that has both analog like displays and a digital readout. It looks a bit more like a traditional gauge set but still gives you all the digital goodies. I find the Hilmor gauges the easiest to use – no screens to scroll through and all the information on display all the time. Imperial has a brand new i-manifold which has no display! It uses Bluetooth to connect with your smart phone or tablet and uses that as the display. With the display being part of an app, it can do a lot more things and be more easily updated. You can download the app for free and use it by entering the temperatures and pressures. Pretty shrewd move! Once you get hooked on the app you will want the manifold to go with it, like the story “If You Give a Mouse a Cookie.” If you are not conversant with that reference to classic literature, you probably don’t have kids. Finally, my friends at Appion are coming out with digital high side, compound, and vacuum gauges that connect to the side port of the valve core tool they sell. No manifold needed!

I have uploaded a table of available digital system analyzers with a summary of the features of each. The file, “Digital_Gauges,” is in the Survival Kit on my Google Drive. I gleaned these from information available on the internet. The Appion gauges are not included because they are not released yet, but I saw them in March at the instructor’s conference in Baltimore. The address for the survival kit is https://drive.google.com/#folders/0B0i1Mw3czgHrLTN4M1p1LVh6Yms

Defining Amps Without Ohm's Law

Here is a pretty basic question : What are amperes (amps for short)? Many folks will tell you using Ohm’s Law. However, defining volts, ohms, and amps in terms of each other is circular logic – it does not really explain what they are – only their relationship to each other. Amperes have a definition that does not involve Ohm’s Law. Amps are a measure of electrical current flow. The flow part is important. This means that time is involved. Amps are not really a quantity, but a rate. One amp is the flow of one coulomb of electrical charge per second. Note that the coulomb is the quantity and the ampere is the rate. Compared to gallons and gallons per minute (GPM), Coulombs are like gallons and amps are like gallons per minute (GPM). A gallon is a quantity – a specific amount of water. A gallon per minute (GPM) is that quantity of water moving in a minute. To have GPM, the water has to be moving and there is a time involved. Amps are the same way: the electric current must be moving and there is time involved. So what about Ohm’s Law? Well it is great for explaining the relationship of volts, amps, and ohms. I just find it useful to explain the concept of amps as a measure of current flow first.

Sensible and Latent Cooling

When you look at manufacturer’s tables showing the capacity of their units, you will notice terms such as latent capacity, sensible capacity, or total capacity. The sensible capacity expresses the unit’s ability to reduce the air temperature. In most conditions, only part of the system cooling capacity goes into reducing the air temperature. The name comes from the idea that this change in heat can be sensed, or measured with a thermometer. I have had students tell me they remember it because it makes “sense,” and is therefore “sensible.” The word latent means hidden. Latent cooling capacity is used to take water out of the air. It is latent, or hidden, because you cannot measure it through temperature change. Latent changes involve a change of state. The water in the air is changing state from a vapor to a liquid. To accomplish this, the heat that went into the water to vaporize it must be removed. A system’s capacity is not fixed – it changes with the temperature, relative humidity, and volume of the air blowing across the evaporator coil. System capacity used for latent cooling is not available for sensible cooling. So as you increase the percentage of latent cooling a system performs, you decrease its sensible capacity. Here in the southeast, latent cooling is just about as important as sensible cooling. We MUST remove water from the air to be comfortable. In other parts of the country, such as the southwest, taking water out of the air may be undesirable. We can have some control over this by controlling the airflow. As a general rule, as you increase airflow across the evaporator coil, you increase sensible cooling and decrease latent cooling. In a humid area it makes sense to set the system airflow to a level that will increase latent cooling. For example, 350 CFM per ton rather than 400 CFM per ton. In a dry area, you may want to increase airflow to minimize latent cooling. For example, 450 CFM per ton. Although most systems will operate at 400 CFM per ton with no mechanical problems, that may not be the ideal airflow for your application.

Are You Ready for R-32?

Are you ready for R-32? R-32 is one of the two components found in R-410A. Some major air conditioning manufacturers have been studying R-32 for use by itself. Why? Primarily because R-410A has a high global warming potential (2088) – even higher than R-22 which it replaced. On the other hand, R-32 has a much lower GWP of 675. R-32 is an HFC compound, not a blend. So it has none of the problems of vapor charging, fractionation, and glide found in the zeotropes. It is also a very efficient refrigerant and operates at pressures similar to R-410A.  So what is the catch? Flammability.

R-32 has a 2L flammability rating. This means that it will burn, but it will not explode. There is no flash point. It will burn when ignited, but it self extinguishes when the ignition source is removed. Still, it burns. Safety in design and handling must be a major priority when handling flammable refrigerants. As global warming potential becomes more of an issue, the industry will be moving toward flammable refrigerants. In general, the more flammable a refrigerant is, the lower its GWP. Most non-flammable refrigerants all tend to have a high GWP while extremely flammable refrigerants such as propane, R-290, have a very low GWP.  (Note that this is not always the case. CO2 has the lowest GWP of 1 and it is not flammable at all.)

Daikin, the world’s largest air conditioning manufacturer, is already producing R-32 systems for sale in other parts of the world. Danfoss is also studying R-32. For more information on R-32, check out these links.

Danfoss

Daikin

AIRAH

Cut it Out!

The safest way to remove a refrigeration component is to cut it out, rather than de-brazing it. In the case of filter driers you don’t want to heat the drier and drive moisture and contaminants back into the system. With all components, there is the hazard of fire caused by vaporizing the refrigeration oil in the system. Heating the joint enough to render all the brazing material molten increases the temperature and pressure. When you pull the part loose, a stream of gasses comes out and is ignited by the torch flames and/or the red metal. Even if the refrigerant is non-flammable, the oil will burn. People have been seriously injured when large amounts of flaming oil discharged on them after de-brazing a refrigeration component. The most serious cases involved people de-brazing a system that was still fully charged. Accidentally cutting a line on a charged system would not be nearly as hazardous as de-brazing one.

In addition to the flame hazard of the oil, all fluorinated refrigerants create nasty, toxic fumes when exposed to flames even if they don’t burn. If you have ever gotten a strong snort of this stuff you know it is an experience to be avoided.

One more reason to be cautious now is the presence of so many refrigerant blends with small quantities of hydrocarbons in them. Although the quantity of hydrocarbons is small, the hydrocarbons can concentrate in the compressor oil when charged into a system with mineral oil. Even after recovery, there can still be volatile hydrocarbons in the compressor oil. You heat it to de-braze the compressor, and a flammable gas comes out when you pull the pipe loose. I have heard one story where the technician was de-brazing a compressor and was engulfed in a ball of flames for a short period of time after pulling the line out of the compressor. It was a brief flash fire that burned off his eyebrows and gave him a sunburn, nothing too serious – but definitely scary. The refrigerant was an R22 replacement rated A1/A1. Also, consider that with so many replacement refrigerants you really don’t know exactly what is in the system. Although the highly flammable R22 replacement refrigerants are illegal, they are widely available on the internet and they are sold to anyone with a credit card. Just on the off chance that the system you are working on was topped off with propane, you should avoid de-brazing. Make sure and purge the system with nitrogen before brazing the new compressor in. Not only will you avoid oxides inside the lines, you might also avoid fires in the area you are working in. I believe refrigerants with some degree of flammability will become more common. To be safe, we need to start treating all systems as if the refrigerant could burn. So the next time you have to remove a refrigeration component – CUT IT OUT!

Do You Own a Backup Wrench?

I am often talking about new technology and recent trends in HVACR on this blog. Today I would like to discuss a rather old piece of technology – the backup wrench. If you work in mechanical trades and you don’t own a backup wrench, then you are my intended audience! A backup wrench is not used to reverse anything, and it does not have left handed threads. Backup wrenches are often specified by manufacturers when installing mechanical fittings, yet most techs do not have any wrenches in their tool box named a backup wrench. I have sometimes reminded students to use a backup wrench only to be told that they only have some open end wrenches and a couple of adjustable jaw wrenches – no backup wrenches. By now you hopefully have figured out I am pulling your leg. “Backup” does not describe a particular wrench, but how the wrench is used. The wrench is backing up the fixed part, keeping it from turning. When tightening a nut or fitting onto a valve or coil, you are often instructed to use a backup wrench. Many units have stickers on them stating: “use a backup wrench.” The backup wrench holds the fixed part in place, keeping it from twisting when the nut is tightened. Otherwise, it is quite possible to turn the fixed part once the nut is tight. This twists the copper tubing connected to the valve or coil connection, causing leaks and restrictions. Unfortunately, this is a common occurrence in school. Students try to “fix” a leaky flare with a 12” wrench and a hefty turn. Repairing the damage can be pretty tricky, and it is definitely time consuming. If you look carefully, most male flare connections have flats on them – that is where the backup wrench goes. One wrench goes on the fixed part and another goes on the part that is turning. That way you can control exactly what gets turned. So the next time you go to tighten a flare on a valve or coil, make sure to use a backup wrench. If you don’t have a backup wrench, send me $50 and I will send you one with instructions for using it.

Appearance Counts!

I recently attended a meeting with contractors and instructors. We are looking for a way to help local contractors hire, develop and retain the technicians they need. More than one contractor said that lack of technicians was hindering their company’s growth potential. Contractors were looking for a way to pump more lifeblood into our industry. The instructors in the meeting were trying to find out what  we could do to more effectively meet their needs. This involved trying to identify the most crucial aspects that seem to be missing from much of today’s prospective talent. The first thing mentioned was personal appearance. As one contractor put it “if I can’t send you to my grandmother’s house, I can’t hire you!” They discussed job applicants with body piercings, tattoos, even applicants wearing spiky dog collars! It may be narrow minded and prejudicial to assume someone wearing a spiky dog collar is not trustworthy, but I believe much of the general public would feel uneasy about letting someone into their house who was wearing a spiky dog collar. Service Techs ARE the company as far as the customer is concerned. The impression they make has a lot to do with the trust the customer places in them. If the customer does not trust them, they will be hard pressed to do their job – the customer will be suspicious of anything they say or do. If you want to pursue a career dealing with the public, you need to carefully consider the impact any body art may have on people who meet you. Often, body art almost seems to scream “I WANT TO SHOCK YOU!” Even companies that are desperate for help don’t want that association with their company. Here is a short list of things that will improve your chances of getting past the first interview.
 

• Before going to the interview cover up any tattoos you can and remove any extraneous metal objects from your body that might be seen during the interview. 
• Don’t wear a T-shirt with an obnoxious logo – wear a shirt with a collar. 
• Turn your phone off before going in.  
• Don’t drop the F bomb in every sentence – in fact, don’t curse at all. If you are used to throwing one or two expletives in every sentence you had better practice talking at home for a while. Speech becomes habit. Try going the whole day without cursing the day before the interview.
• Look the interviewer in the eyes when you talk – don’t look at the floor or up at the ceiling.
• Smile –nobody wants to work around a grouch.
• Before the interview you should study HVACR so you know how to talk intelligently about the field you are pursuing.

Understanding Pressure Gauge Specifications.

Pressure gauges have many specifications which technicians should understand when selecting a gauge, including range, resolution, accuracy, proof pressure, and burst pressure.

The range is the lowest to highest reading on the gauge. It is important that the range of a gauge fit the pressures for which it will be used. You want a gauge able to read the highest pressure you might encounter, but you don’t want the top reading much higher than that. This is because accuracy is stated as a percentage of full scale. A gauge with an accuracy of 1% and a top reading of 300 psig has a possible error of 3 psi. If you make the top reading 600 psig, now the possible error becomes 6 psi. If the pressures you will be reading only go up to 250 psig, expanding the top pressure reading just makes the error larger.

Resolution is the smallest indication the gauge can display. A gauge that can display in tenths of a pound has a resolution of 0.1 psi. This is not the same as the accuracy. Just because a gauge CAN display in tenths of a pound does not mean the reading is accurate to tenths of a pound. However, having a small resolution does make the gauge more useful for precise readings than another gauge with the same accuracy and top scale. For example, there are both analog and digital gauges with the same accuracy, but an analog gauge with a scale of 0 – 500 psig cannot have a resolution in tenths of a pound – there is just not enough space. A digital gauge with the same accuracy and top reading has no problem displaying in tenths of a pound.

Accuracy is stated as plus or minus a percentage of full scale. Full scale is the highest reading on the gauge. To determine how far off a gauge can be and still be within specifications, multiply the percentage accuracy times the top reading. For example, a gauge with 1% accuracy and a top reading of 500 psig would have an accuracy of plus or minus 5 psi. Note that the accuracy is plus or minus a percentage of full scale, NOT, a percentage of the reading. For example, a reading of 400 psig could indicate a pressure anywhere from 395 psig to 405 psig. This is not too bad at 400 psig, where 5 psi only represents 1.25% of the actual reading. However, plus or minus 5 psi becomes a problem at lower readings. A reading of 25 psig could indicate a pressure anywhere from 20 psig to 30 psig.  Now 5 psi represents 20% of the actual reading. For accuracy reasons, you don’t want the top reading on a gauge to be any higher than it has to be to get the job done.

Temperature compensation is an important aspect of accuracy in digital gauges. The accuracy of the sensors used in digital gauges changes with temperature. A gauge that specifies an accuracy at a single temperature is only that accurate at that temperature. It will be less accurate at other temperatures. A temperature compensated gauge maintains its accuracy over a wider range of temperatures. The most accurate digital gauges will be temperature compensated.

Proof pressure is the highest pressure the gauge can withstand without damaging the sensor. This is typically considerably higher than the highest reading.

Burst pressure is the pressure at which something on the gauge physically breaks. It is higher than the proof pressure. Gauges should be selected with proof pressures and burst pressures considerably higher than the highest pressure you would expect to encounter. A gauge which would be perfectly acceptable for use with systems using R-134a might not be acceptable for use on systems using R-410a.

A Lab Gone Wrong Sometimes Teaches More

Sometimes adversity is the best teacher. Recently one of our first semester students learned more than he bargained for when he had multiple issues with his lab. The lab was to recover the refrigerant from a packaged unit, evacuate the system, and weigh the charge back in. The recovery process went well, but things got off track during the evacuation. The system would not pull down low enough for the vacuum gauge to register. After waiting a while, he decided he must have a leak, so he disassembled his evacuation setup and began to put nitrogen in the system. The leak showed right away – it was on the stem of the Schrader valve. It may have been created while he was connecting and disconnecting hoses. He brazed up the leak, reassembled his evacuation setup, and evacuated the system down to 250 microns. However, when he closed the valves on the core tools the vacuum started to rise. I told him a little rise is normal because the pressure back in the recesses of the system is a little higher than right at the point where you are pulling out the gas. However, it continued to rise past 1000 and kept going. At which point he decided he must have another leak. Once again, he disassembled his evacuation setup and charged the system with nitrogen. When he took off the vacuum gauge, he noticed that the rubber O-ring was missing. Most likely, that was his second leak. He left a note on the system stating the nitrogen pressure and ambient temperature so he can check it on Monday after a weekend of sitting. If the temperature changes, he will have an opportunity to use the gas laws to determine what the holding pressure should be. The lab was really intended for practice in refrigerant recovery, evacuation, and charging. He will get that, but he also receives the bonus of seeing first-hand the effect a leak can have on system evacuation. This also illustrates the value of leak testing and using vacuum gauges. Without the vacuum gauge he would have charged a leaky system and a good bit of the refrigerant would be gone in a few days. Vacuum gauges don’t cost time, they save it. Using a vacuum gauge is the only way of knowing when you have a vacuum and when you don’t. If you can’t pull a deep vacuum, you need to find the problem. The time you save by ignoring the problem will be far outweighed by the time it will cost chasing down the problem later.

Sure Thing in VEGAS!

The upcoming 2014 Educators & Trainers Conference & Expo in Las Vegas is a SURE THING! You can’t lose! You won’t find this many different training sessions anywhere else, especially not for this price. The conference is from March 31 – April 2. There are over 40 sessions with top name speakers from all over the country. A big plus to a national training conference comes from networking with other instructors from all around the country. With several hundred instructors at the conference, you will most likely learn something from fellow attendees during discussions in the hall or lunch. Sharing ideas and offering support and encouragement are vital to the long term health of our industry. If you live within driving distance, this conference is definitely a no-brainer.

I know that times are tough and getting funding and permission to go is difficult. When presenting the idea to your school administrators be sure to forward a copy of the program for the conference. Be sure to note the large number of educational sessions. There are literally more sessions than you will have time to attend. There may also be topics of interest to school administrators – such as Getting Started in Hybrid Instruction, or Program Accreditation. There are also opportunities to get free equipment. At one of these conferences a few years ago I learned about the Appion program to donate recovery machines and vacuum pumps to schools. That alone would cover the cost of your trip. If all those arguments don’t work, just tell them that I will be speaking. I am sure that will seal the deal. I hope to see you all there!
You can read the details here http://www.hvacexcellence.org/nhetc/Faq.aspx

Be Part of the Solution

Quick question. What credential can you possess that is more valuable to your employer and your career than professional certification? Answer: customer referrals. Although you may think you work for ABC Heating & Cooling, the truth is, you work for Mrs. Smith. If Mrs. Smith is not satisfied with your work, your attitude, your appearance, or your personality your company will hear about it. On the other hand, if Mrs. Smith calls in or writes and comments on the great job you did, how professional you are, or how pleased she was with your service, that is more valuable than almost any other asset you bring to the company. If Mrs. Smith asks for you by name when she calls, that is money in the bank for you. I have known customers who will follow a service tech when they switch companies because they want that particular technician to work on their systems. You want the customer to feel good about their decision to call you and your company.

My father always urged me to “be part of the solution, not part of the problem.” I can remember being at someone’s house working with dad on a piece of builder grade equipment that someone else put in. I remarked out load about the cheap brand furnace they had and was quickly and forcefully reprimanded. “NEVER insult the customer.” In dad’s eyes our job was to fix a mistake they had already made. He built his business by being part of the solution. People remember who helped them out of a jam and offered solutions to their problems.

Always try to keep the conversation positive. If you have identified problems, present solutions. Never belittle the customer for a poor decision they made. Instead, offer a better way or a way out of the problem. Never badmouth previous companies and techs. Instead, focus on your solutions. If the issue is a safety concern, you should certainly explain the risk, but offer a solution. In short, focus on solutions, not problems. Your job is to help the customer solve problems, not point out all their shortcomings. Dwelling on mistakes of the past, no matter whose they are, only leaves the customer with a negative feeling. Worse, they associate you with bad news and don’t want to see you again. Focusing on solutions and remaining positive makes the customer feel better. They associate you with good news and solutions. If you do this, I guarantee you customers will start asking for you by name. There is no better job security than having customers calling in and asking specifically for you.