Be Part of the Solution

My father lost his battle with cancer early on the morning of December 21, 2015. When someone dies there begins a very busy period where family and friends come together to take care of all the details associated with final arrangements as well as to figure out how everyone whose lives were closely knitted to the deceased will regroup and continue with the business of living. In a peculiar twist, a house that has just been overcome by the shadow of death overflows with life. A neighbor called in the midst of this activity. I answered the phone and was mistaken for dad. The neighbor did not know dad had died, and I did not correct her. Instead, I just listened because I could tell she was upset and needed help. The mail carrier had already been by her house and had not come up to the house to bring the mail. She had two letters she needed to mail and feared that she had missed her chance. She is legally blind, and so tries to void walking down to the street. I explained that I was not dad, but his son. However, I said that I would be glad to take her letters and see that they were mailed today. I walked down to the neighbor’s house, got the letters, found the mail carrier, and handed over the letters. You see, dad’s neighbors had gotten used to turning to him when they needed a solution. One of dad’s mantras was “be part of the solution, not part of the problem.” I was glad to help dad be part of the solution one more time.  

Funky Flames

Funky flame patterns may be an indication of a dirty or restricted secondary heat exchanger in 90% furnaces. Most furnaces today use draft inducer blowers which draw the vent gasses through the heat exchanger. In the case of furnaces with efficiencies of 90% or greater, there are two heat exchangers – a primary and a secondary or recuperative heat exchanger. The secondary heat exchanger condenses water out of the flue gas. Most secondary heat exchangers look something like a tube and fin coil made out of stainless steel. Many have turbuators inserted into the tubes to increase the heat transfer by making the gasses swirl as they pass through the tubes (see photo). Flue gasses could never make it through without the induced draft blower drawing them through.

If the water does not drain properly out of the secondary heat exchanger, flue gases cannot travel though easily, and the combustion gases back up. This causes the flue gas created by the flames to find another exit – usually out the front where the gas and air entered. The errant flue gasses disturb the flames creating yellow coloring, dancing, extinguishing and relighting, or rolling out of the combustion chamber. The resulting flames often create a lot of carbon, which can further clog up the heat exchanger.



If you see these symptoms BEFORE the indoor blower is energized, you should first check to see that the induced draft blower is operating and that it is actually producing a draft. Sometimes the blower wheel comes apart or slips off the shaft – causing the motor to turn without actually moving any air. Next, you may want to inspect the secondary heat exchanger for obstruction. This varies between units, but most often you will need to remove the draft inducer to see the secondary heat exchanger. If the secondary heat exchanger is filled with water – you need to solve the drainage problem.

If it is clogged with black soot, the secondary heat exchanger will need to be changed. If that is the case, you will also need to look for the cause of the soot. Double check the orifice and operating manifold gas pressure. An oversized orifice or incorrect manifold pressure can cause soot. If the furnace is located more than 1000 feet above sea level, remember that it must be de-rated – which can mean a lower manifold pressure and/or a smaller orifice. Check with the manufacturer for orifice and manifold pressure recommendations. If the furnace uses sealed combustion (combustion air coming in through its own pipe) check to see that the combustion air pipe is not restricted. Birds and rodents are common problems. If the flame pattern is fine up until the indoor blower comes on, and THEN the flames get wacky, you probably have a cracked primary heat exchanger. In this case, the primary heat exchanger definitely needs to be changed.

A Nutty Furnace Problem

A common fault in condensing furnaces is a draft switch shutting down the furnaces. Before changing that switch, check to see if the switch is just doing its job. Most draft safety switches are open before the draft inducer fan starts. The ignition board looks to see that the switch is open before starting the inducer blower. If the pressure switch is closed before the draft inducer starts, the process stops right there and the board will flash a diagnostic code or report a fault in the case of communicating systems. Disconnect the tubing and wires going to the draft switch and check resistance between the two electrical connections, usually labeled “common” and “NO” for normally open. You should read infinity (OL). If you get any reading besides OL, the switch is bad. Assuming the switch reads open (OL), you want to check to see if the switch is closing, and at what pressure.  Put a tee and short piece of tubing in line with the tubing connected to the draft safety switch and connect a magnehelic or digital manometer to the branch on the tee. Remove the wires connected to the pressure switch and use alligator clips to connect meter leads to the switch connects and set the meter to read continuity. A meter with a continuity beeper works best so you don’t have to watch the meter. Start the furnace and observe the pressure reading when the meter beeps. You are trying to determine the pressure where the switch closes. Once you have that, compare it to the rating on the switch to see if the switch is opening at the right pressure. The correct pressure is usually on the pressure switch.    This can be pretty tricky because it happens quickly. Connecting the pressure switch to a tool that provides a controlled vacuum works better, but involves another tool.  There are electronic vacuum tools as well as simple rubber bulbs that can be used to produce a vacuum. If the pressure switch does not close and the pressure reading shows a vacuum of at least the pressure switch rating, the switch is bad. If the switch does not close but the pressure is not at the rating, the problem is that you don’t have enough draft. This can be caused by leaking vacuum hoses, bad inducer fan motors, loose or rusted induced blower wheels, or stopped up vents. Recently I learned about a condensing furnace whose vent was stopped up with acorns and plants. Squirrels were hiding acorns in the vent, which was discharging horizontally out of the house. When the acorns got wet from the furnace vent gasses they started to sprout, so the vent was stopped with plants and acorns. One way to prevent this would be to add a large mesh screen over the vent outlet. However, many manufacturers recommend against using a screen over the vent. They are worried that water will condense on the screen and freeze, causing an obstruction. In areas with a lot of squirrels, you may still want to add a large mesh screen (1/4” between wires) over the vent pipe because it is easier to remove an obstruction on the vent outlet than down inside the vent pipe. Removing the squirrels also works, but is easier said than done in some areas. There are more squirrels than people in my neighborhood.  

Practicing Responsible Behavior

Irresponsible behavior can cost you an opportunity for the job you really want. A bad driving record can affect your employability as an HVACR tech. Whether installation or service, it is common for HVACR Technicians to drive company trucks. The company pays dearly for insurance to cover these trucks and drivers. The first thing many employers do when considering a new tech is to turn their name into the insurance company for an investigation. The insurance company looks up your driving record for the past seven years. Too many problems and the insurance company will refuse to insure you. Obviously you won’t get the job if the insurance company won’t insure you. I know a local contractor who has had a particularly frustrating experience with this. They hired three people who the insurance company would not insure. Particularly troublesome are DUI/DWI and multiple speeding tickets – especially if the speed amounts are 20 mph or more over the limit. Before you complain that this is unfair, remember these are actions you can control. It is logical for the insurance company to avoid obvious risks. As for the HVACR Company, they really must be insured. Further, the behavior and driving record of their employees can affect their rates – which are already quite high.

While we are discussing controllable behaviors, you should know that many companies require drug testing these days. Again, this goes back to avoiding risk. So even though a number of areas are making some recreational drug use effectively legal, this can keep you from being hired. A local company told me that they have a six week hiring process. At the beginning of the interviews they inform the job applicants that they will have to take a drug test if they make it through all the interviews. Half of the people who clear the interview process fail the drug test. This means they could not stay clean for six weeks even though they were warned up front. So do yourself a favor: don’t use recreational drugs; if you drink, don’t drive; slow down when you drive; and follow the rules of the road. You will most definitely will be expected to do these things AFTER you get a job, so you might as well start practicing now.

Bobby Towe: A True Craftsman

It is a little harder to write my annual thanksgiving article this year. A friend and great HVAC mechanic just died – finally losing his long running battle with cancer. His name is Bobby Towe. Bobby and his brother Bennie were a large part of what made my family’s business, Stanfield Air Systems, the type of business it was and continues to be: a place where craftsmen work for friends. Bobby’s brother, Bennie started working with dad soon after dad had opened his business. Bennie was working in a local cotton mill and was looking for a more rewarding job with better working conditions. He knew nothing about HVAC when he started with dad, but he grew to be dad’s right hand man having learned both the installation and service side of the business. Bennie had only been working with dad for about a year when he brought Bobby by. Bennie wanted his brother Bobby to have the same opportunity that he had. Bobby became the best sheet metal man around. He was a craftsman. Bobby cared about what he made, and I am certain, enjoyed creating. You may not regard plenums, transitions, and offsets as creative works of art, but Bobby treated each one he made as if it were going into an art gallery. After he retired from daily HVAC work he took up woodworking and carpentry. Not surprisingly, he became very good. He made furniture, shelves, and cabinets  - he still needed to create. He made a beautiful shelf system for my dad to hold his CD and tape collection. I always think of Bobby whenever I see it. That shelf represents how much dad meant to Bobby and how thankful he was to have the opportunity to work with dad.  This thanksgiving I am grateful to have known a true craftsman, Bobby Towe.  

CO Safety and the HVACR Tech

There is more to carbon monoxide safety than leaky furnace heat exchangers. Venting problems may actually cause more CO safety issues than leaky heat exchangers. I am not suggesting that you overlook the importance of checking furnace heat exchangers for leaks, but rather that you expand your CO safety horizons a bit. I want to talk about CO safety concerning the technician – you. A combustion appliance operating in an unsafe condition can spill vent gasses containing CO out into the room where it is operating. This can create a safety hazard for technicians going into that area to service the furnace. You should carry a CO detector that displays the CO level in the area you are working in. If the ambient CO goes above 50 ppm – you should leave. 50 ppm is the OSHA standard for the maximum allowable concentration for an 8 hour work day.

Ray Wohlfarth recently published an article in the October 2015 issue of Plumbing & Mechanical magazine in which he discusses a story of an electrician being overcome by CO fumes. The electrician was working in a mechanical room on something completely different than the boilers, but the boilers were in that room and not operating properly. When the electrician failed to report back to the school administration, the secretary was sent to see what was taking him. She found him passed out on the floor – ran and called 911 to get emergency medical help. This undoubtedly saved his life. Suppose that had been a service technician working on a furnace with nobody home? By the time someone found the tech – it would probably be too late.

Before you go to a big box store to get a home CO detector, consider that they are typically built to UL 2034 standards, which allows 15 minutes before alarming at levels above 400 ppm. This is just not fast enough in the case of high levels. The UL standard is weighted to prevent false alarms, but this also means that a UL listed device can fail to alarm at dangerous levels until it is really too late. Plus, typically these do not show what the CO level is. Kidde, a primary manufacturer of these types of CO monitors, points out that their devices are for continuous monitoring – not short term detection.

Single gas, battery operated CO detectors which display the CO level are available for $100 - $150. Alternately, you could use the CO setting on your combustion analyzer. If you don’t have a combustion analyzer, you could put that $150 you would normally spend on a single gas CO detector towards one of the lower cost $500 combustion analyzers. You will be doing both yourself and your customers a favor.

Residential Combustion Analyzers

To measure combustion efficiency you need a tool that can measure either the oxygen or CO2 content of the combustion gasses. For many years, an hour glass shaped bubbler containing a fluid that absorbs CO2 or O2 was used. They are difficult to find these days. They have been replaced by electronic instruments. These use an electro-chemical reaction in an oxygen sensor to measure the O2 content in the flue gases. They use thermistors to read the flue gas temperature and ambient temperature, so they have all the information that need to calculate and display combustion efficiency. They use this information to display CO2 %, O2 %, combustion efficiency, % excess air, flue gas temperature, and net stack temperature. Most offer other measurements as well. Some of the more common additional features include:

• CO ppm – to read the CO in the flue gas

• CO ppm air free – to calculate the CO ppm after removing the excess air

• Draft pressure – to insure you actually have a draft

• Differential draft pressure – to insure the draft pressure is lower than the room pressure

• NOX – to comply with NOX regulations in areas that restrict furnace NOX emissions

• Printer – to print out reports from results

• Computer Connectivity – to import data from analyzer to programs on your computer

Prices vary a good bit. From just over $500 for no-frills analyzers intended for residential work, to several thousand for commercial instruments. Certificates of NIST traceability often cost more.  Most combustion analyzers use electro-chemical sensors. These have a limited life because the chemicals in them are used up as they work. Typical replacement time is every one to two years. Some are user replaceable, and others require sending in the tool for the sensors to be replaced. This will typically cost $200 - $300. The table below compares several of the lower priced models which are aimed at the residential market.

	Bacharach Intech	Testo 310	UEI C75	E Instruments BTU 900
O2	yes	yes	yes	yes
CO2	yes	yes	yes	yes
Efficiency	yes	yes	yes	yes
Excess Air	yes	yes	yes	yes
CO	yes	yes	yes	yes
Air Free CO	yes	yes	no	yes
Draft pressure	no	yes	no	yes
Differential Pressure	no	no	no	yes
NOX	no	no	no	Can upgrade
Printer	Available Extra Cost	Available Extra Cost	Available Extra Cost	Available Extra Cost
Computer Connectivity	no	no	No	USB & Bluetooth
Field replaceable sensor	yes	no	no	yes
Fuels	6	5	5	10
Warranty	2 years	2 years	3 years	2 year
Approximate Street Price	$520	$600	$500	$1000

Combustion Efficiency

Fall tune up season is here. A seasonal check on a gas or oil furnace should include a check of the combustion process. To do a good job you really need to measure the combustion efficiency. To measure combustion efficiency you need to take two temperature readings and one flue gas reading.  The temperatures are the flue gas temperature and the ambient temperature around the unit. You subtract the ambient temperature from the flue gas temperature to get what is called the net stack temperature. The flue gas reading can be either CO2 or O2.Generally oxygen is preferred. For a gas furnace, perfect stoichiometric combustion produces 12% CO2 in the flue gas. The CO2 percentage drops off if the process is either too rich (too much fuel) or too lean (too much air). At the perfect stoichiometric point the O2 will still be 0% because all of it is being used in the combustion process. As excess air is introduced into the process, the O2 begins to rise due to the oxygen content in the air that was not used in the combustion process. Excess air is introduced to insure complete combustion. Note that complete combustion is not the same as perfect combustion. In perfect (stoichiometric) combustion, ALL the fuel and ALL the oxygen are used up, producing ONLY carbon dioxide and water. In complete combustion, all the fuel is used up, but not necessarily all the oxygen. Lack of combustion air produces incomplete combustion. Incomplete combustion leaves some unburned carbon and carbon monoxide. Excess air is introduced on purpose to prevent the production of soot and CO in the flue gas. The figure below shows the relationship of CO2, CO, O2 , and excess air. Next week we will discuss some of the ore practical aspects of measuring the combustion process.

Ride All the Rides!

Ride All the Rides!

Undoubtedly, many of you will spent  some time this past summer at an amusement park, water park, or other recreational establishment. Many parks now have a single price for admission that lets you ride all the rides as many times as you like. After paying the price of admission, most folks try to ride as many rides as possible to get their money’s worth. I can remember planning out my day at Disney World so that I would make the most of my time. I can see many of you smiling because you have done the same thing and planned a manic day at a pricey amusement park so you would get your money’s worth. I read recently that a year’s pass to Disneyland was now over $1000. I would have to be riding stuff every day if I paid that. So here is my question. Why are we so intent on getting our money’s worth at an amusement park, but beg to be cheated in education? When you pay your tuition for the semester, you are paying to ride all the rides. Every lecture, every lab, every online assignment, and every test you already paid for when you paid tuition. Chances are, your tuition was more than $1000 and it was not for an entire year. If you think tuition and fees are high, why would you not take full advantage of all that you paid for? Try reading the assignments more than once. It does not cost any more, and you get more out of the assignment. When you miss a lecture, lab, or assignment you are cheating yourself. Not only are you not taking advantage of the services you have paid for, but you are also limiting your earning potential later on. My brother Richard has a saying “work hard at school, or work harder all your life.” People with jobs which require less education and skill work harder and longer for far less money. HVACR is a very performance based industry. If you can’t perform, your earning potential suffers. Your diploma may get you in the door, but it won’t keep your job. HVACR is also a very technical field. To excel, you need to understand the systems and how they operate. Sure, without a lot of training you can get a job holding the other end of heavy things or running to get tools for other people. But without training or education, you won’t advance much past that point. And of course, the folks holding the other end of the furnace don’t get paid the big bucks. Attending school is not the only way to learn your trade. There are many ways to educate yourself, but the easiest and fastest is to go to school. Throw yourself into your studies. Attend all the lectures, read all the assignments, and do all the labs. Ride all the rides!

Duct Cleaning Cuts Allergies

Occasionally I have a "guest speaker" provide the weekly article. This week, Gary Arena provides a some insight into the benefits of duct cleaning. Enjoy.

Allergies
Allergies can be a serious problem for someone’s overall health. The high concentration of pollen has been at an all-time high this summer, and overall allergies are increasing each year. Sensitivities to mold, mildew, dust and dirt can make everyday life a struggle. When a home air adaption is supplying air that contains these allergens, life can be quite miserable.

Benefits of Air Duct Cleaning and HVAC Restoration:
By removing this containment from a home air adaption, the effect is greatly reduced. Clean, healthy, circulating air is a must for those highly sensitive people. It is not unusual for a person to realize immediate relief upon completing a cleaning of a home heating, ventilating, and air conditioning adaption.

 
Here are the top 9 triggers that contribute to asthma attacks and allergy symptoms:
1. Dust Mites

2. Mold

3. Second-Hand Smoke

4. Cockroaches and Pests

5. Pet Dander and Hair

6. Wood Smoke (solid burning fuels)

7. Outdoor Air Pollution

8. Nitrogen Dioxide (from gas burning appliances and utilities)

9. Chemical Irritants

When dirt and debris are removed from ductwork, the fans and motors that power a furnace no longer need to work as hard to distribute air. Advising people to routinely get their air ducts serviced and inspected is important. Not only does this properly maintain a building, but it keeps the quality of indoor air as pure as possible!

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Written by Gary Arena from DUCTZ of Greater Lancaster and York Cities. Gary is the owner of the professional air duct cleaning company in central PA and is proud to serve a locally and family-owned franchise.

Managing Large Numbers of Lab Students

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

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

What is superheat?
What measurements are required?
How did you arrive at the current superheat?
What readings are necessary to use the manufacturer’s superheat charging chart?
What does the system charging chart say the superheat should be?
Compare the manufacturer’s specification to the actual operating superheat?


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

Labor Day

As we celebrate this Labor Day I am reminded of the many Americans who don’t want a day off, they are looking for a day on. Your job provides you with more than the financial means to support yourself. For most of us, we are identified by our profession. One of the first things people ask when meeting is “what do you do?” Having regular earned income also gives us a way to be more in control of our destiny. With a predictable source of income, you can better manage your life. This is crucial for people wanting to improve their lot in life.

I truly believe all our political leaders want to help. We would all like for everyone seeking employment to find it. There have been many attempts by government at all levels to pass legislation that would stimulate the economy and create jobs. Many of these programs focus on training people for jobs of the future. The problem is that it is very difficult to accurately predict the future and create truly new jobs, particularly in new and emerging technologies. I believe we would have more success investing our time and money training people for jobs that already exist, particularly in fields where industry growth exceeds the available workforce. HVACR is one such industry.

Jobs are available now for skilled HVACR technicians. Money spent in technical education prepares students for real jobs that we know exist, not jobs that we wished exist. Further, if you want new emerging technologies – train folks for commercial refrigeration. Commercial refrigeration is undergoing a major transformation involving new energy-smart, earth-wise technologies.  So training people for a career in commercial refrigeration IS training for jobs of the future. The lack of qualified technicians is limiting HAVCR contractor’s growth, which limits the growth of the nation’s economy. Again, these job opportunities exist NOW.

Preparing people for a real job that pays real money makes them a contributing taxpayer. This means that the government gets the money back. Some HVACR students will be successful enough to start their own business. There are several in the Athens area who started as students at Athens Tech. One relatively small business with five employees can gross $1,000,000. That generates tax revenue of $150,000 at 15%. If those five employees are trained at Athens Tech, the cost of their training is less than one year’s tax revenue. Not all students will generate that kind of return, but even a student earning $12 an hour will likely pay back the cost of training in less than five years. For people who already have a job in HVACR, education makes them more productive and earns them more money. Increased productivity means a better bottom line for the government – more income to tax. It is not necessary to start new programs with new administrative costs; there are already programs and institutions in place with proven track records of training workers for skilled trades. All we have to do is support them.    

What Flavor is Your CO2 System?

If you work in any phase of refrigeration, you undoubtedly have heard about the emergence of CO2 refrigeration systems in commercial refrigeration. I had the pleasure of touring the HillPhoenix Refrigeration plant in Conyers today, and I was impressed by both the number and variety of CO2 systems they are currently building. They had Cascade systems, Trans-critical systems, Glycol systems and Booster Systems all using CO2. These are distinctly different approaches to working with CO2.

The transcritical has probably received the most press. It derives its name from the fact that the high side operates above the critical point while the low side operates below the critical point. The name indicates that the system operates on either side, or across, the critical point of the refrigerant. The critical point is the pressure and temperature at which the refrigerant can no longer condense to a liquid. So the “condenser” is really just a gas cooler. The refrigerant does not condense to a liquid until AFTER the pressure is dropped. The critical temperature of CO2 is 88°F, so any time the high side temperature rises above 88°F, the refrigerant will not condense. The pressures are bit higher than you might be used to – over 1200 psig, so not just any compressor and piping will do. However, in a way, the transcritical systems are a bit simpler than the other flavors.

Cascade systems use two complete refrigeration systems – one system’s job is really to cool the condenser of the other system. If you keep the CO2 cold enough, say 40°F, the pressures are not that high. However, to have a 40° condenser requires a system whose evaporator is in that same temperature range and whose condenser is at the normal operating temperature for an air cooled condenser. This system typically uses HFC refrigerant. So you have a heat exchanger and an HFC system to keep the CO2 system cool. This allows wider range of compressors because the CO2 compressors are not operating at 1200 psig. However, the system operating with the normal temperature condenser (80°F – 100°F) will have a refrigerant OTHER than CO2.

And then there are the booster systems. The booster systems incorporate both low and medium temperature racks into a single unit. The low temp CO2 compressors pump into the suction of the medium temp CO2 compressors, which operates at transcritical temperatures and pressures. This way the low temp compressors don’t have to be heavy duty transcritical compressors, just the medium temp compressors. The system uses only CO2, no HFC refrigerant is required, as in a cascade system.

There are also glycol systems, where the refrigeration system cools glycol, which is pumped through the store to the cases. This reduces the amount of refrigerant in the system and reduces leaks by reducing the amount of piping, fittings, and braze joints. What became apparent in my visit was that there are many ways to solve the same problem, and you can expect to see different solutions at different locations. It also is apparent that in commercial refrigeration, CO2 is here to stay and HFCs are on their way out.      

OSHA Updates Confined Space Safety Rules

Contractors who work in crawl spaces and attics may find the latest confined space regulations ... confining! Until recently, residential contractors rarely had to worry about confined space regulations. Now they will need to address confined space regulations on most jobs - both installation and service. OSHA just made changes to the confined spaces rules which will affect everyone that works in residential attics and crawl spaces. Considering that a large amount of residential HVAC equipment is installed in an attic or crawl space, these changes will affect residential HVAC contractors. A confined space is now defined as

1.         Large enough to get your body in
2.         Limited means for getting in and out
3.         Not designed for continuous occupancy

The employer is responsible for providing a competent person to inspect all confined spaces before work begins. This person is looking for any other hazards which can make the confined space more dangerous, such as toxic fumes, low oxygen, electrical hazard, fall hazard, or extreme temperature. (Note this is only a partial list.) If the confined space has any additional hazards it becomes a permitted confined space. Workers can only enter a permitted confined space for the purposes listed on the permit under the conditions and restrictions listed on the permit. A hazard warning must be posted at the entry to a permitted confined space and a permit issued that lists all the details regarding work in that particular confined space. There must be an attendant posted outside a permitted confined space any time a worker is in the space. There are many more regulations. This is honestly only the tip of the iceberg. Suffice it to say, you want to avoid having to declare the confined space a permit required confined space. 

You are allowed to remove hazards to accomplish this. For example, a typical attic with no floor is a permitted confined space based on the fall hazard. If you put boards down for the workers to walk on you remove that hazard, and it no longer requires a permit. Similarly, an electrical hazard can be removed by turning off all power to the confined space. If a confined space has no additional hazards, then you can use what OSHA refers to as an alternate procedure. For this, the competent person must determine that no additional hazards exist, or that they have been removed. The space needs continual positive ventilation while work is being performed. However, the permit and the attendant are not required. Note that this still requires a competent person to inspect the pace BEFORE work begins.

Some logical questions come to mind, such as

Who is the competent person?

The competent person can be one or more of your employees who have been trained to recognize hazards in confined spaces and can use test equipment to test for oxygen level, combustible gasses, or toxic gasses. In the event of an incident, they will be asked to clearly tell OSHA what procedures they used identifying the risks involved with the space. 

Where do I get the permit?

For confined spaces requiring a permit, your company generates the permit – not some government agency. The purpose of the permit is to clearly communicate the conditions under which the space may be entered and who may enter.

When does this go into effect?

The new rules will start being enforced on October 2, 2015.

Where can I read more about this? (Trust me, you NEED to even if you don’t WANT to)

 Final Ruling

Training Webinar Video

Enfocement Date 

OSHA Confined Space Page

Legionnaires Cooling Tower Article

I just saw this article in the NEWS discussing Legionnaires and cooling towers - very good info. Since this ws the subject of my most recent post I thought I would share this important information.

http://www.achrnews.com/articles/130330-legionnaires-disease-sickens-108-in-new-york

Defeating Legionnaires Disease

Legionnaires disease is back in the news. It is caused by the legionella bacteria. The disease is most commonly spread by dirty cooling towers. The legionella bacteria grows in dirty tower water, and is transported to the surrounding area in the mist droplets leaving the tower. When someone breathes in water mist contaminated with legionella, they may contract a pneumonia that can kill people in a few days. 

The good news is that this is relatively easy to prevent by simply keeping the cooling towers clean.  Normal tower water maintenance will prevent the legionella from growing in the tower in the first place. If you have ever had a back yard wading pool for the kids, you know how quickly water left outside can develop slime – literally in a couple of days. Now think how quickly stuff can grow in water that is being heated, as in a cooling tower. Cooling towers need constant maintenance to stay clean. 

This can be done by testing the water weekly and adding chemicals as needed, or by using an automated chemical feed system. Even with an automated system, the water should be checked monthly to insure everything is working properly. Every building that uses a cooling tower should have someone on staff or contracted to keep an eye on the water condition. Some chemical salesmen will perform this service in exchange for buying all the chemicals from them. Obviously, the cost of their service is built into the price of the chemicals. In general, you want to maintain a slightly acidic ph to discourage calcium deposits and critter growth. 

Another reason to keep your cooling tower clean is that the same water circulating through the tower is also circulating through your condenser. A coating of green slime inside your condenser will insulate the condenser from the water passing through, reducing system efficiency. This translates into higher operating cost. You are not saving money by skipping cooling tower maintenance, you are spending it on increased system operating cost. Here are a few links with more details on cooling tower maintenance.

Aqua Chem

Chem-Aqua

SPX

BAC

NALCO

  

Send Superman Over to Fix my Unit

I have noticed something that is happening now in many companies - employees are often asked to be superhuman because of the amount of work to be done and the chronic short handed situation many companies find themselves in. This can lead to looking the other way as employees do things they should not do while trying to do the impossible. I had a recent graduate complain that the company he worked for scheduled him to do an installation by himself which he did not complete until 11:30 PM. He did not even get to the job until after his normal scheduled quitting time. He had a company meeting at 7:00 AM the next morning, which he made. However, in the 7.5 hours between completing the job and returning to work he had to get home, sleep, and return to work. His truck still had the old equipment in it from the night before. He was reprimanded for having a messy truck - a violation of company policy. In my mind, the problem started when he was scheduled to do the impossible. I have heard more than one story like this. Another student told me his wife went from asking when he was going to get a job to asking when he was coming home. Upon graduating, he had responsibility for the large rack refrigeration systems in 15 grocery stores spread across 2 states. He was not left entirely on his own – they gave him a cell phone. Trying to service these far flung, complicated systems which he was just learning about had led to 60 and 70 hour weeks. Students are glad to have the job, but they are often covered up in work before they even have a year in the field. When they demonstrate that they can perform, they are rewarded with more work. I believe as an industry we need to allow new techs a bit of breathing room and time to develop into the techs we want them to be. That means we have to still provide time for education and training, time to sleep, and time to de-compress a bit. The fact that so much responsibility is being shouldered by brand new techs shows our great need. This provides opportunity for people who are looking for a rewarding career which provides the income needed for a good standard of living.  The danger we face in pushing the most promising too hard is that we could literally run our best new prospects out of the trade.  

How Does an Air Conditioner Cabinet Become Energized?

The last two weeks I have been talking about electrical safety. Specifically, discussing the electrical hazard of an energized system cabinet. This week I would like to discuss ways that the cabinet of a system can become energized. First, for a cabinet to have a voltage other than ground, the cabinet is either not grounded, or the ground has failed. Failure to properly ground a metal cabinet is the first condition that sets up the electrical hazard. But another mistake or failed component is required to actually energize the cabinet. Some are obvious – such as a loose energized wire touching the cabinet. Others are less obvious, such as a grounded electric motor. If a motor is grounded (not shorted or open) and the equipment cabinet in which the motor is mounted is not grounded, when the motor is energized the cabinet will also become energized. Motors can sometimes be grounded and still operate. So you touch an operating unit and get shocked. Another failure that can energize a cabinet is a broken or missing insulator on heat strips. Most heat strips have one side that is wired hot all the time. If the ceramic insulators break and allow the strips to contact the frame holding them, the cabinet can become energized.

A sneaky way for a cabinet to be energized is to wire a 110 volt device into a 230 volt unit using one leg and ground. Basically, current will be going through ground anytime the 110 volt device operates. This alone won’t cause an energized case. But if the ground between the unit and the panel breaks or just gets a bad connection, now there will be a voltage between the case and the actual ground – and the case will be energized. To avoid this, don’t wire 110 volt devices this way. You either need a separate neutral AND a cabinet ground (4 wires), or you need a 230 – 110 transformer. This is why newer electric dryers have 4 prong plugs: two for the 230 volt hot legs, one for neutral for the motor, and one for a cabinet ground.

So here are a few simple rules to help you avoid creating an electrical hazard:

1. All metal cabinets and pipes should be grounded
2. Ground wires should never be used as part of an operating circuit.
3. When equipment has both 230 volt and 110 volt loads, the equipment either requires a neutral wire AND a separate ground wire, or a 230 volt to 110 volt transformer.

Basic Electrical Safety Tips

In light of the tragic story I posted last week, I thought an article on electrical safety would be appropriate. Here are a few things we ALL should do while working on units:

Assume all units you work on are dangerous
When you inspect hundreds of units and most are safe, it is easy to assume the equipment you will be working on is safe. Don’t assume units are safe, assume the opposite. When approaching a unit, particularly one that you don’t know anything about, assume it is dangerous.

Test BEFORE you Touch
Carry a non-contact voltage detector with you at all times. Test all disconnects and units with the non-contact voltage detector BEFORE touching ANYTHING. While you may go your entire career without ever seeing an energized case or disconnect, they do occur and it only takes a few seconds to test.

All Units and Power tools SHOULD BE GROUNDED
Everything that operates on electricity should have a ground wire. The purpose of the safety ground is to provide a good path for power should electricity contact the exterior metal parts. The idea is for the ground wire to be a better path then you are. The only exceptions are double insulated tools with non-conductive cases.

You should NOT be grounded
Try to avoid grounding yourself. If at all possible, don’t lean on grounded equipment and don’t sit or stand on wet ground or pavement. The idea is to make yourself a poor path. Wearing shoes with thick rubber soles helps.

If possible, turn the power off before working on a unit
Don’t do any more live work than necessary. If you can perform the service or maintenance with the power turned off to the unit, turn the power off. Obviously this is not always possible. For example, the power must be on and operating to check the system charge.

Use only Category III or IV electric meters on HVAC Systems
That “free” meter from El Cheapo Freight is not safe to use on an air conditioning system. You have no assurance that it can withstand voltage surges. Remember, when using an electrical meter the meter quality is what separates you from the electricity you are testing – that includes the leads. They should also be rated as Category III or IV.

Always Use a Fuse Puller to Change Cartridge Fuses
Channellocks, Vise grips, and pliers are NOT fuse pullers. That bit of rubber on the grip is NOT a very good electrical insulator.

NEVER change a fuse with the circuit still energized
Removing or inserting a fuse with the circuit energized can create an arc flash. An arc flash is an electrical fireball which can hurt you even if you are not touching any energized surface.

Tech Electrocuted Changing an Air Filter

Last week I received this heart wrenching e-mail from a friend and colleague.

“Carter, I am writing you this in hope that you will pass this on to everyone.  Last week I lost a great student and a friend. He was a student that every Instructor dreams of. He was smart and eager to work hard and make a career in our field of HVAC/R.  He was only 22 years old with a wife and an 8 month old little girl. His death has really hit me hard as his instructor.  He worked for an A/C company nearby.  While working on a heat pump service call, he had been in the attic and outside to check the equipment, then he headed under the house to change the air filter for the customer. Upon touching the air handler cabinet he became locked and grounded by a wire that was shorted to the air handler’s metal cabinet.  He was wet from sweat, from being in the attic as well as outside in our hot humid air. He was LOCKED to the air handler. After some 15 minutes the home owner called him. When he did not answer, the owner went under and found him and was able to knock him off the unit and freed him. The owner then dragged him out and started CPR. EMS arrived and continued CPR on the way to the Medical Center, where medical staff also continued CPR, but a doctor pronounced him dead. Funeral services will be held tomorrow.

 I believe every class needs to tell every student and warn them of this. He was just changing an air filter, not working on the electric wiring. I know he never would have thought of being shocked by just touching the cabinet. We have all done this thousands of times, not thinking about getting shocked. TURN OFF ALL POWER before doing anything on any unit.”

How many times have you touched a unit before checking to see if the case was energized? I cannot count how many times I have done this. THIS TECH WAS JUST CHANGING A FILTER. Before touching any electrical disconnect or unit ALWAYS check with a non-contact voltage detector to make sure the cabinet is not energized. And when you work on a unit for any reason, check to make sure that it is properly grounded before you leave. Properly grounding a unit can save someone's life. It is rare for a unit cabinet to be energized – but it does happen and the results can be tragic.

Checking Thermal Expansion Valves

If you work on air conditioners you have heard about the thermostatic expansion valve problem be-deviling the industry right now. A relatively small detail in the manufacturing of a widely used compressor has caused massive problems throughout the industry. For many years the best advice regarding service on TXVs was to leave them alone. They very rarely gave problems, and messing with them was more likely to cause a problem than solve one. Unfortunately, TXV problems have become very common now.

Valves manufactured by all suppliers are sticking due to a chemical reaction to a rust inhibitor that was used on one part inside scroll compressors. Most of the time these valves will underfeed. A system with a valve that is clogged with goo will operate with a low suction pressure, a somewhat low high side pressure, and a high superheat. It can look like an undercharge. However, an undercharged system will have low or no subcooling while a properly charged system with a clogged valve will have a normal to high subcooling. The subcooling is really the key to telling the difference between an undercharged system and an underfeeding valve. If you suspect a clogged valve, be sure to check for other refrigerant restrictions – such as a clogged filter drier. Of course if you change the valve, you will also want to change the filter.

A valve that has lost its bulb charge will also underfeed, but these normally are drastic – with the low side pulling down close to 0 psig. Valves can lose their charge from improper installation. If the bulb is attached to the suction line near where the suction line is brazed in and you don’t protect it from heat, the bulb pressure can pop the bulb charge.

Overfeeding valves are normally due to misapplication or poor installation. A system with an overfeeding valve will have a high suction pressure, a low superheat, and a low subcooling. If you see this, check the bulb installation. Make sure it is making good contact with the suction line and is well insulated. Also, make sure the external equalizer comes off the top of the suction line, not the bottom.

Unfortunately it is no longer true that expansion valves rarely mess up. However, checking the valve installation and system subcooling may save you a bunch of time and trouble. It takes far less time to check system subcooling, superheat, and the valve installation than it does to change a valve.    

Stay Hydrated and Cool

When it gets really hot, evaporation of sweat is all that stands between you and heat exhaustion. That is really your ace in the hole. The body perspires and the sweat evaporates to cool you off. When you are working in a hot environment you sweat a great deal – and that is good. However, it is important to replace the water. That is why you should have lots of water available and drink water continually while working.

Weather conditions can play a big part as well. A relative humidity over 60% (pretty much all summer in Georgia) slows the evaporation process, increasing the likelihood of heat exhaustion. When the heat index exceeds 90, you need to be careful. When it exceeds 100, you need to be extra careful. Besides hydration, stay out of direct sun and seek cool shelter whenever possible. Time spent in attics should be limited and preferably only in the early morning or evening.
  
Failure to drink enough water can lead to dehydration. Failure to stay hydrated and cool can lead to heat exhaustion, which can be dangerous. If you continue to ignore your body’s warning signals, heat stroke can occur, which is a medical emergency. You are no help to anybody passed out somewhere. If you are thirsty and really tired – TAKE A BREAK AND DRINK SOME WATER! Finally, note that we are drinking water; NOT beer or caffeinated soft drinks. Symptoms of dehydration, heat exhaustion, and heat stroke are listed below.

Symptoms of dehydration include:
• fatigue
• loss of appetite
• flushed skin
• heat intolerance
• light-headedness
• dark-colored urine
• dry cough  

Symptoms of heat exhaustion include:
• Confusion
• Dark-colored urine (a sign of dehydration)
• Dizziness
• Fainting
• Fatigue
• Headache
• Muscle or abdominal cramps
• Nausea, vomiting, or diarrhea
• Pale skin
• Profuse sweating
• Rapid heartbeat

Symptoms of heat stroke include:
• Throbbing headache
• Dizziness and light-headedness
• LACK OF SWEATING DESPITE THE HEAT
• Red, hot, and dry skin
• Muscle weakness or cramps
• Nausea and vomiting
• Rapid heartbeat, which may be either strong or weak
• Rapid, shallow breathing
• Confusion, disorientation, or staggering
• SEIZURES
• UNCONSCIOUSNESS