All I Want for Christmas is a Final Rule

The EPA has released a new final ruling on HCFC reduction for Christmas! I know you are probably thinking that is not much of a Christmas present, but it really is. First, the HCFC allocations were due to expire, so without a new ruling spelling out HCFC allocations, all R-22 manufacturing and importing would have ceased January 1, 2010. A new ruling setting allocations of HCFCs has been released, fixing this potential train wreck. You can download a copy of the ruling and read all the details on the EPA website

Next, the details of exactly when you may and may not install “new” equipment which uses HCFC refrigerant have been clarified. You may recall that last December the EPA shocked our industry by announcing that they considered systems which are field installed and charged to be “manufactured” when the refrigeration system was complete and the final charge added. For split systems, this would be when the system is installed. Most people in our industry were well aware of the manufacturing cutoff of January 1, 2010, but we assumed the more common definition of manufacturing date: when the equipment is made in the factory. The EPA is sticking with their definition of manufacturing, but that does not mean all R-22 inventory becomes rubbish on January 1, 2010. Packaged equipment like window units, PTACS, and packaged air conditioning equipment can all be legally sold and installed as new provided it is manufactured (in the factory) prior to January 1, 2010. You are allowed to sell and install pre-charged R-22 component parts made before January 1, 2010 to replace parts in existing systems. So you may swap out condensing units, evaporator coils, or even both in an existing system. Replacing both the condensing unit and evaporator coil on an existing system is legal. Another interesting twist is that manufacturers may ship component system parts with a nitrogen holding charge instead of refrigerant. These “dry” components can then legally be assembled into a new system provided the system is then charged with reclaimed refrigerant and not virgin refrigerant. The impact of these regulations will be minimized by the fact that most manufacturers reduced or eliminated their R-22 equipment manufacturing the past few years. Contractors have also widely accepted R-410A and few still install new R-22 systems now. R-22 production will be reduced to 41.9% of the baseline production, but that will probably be enough. With no manufacturers using it and no new systems being installed, I believe that R-22 will still be available for servicing existing systems.

I do not believe replacing an existing R-22 system with a new R-22 system is really in the customer’s best interest. Why would someone want a system that uses a refrigerant which is scheduled for extinction? Also, all new high efficiency equipment uses HFC refrigerant, not R-22. We still need R-22 equipment in schools simply because our students need to know how to work on it. You cannot assume that every call will be on a system with the latest technology. In fact, you can almost assume the opposite. Our students will continue to see R-22, so we need to teach it. However, we need to teach toward the future and not stay stuck in the past. Your lab should have many pieces of equipment with HFC refrigerant, like R-410A. You should have recovery equipment and gauges manufactured specifically for R-410A. Your texts, manufacturer’s literature, and technical literature should all support the newer refrigerants. One of our focuses in Fundamentals of HVAC/R is support for new refrigerants such as R-410A. The newer refrigerants are not only covered in the refrigerants section, but throughout the book with detailed examples using R-410A. You can learn more about Fundamentals of HVAC/R at Pearson’s site.

Oh the Weather Outside is Frightful!

Oh the weather outside is frightful, and the furnace is so delightful. But since it dries out the air so, humidify, humidify, humidify! I took a few liberties with the popular holiday tune “Let It Snow” to point out how important humidification is to maintaining comfort. Being warm blooded, our bodies normally produce more heat than they need and then regulate our temperature using different cooling mechanisms. The primary cooling mechanism is evaporation of perspiration from our skin. Dry air makes us feel cooler because it accelerates the evaporation from our skin. Humid air makes us feel warmer because the evaporation process is slowed down. Heated air is drier because the air volume increases, creating more places for water molecules to fit. In the winter, the cold outside air simply cannot hold very much moisture because of its decreased volume. Take it in the house, heat it up, and it expands in volume and decreases in relative humidity. It still has the same amount of specific humidity in grains, but its relative humidity is much lower because it can now hold more water. Many people overheat their homes to compensate. Have you ever had a customer that wanted to maintain 78°F in the winter and 72°F in the summer? They are not batty, they are using temperature to compensate for poor humidity control. However, overheating only increases static electricity, dry mouth, chapped lips, and other humidity related discomfort. So it fixes one problem, feeling cold, and creates a whole bunch of other problems. Adding a humidifier to their system will make them more comfortable by addressing the real problem, humidity. It also can save money because they can maintain a lower thermostat setting and still feel comfortable. To read more about the effect of humidity on comfort, check out Unit 61 Fundamentals of Psychrometrics in Fundamentals of HVAC/R. To download an interactive pschrometric chart for free, go to http://www.handsdownsoftware.com/Downloads.htm

Comfort Science

A few years ago someone came into my office asking for my help regarding installing an air conditioning system in his house. He was going to save money by doing it himself even though he had no training and had never run a piece of duct, much less installed a complete system. However, he was confident he could do the job after a five minute discussion with me to fill in any gaps in his information. “After all”, he said, “it’s not rocket science.” I must confess that after he told me more than once “it’s not rocket science,” I had no interest in even trying to explain to him the many pitfalls ahead. He had already determined that there was really nothing to know.

Air conditioning professionals can also be guilty of devaluing installation. Because installation involves more manual labor than service, it is easy to view installation as simply manual labor. After all "it's not rocket science." Nothing could be further from the truth.

I recently had an advisory committee meeting for my program. One contractor stressed that she really wanted people who would take installation seriously. She was especially emphatic that understanding airflow and airflow measurement was crucial. Another contractor mentioned that with the increasing complexity of today’s systems, including communicating controls and variable capacity systems, installing technicians really needed to understand how the systems operate. Yet another stressed that many customers will pay a premium price for a system that is energy efficient. However, if the system is not installed correctly they will be disappointed with the results. Another committee member mentioned that an Atlanta contractor had actually increased their sales by 27% this year. They are performing energy audits and system performance analysis and making selling customers solutions to improve system efficiency and overall comfort. Their technicians are closer to scientists than unskilled laborers.

Properly sizing and installing an HVAC/R system is “comfort science.” If you want the system to perform as advertized selection and design cannot be reduced to a square footage per ton factor and a six inch flex run for every room. After the system is chosen and the duct system is designed, it still must be installed correctly. A 20-SEER split system full of non-condensables will be lucky to operate at 13 SEER. A system with an ECM blower will use even more energy than a typical PSC blower if the duct is too restrictive. Setting up and checking out a communicating, variable speed zone system requires technicians who can read, understand, and interpret technical instructions. This is why I believe it is critical to teach the science behind what we are doing. As HVAC/R becomes increasingly technical, technicians who understand how and why machines work will become invaluable. Installing today’s increasingly technical HVAC/R systems requires technicians that are trained, understand how systems operate, can read technical literature, and can take detailed system performance measurements. In short – comfort scientists!

Fundamentals of HVAC/R has an entire section dedicated to the science of HVAC/R. These units discuss the science foundation of HVAC/R in a straight forward, approachable manner and give practical HVAC/R examples of its application. Units include:

• Unit 4 Properties of Matter
• Unit 5 Types of Energy and Their Properties
• Unit 6 Temperature Measurement and conversion
• Unit 7 Thermodynamics – The Study of Heat
• Unit 8 Pressure and Vacuum

Positively Thankful

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

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

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

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

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

Carbon monoxide is an odorless, colorless gas that is highly poisonous. It is formed by the incomplete combustion of carbon based fuels, like natural gas, oil, coal, or wood. Incomplete combustion can be caused by lack of oxygen, improper mixing of the fuel and oxygen, or too low a combustion temperature. A correctly adjusted gas or fuel oil flame should produce very low levels of CO. Ideally a correctly adjusted gas or oil flame should produce no CO, but realistically, most produce at least trace amounts. Solid fuels almost always produce large amounts of CO, that is why charcoal comes with a warning that it is not to be used inside. Even people that should know better sometimes overlook the obvious. A friend of mine was conserving heat during a cold winter power outage by using his charcoal grill inside. His daughter became very ill and had to be rushed to the hospital where they correctly diagnosed her condition. This story ended well, she recovered and is doing well. Unfortunately there are many stories about CO that do not end well.

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

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

• Unit 37 Gas Fired Heating Systems
• Unit 38 Warm Air Furnaces
• Unit 40 Gas Furnace Installation, Startup, Checkout, and Operation
• Unit 41 Troubleshooting Gas Furnaces
• Unit 42 Oil Fired Heating Systems
• Unit 43 Oil Furnace and Boiler Service
• Unit 44 Residential Oil Heating Installation
• Unit 45 Troubleshooting Oil Heating Systems

There are many good web sites for more research on carbon monoxide poisoning.

A few are listed below.

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

http://www.cosafety.org/Aboutco.htm

http://www.clima-tex.com/consumer/carbonmonaction.html

http://annhyg.oxfordjournals.org/cgi/content/abstract/18/1/79

http://www.coheadquarters.com/colimits1.htm

http://www.coheadquarters.com/CarbonMonoxideHQ.com/index.html

Flue Season is Here!

No not the swine type, the furnace type! The weather is getting cold enough in many parts of the country that people are starting up their furnaces. Now is a good time to teach your students to check furnace flues during fall seasonal checks. The purpose of this article is not to discuss CO poisoning, but it deserves a mention since furnace flue problems can lead to carbon monoxide poisoning and CO poisoning shares many symptoms with influenza. One big difference is that influenza is normally accompanied by a fever and CO poisoning is not. For more information on CO poisoning check out the Carbon Monoxide Safety Organization web page.

A good place to start discussing furnace flues is to describe the four categories of vented appliances: Categories I, II, III, and IV. These categories are determined by the static pressure in the vent and the temperature of the vent gasses. For reasons of manufacturing and application limitations, Category II and III furnaces are rare. Most furnaces fall into either Category I or Category IV; 80% furnaces are category I while 90% furnaces are category IV. Category I furnaces are vented with type B gas vent. Category IV furnaces are usually vented using PVC. The combustion gas is cool enough to be safely vented through PVC and PVC is relatively easy to seal air tight.

In practical terms the vent gasses in a properly operating Category I furnace will not leak out small cracks because the vent gas pressure is less than the surrounding air. Vent gasses will generally not condense in a Category I flue because the temperature of the flue gas is considerably above dew point. Even though most 80% furnaces manufactured today have induced draft blowers, they still operate with a non-positive pressure vent because of the buoyancy of the hot combustion gas. However, the combustion gas coming from an 80% induced draft furnace is far more likely to condense in the flue than with older natural draft appliances. Oversized vents, single wall vents, masonry vents, or some combination of these can lead to condensation in the flue. Flue condensation can corrode metal vents and cause masonry vents to crack. Severe condensation can return water to the furnace and cause pre-mature heat exchanger failure. These situations most often occur when an older existing furnace is replaced with a newer, higher efficiency furnace. Even though the newer furnaces are designed for regular type B gas vent, they can not necessarily be connected to the old furnace flue. The extra heat in the combustion gas and the dilution air from the draft diverter of the older furnaces combined to make large single wall vent connectors and masonry vents work without condensation. The cooler combustion gas and lack of dilution air in the fan assisted furnaces makes their vent gas more susceptible to condensation. I have seen a single wall vent connector on an 80% induced draft furnace in a crawl space rust completely through and fall on the ground in a single year of operation. The furnace replaced a previous natural draft furnace that operated for many years without problems on the same type of vent. To prevent similar results when replacing an older furnace I recommend using only double wall vent and installing a metal flexible chimney liner when venting into a masonry chimney. An alternative to lining the masonry chimney is to vent horizontally using a power venter and not using the masonry chimney. More information on power venters is available from Field Controls

Another important step is to size the vent. The existing vent for the older natural draft furnace being replaced is often larger than is required for the 80% induced draft furnace. An oversized vent can also lead to condensation. You can download a pdf file on vent sizing from Hart & Cooley

Visual cues that furnace combustion or venting needs attention include: rust on metal vents, condensation weeping from vent joints, or carbon buildup anywhere in the vent system. Your students may run across non-condensing furnaces that were vented using a rigid plastic vent material called high temperature plastic vent, HTPV. This material has been recalled and should be replaced whenever it is found. HTPV recall If they see any of this material they should contact the furnace or vent material manufacturer or to find out what replacement vent material is recommended.

Fundamentals of HVAC/R can help your students prepare for flue season. Details on gas combustion can be found in Unit 37 Gas Fired Heating Systems. Furnace categories are discussed in Unit 38 Warm Air Furnaces. Vent sizing is discussed in Unit 40 Gas Furnace Installation, Startup, Checkout, and Operation. Gas combustion and venting problems are discussed in Unit 41 Troubleshooting Gas Furnaces.

The New 70

Many of the old timers I talk to who are still leery of R-410A want to know what the “new 70” is. They want a target number for the suction pressure of an R-410A air conditioning system. Many service technicians are in the habit of charging to a target number on the suction side. This is frequently 70 psig on R-22 systems. The saturation temperature of R-22 at 68.5 psig is 40°F and for many years the standard evaporator temperature at design conditions has been 40°F. But 70 is a nice round, easy to remember number and close enough for quickie rules of thumb. The problem is that systems seldom operate at design conditions. Another big problem is that conditions other than charge can cause low suction pressure. If a technician is only checking the suction pressure, they are not collecting enough information to recognize other system factors that can contribute to low suction pressure. A common error of inexperienced techs using the “70” method is overcharging systems that have low evaporator airflow. I have gone behind someone using the “70” method who had overcharged the system so severely the compressor stalled at startup and pegged my high side gauge past 500 psig. The customer was told that the compressor was bad. To be fair, most experienced technicians that use the “70” method understand how airflow and system operating conditions affect system pressures, they just don’t want to bother with manufacturer’s charts. They just modify the target up or down as they judge conditions affecting system pressures. These folks can usually get a system cooling; that is why they still have a job. However, the system will often not be performing optimally when they leave. Today’s customers are paying a premium for systems that are more efficient and have less environmental impact than older systems. Beginning January 2010, even the least expensive unit a customer can purchase will be non-ozone depleting and more efficient than the least expensive unit they could purchase just a few years ago. This means everybody is paying for efficiency and reduced environmental impact. However, if technicians don’t charge units properly, customers are not getting what they are paying for. Your students can be the vanguard of a new era that values professionalism. Make sure your students know how to handle new refrigerants like R-410A and know how to read and follow manufacturer’s charging charts. That will put them in a position of leadership early in their career.

Fundamentals of HVAC/R has a detailed discussion of system charging in Unit 27 Refrigerant System Evacuation and Charging. Variables affecting system pressures, common methods of determining the correct charge, and common methods of adding refrigerant are all covered. Charging is also discussed in other units including

• Unit 35 Residential Split system Air conditioning installations
• Unit 36 Troubleshooting Split System Air Conditioning
• Unit 52 Heat Pump Installation
• Unit 53 Troubleshooting Heat Pump Systems
• Unit 83 Troubleshooting Refrigeration Systems
• Unit 84 Installation Techniques
• Unit 85 Planned Maintenance
• Unit 86 Troubleshooting