Friday, September 23, 2016

HFCs not Going Anywhere

HFCs are not going away any time soon. I am sure you have all hear about the push to reduce or eliminate HFC refrigerants because of their global warming potential. This past weekend at Comfortech 2016 I sat in on a very informative session by Rob Yost on refrigerants. One big point was that low GWP replacement candidates for R410A are all rated at 2 or 2L for flammability. The reason is pretty straight forward. To be non-flammable a chemical must be relatively stable. However, that stability means it lasts longer in the atmosphere, which increases its global warming potential. In other words, low flammability and low global warming potential are somewhat opposites in terms of chemical properties.

The newest low GWP blends being developed are actually blends of both HFOs and HFCs. The highest pressure HFO developed at this time is very similar in pressure to 134a. Obviously that won’t replace 410A. However, mixing it with some higher pressure HFC refrigerants yields a much lower global warming potential than 410A at working pressures that are similar to 410A. However, this mixture will be flammable.

The current building codes in the US don’t allow flammable refrigerants inside buildings in most circumstances, so none of the refrigerants presently being studied can be used under the current building codes. The next revision for building codes is due out in 2018. However, the window for incorporating exceptions for lower flammability refrigerants into the 2018 code has already passed – and no exceptions or conditions for the use of 2L flammable refrigerants are in the upcoming 2018 code. That makes 2021 the closest date that flammable refrigerants could possibly be used inside buildings. Even though that is only a little over four years from now, we can be reasonably sure that no mass extinction of HFC refrigerants will occur any time soon.

Before we transition out of 410A to something else, the issue of using lower flammability refrigerants inside buildings will have to be addressed, and even then, it is likely that HFC refrigerants will be some of the components in the next generation of refrigerants.

Friday, September 16, 2016

Are You Keeping Up?

Technology is changing the HVACR industry so quickly that many techs get vertigo from the dizzying changes. It is tempting to try and “opt out” of the technological revolution and stick to the old familiar technologies you are comfortable with. However, your lack of participation will not slow the train, you will simply be left behind.

Before heat pumps were common in the southeast, I remember many techs declaring that they would not work on heat pumps. Today, any tech in Georgia who does not work on heat pumps does not work very much. I remember another time an older tech  telling a story of how he retrofitted a system with a stack control and threw away that electronic junk. So the customer ended up paying a lot to downgrade their system because the tech did not understand it. Worse, it did not work well afterwards.

I know many techs today are leery of communicating control systems, variable refrigerant flow systems, electronically controlled compressor motors, and WiFi thermostats – just to name a few things. These things are not going to go away. Customers like them. They like the energy efficiency and convenience these products bring. If you don’t sell and service them, someone else will. The only logical course of action is to educate yourself on the emerging technologies found in the HVACR industry. This is a lifelong process. This year is not the same as last year, and there will be more to learn next year. I am older than most practicing HVACR techs, but I do not long for the “good old days.” I am too busy having fun with the new toys, there is just so much I need to learn.

Sunday, September 4, 2016

Primary and Secondary Drain Connections

Have you ever wondered why evaporator coils often have several drain connections? It is not because the manufacturer had extra PVC drain plugs they needed to use. Most coils have both primary and secondary drain connections. Sometimes they have more than one set for convenience, and sometimes they have multiple sets because the coil can be positioned more than one way. It is important to recognize the difference between a primary and secondary drain connection and pipe them correctly.

The secondary drain provides an outlet for the water in case the primary gets plugged up. Since the secondary connection is a backup drain, it is located slightly higher than the primary connection. Sometimes this is done using an internal dam which forces water to go through the primary drain unless it is plugged up.
Primary drain on the right and secondary drain on the left.
Notice the internal dam on the secondary drain connection.

Most manufacturers recommend that the primary drain be trapped, but the secondary is typically not trapped. The secondary and primary should not run to the same drain line. If the drain line gets plugged up and both drain connections run to it, there is really no point in having a secondary drain connection. Often, the secondary drain line runs  very short distance to an overflow drain pan or a condensate pump.

Another way to utilize the secondary drain connection is to install a condensate overflow switch on the secondary drain connection so that the system shuts down if water builds up to that level. I like that because the customer knows there is a problem and calls for a correction. If the secondary drain handles the water without incident it might not be noticed until it stops up as well.

Overflow switch connected to secondary drain connection on the left.

I saw a system this summer which was several years old and had never been piped correctly. The primary and secondary drain connections had been swapped. The primary drain was piped to an overflow drain pan under the unit  and the secondary drain was connected to the actual condensate drain line which was completely dry and clean. The overflow pan was full of brown slime, and the drain to that overflow pan had stopped up and the water was now overflowing into the ceiling. The difference in the two drain connections was obvious – the secondary drain connection was located higher. But maybe not so obvious to the installer. Just know that there is a reason for the two connections: one is for your primary drain and the other is to avert disaster. If you get them confused you are creating a future problem.

Friday, August 26, 2016

Keep Your Cool

This week I am passing along a tip contributed by a reader, Mike Lilley. He keeps cool by wearing a cooling vest. After doing a little research I found three types of vests for sale: one that circulates air, some that use evaporation, and some that use phase change gel. For attic work I think we can rule out the air vest because it works by circulating ambient air through the vest. In dry heat the evaporative vests should work well, especially outside. However, in an attic in the southeast, I think their performance would not be enough to keep you cool. Mike said that the workers at his company use cooling vests with phase-change gel packs.

The gel packs are similar to the blue-ice packs you might use for your cooler, with one big difference. This gel freezes and melts at 58°F. Remember that the temperature of a substance stays the same as it changes state. This is an important concept in making air conditioning work. This gel stays at 58°F until all of it has melted, and 58° is comfortable, as opposed to keeping a 0°F gel pack next to your body. Further, you can freeze the removable gel packs in a refrigerator or in a cooler with ice. A couple of users commented that it is important to keep the packs flat during the freezing process. Otherwise, the hard, lumpy gel packs make the vest uncomfortable. Here is a link to learn more about these cooling vests. I must tell you that I have not personally used one – yet. But is certainly sounds like a cool idea.

Here are a few links to learn more about cooling vests.

Saturday, August 20, 2016

Attic and Crawlspace Safety

In the last post I talked about a tech succumbing to the heat in an attic. Since the service business is about solving problems, not simply presenting them, I have been looking for solutions to tech safety. Bill Spohn of TruTechTools contacted me and offered a solution to prevent heat exhaustion and heat stroke. His company caries a line on skin patches called “HOTDOTS” that change color from black to yellow if a person starts to overheat. Each patch is a one-use patch good for one day. They come in pack of 6 for about $!6. So you can protect yourself from overheating for $16 a week – not bad. Here is a link

His company also carries a full line of atmospheric gas safety monitors which can check for things such as oxygen and carbon monoxide. Here is a link to those

If you are working on combustion equipment you really should have an atmospheric CO detector with you to insure the space you are working in does not have a dangerous buildup of CO. I would not trust the inexpensive detectors you buy in big box stores. They often have a long delay before alarming, even at levels that can be dangerous.  You need something that displays the CO level so you can test the space when you first enter without relying on an alarm.

A combustible gas detector is also advisable. You don’t want to enter a space that has a buildup of combustible gas. In the old days of halide torches I narrowly avoided being a statistic of an explosion caused by a gas leak. I was going to enter a crawl space to check for a refrigerant leak with a halide torch. I waited to light the torch until I actually got under the house, which probably saved my life. When I approached the crawl space door I smelled gas, so I did not light the torch. The odd thing was that there was no gas equipment under that part of the house. I followed my nose across the yard to a large LP tank with a bad leak where the line came out of the regulator. The LP being heavier than air had drifted downhill 50 feet across the yard and collected in the crawl space. I fixed the leaking flare and told the home owner what I had found. They said they had just received a delivery the previous day. Had I not paid attention to my combustible gas detector (my nose) there might not have been a “Fundamentals of HVACR” because one of the authors would have perished decades before. It is always a good idea to test the spaces you plan to enter. To be in a position to help anybody else you must first insure your own safety.

Wednesday, August 10, 2016

Heat Can Kill

When you think about the dangers of working on air conditioning equipment, you probably think about working with electricity, refrigerant, and torches. We often overlook a more obvious danger: the weather. The reason we have a job is because it is either hot or cold. A recent tragedy in Lubbock Texas highlights the dangers of working in attics in the summer. An HVAC worker was found unconscious in an attic and subsequently died. Here is a link to the local area news about the incident. Lubbock Tragedy

It is very important to be aware of the danger that hot and cold extremes can pose to workers. One of the most important aspects of safety when working in the heat is to keep hydrated – drink lots of water – and drink often. Evaporation of sweat is your body’s last available cooling mechanism. It is very effective provided that you keep the flow of water into your body. 

Air movement helps by accelerating the evaporation of the sweat. If possible, set up some type of fan to help move air in the attic space. I have known mechanics to disconnect a few duct runs and run the air conditioner to keep the attic cool. Of course this only works if the unit is working. 

Another way to avoid life threatening consequences of working in hot attics in the summer is to work early – preferably before noon. If someone really wants their AC working, they won’t mind letting you start work at 7:00 AM.

You must monitor your body’s reaction to the heat. If it is hot and you are NOT sweating, you should get out of the attic and hydrate. When you are hot, sweating is good. If you are experiencing a rapid pulse and muscle cramps and feel dizzy, you most likely are experiencing heat exhaustion. You should get out of the hot area, cool off and hydrate. If you have these symptoms and then develop a headache and have stopped sweating, you may be the victim of heat stroke – which is life threatening. You should get out of the heat, hydrate, and call 911.

The key is not to get to that point. When you work in the heat you must take breaks to hydrate and cool off. I recall a changeout where we worked all day – a lot of the day in the attic. We were swapping both the blower coil and condensing unit and repairing some ducts in the attic. It was 95 degrees outside and the house had a black roof with no shade. By the end of the day we were only working in 30 minute shifts and resting and drinking for 30 minutes. We would drink at least a quart of water every time we came out of the attic. Our clothes were as wet as if we had jumped in a pool. Honestly, I don’t think I could do that today. Don’t ignore what your body is telling you. If you start feeling bad while working in the heat – get to a cool place and hydrate. 

Friday, July 29, 2016

Regional Efficiency Reporting Rules

Right in the middle of the hottest and busiest summer in years the government is helping us by adding some more regulations and paperwork. The good news is that you probably already keep the records they are requiring. The Energy Efficiency and Renewable Energy Office (EERE) has just issued their final ruling on enforcement of the regional energy efficiency standards. The ruling requires equipment manufacturers, distributors, and contractors to keep records of the equipment they sell. It also requires that split systems be matched, and makes a distinction between uncased coils used as part of a complete system installation and those used as a replacement part.

The law on which this ruling is based is not new. It is Title III of the Energy Policy and Conservation Act of 1975. This specific ruling is new. It is a follow-up to the Regional Efficiency Standards. Although the regional efficiency standards have in been in place now since January 1, 2015, the details regarding enforcement are new.

What Equipment is covered by this ruling?
The Energy Policy and Conservation Act defines a “central air conditioner” as a “product . . . which . . . is a heat pump or a cooling only unit” and refers to all central air conditioners as one “product.” So when they say air conditioner, they are including heat pumps. Split system air conditioning and heat pump condensing units, cased coils, uncased coils installed as part of a new installation, packaged air conditioning and heat pump systems are all covered by this ruling.  NOT covered by this ruling are furnaces and uncased coils installed as replacement parts.

Who Must Keep Records?
Equipment manufacturers, distributors, and contractors must all keep records. However, the information you are required to keep depends upon which of these you are and what specific equipment is involved.

For every condensing unit, indoor unit and packaged unit installation, contractors must keep the following information for four years:

  • Manufacturer
  • Model Number
  • Serial Number (NOT required for indoor units including blower coils, cased coils, and uncased coils installed as part of a new installation)
  • Installation Location including the street address, city, state and zip code
  • Installation Date
  • Party from whom the unit was purchased, including the seller’s name, address and phone#

I expect most contractors already do record all the items on this list. Most manufacturers will want this information for warranty purposes. If you plan to service the equipment for the customer, you certainly want to know things like the model number, serial number, location, and date of installation. Since any properly installed system should last much longer than four years, keeping those records for at least four years makes perfect sense. Furnaces are not covered by this ruling. However, as long as you are keeping detailed information on the coil sitting on top of the furnace, why not go ahead and record the furnace information as well?

It is interesting to note that the condensing unit and coil are being listed separately. It is really not correct to say a condensing unit is 14 SEER, because it needs a matching coil. Since different matches yield different results, a single condensing unit can produce a range of efficiencies. To address this issue, the lowest rating point using the condensing unit manufacturer’s own indoor coil is what determines where a split system condensing unit may be used. So if a condensing unit has a rating of 13 SEER with one coil and 14 SEER with another coil, it will be considered 13 SEER unit. When using a third party indoor coil, the coil must be matched to the condenser. However, a third party coil may not be used to increase a condenser’s rating point above the manufacturer rating. For the purposes of meeting the minimum efficiency for your area, you may not use one manufacturer’s coil matched to another manufacturer’s condenser to obtain a rating higher than the condenser manufacturer lists. Obviously, this CAN be done, but it won’t qualify the unit as a 14 SEER unit if the condenser manufacturer lists a 13 SEER coil match for that unit.

Records must be kept for all cased coils. Records on uncased coils may or may not be required depending upon their use. If an uncased coil is a replacement part, you do not have to keep records on it.  An example would be replacing a leaky indoor coil on an existing system. However, if an uncased coil is used as part of a complete install, then you do have to keep records on that coil. You are not required to keep serial numbers on indoor coils. Many indoor coils do not have a serial number.

If you are looking for an easy way to keep this data, I suggest an Excel spreadsheet. Excel is a commonly used program and many of you may already have it. A spreadsheet does not take up lot of space and you can keep data on several systems on a single spreadsheet. Depending upon the number of systems you install in a month, you could have a spreadsheet for each month, or even one for the entire year.

I have put together a very simple Excel spreadsheet which you might like to use. The data handling functions of Excel allow you to sort and search data by different categories.  For example, a search of listings by model number or by address. Here is the link to download the file.

I encourage you to read it for yourself – as government regulations go it is pretty short. Here is a link to the ruling.

You might also like to read an excellent article by Jen Anesi in "The Air Conditioning, Heating, and Refrigeration News.”