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.”

Monday, July 18, 2016

Pull a Deep Vacuum Twice as Fast

How much would you pay for a vacuum pump that could evacuate a system in half the time of your current one? Think of how much time it would save you! The good news is you can probably cut your evacuation time in half just by changing your vacuum setup.  If you are like most techs, you are using ¼” hoses and your standard manifold while pulling through Schrader valves. And that is exactly the problem. The Schrader valves, gauge passages and small hoses all add up to a big restriction. No matter how wonderful your pump is you can’t pull a vacuum quickly through that setup. So the answer is not to get a new vacuum pump, it is to connect it with less restriction.

This will involve some financial investment in better equipment, but it will cost less than a new vacuum pump and yield far more results. First, I would purchase two core removal tools. They cost about $50 each. Removing the Schrader core while you evacuate the system is the single most important step in reducing the restriction and reducing the time it takes to evacuate a system. This $100 investment should cut your time in half, even if you don’t change anything else.

The next recommendation is to get a short ½” hose to connect to the ½” port on your vacuum pump. Appion makes a 6” hose with a ½” connection on one end and a 3/8” connection on the other. If you are using four port gauges with a 3/8” vacuum port, this short hose will connect right to it.  This costs around $35. So for $135 you can easily cut your vacuum time in half if you are already using four-port gauges with a 3/8” vacuum port.

You don’t have a 3/8” vacuum port on your gauges? If you are using valve core tools you don’t really need gauges to pull a vacuum. The valves in the core tools allow you to blank off after the vacuum is pulled and connect your charging hoses and refrigerant. With that in mind, put a 3/8” tee on the short hose which is connected to the vacuum pump. Finally, connect two hoses from the tee to the core tools. Appion makes ½” hoses with a 3/8” connection on one end and a ¼” connection on the other which will allow you to do this. These are about $75 each. Since you are using valve core tools, you can connect your vacuum gauge to the side port of one of the core tools.

A couple of final notes. Change the oil in your vacuum pump! Vacuum pump oil gets dirty every time it is used, and dirty oil reduces the vacuum pump’s ability to pull a good vacuum. Not to mention letting running the vacuum pump with dirty oil can shorten its life and you WILL need a new vacuum pump.  You should always start out with fresh oil every time you use your vacuum pump. For large jobs, or particularly dirty systems you may need to change the oil more than once. And of course, use a vacuum gauge. Without a vacuum gauge you don’t really know when you have a good vacuum. You can get a micro BlueVac vacuum gauge for around $100.

Thursday, July 7, 2016

Refrigerant Cylinder Color

“Hey, grab that Wedge Wood Blue cylinder and let’s go charge this unit. No, that’s the Royal Blue one. There it is, right next to the Medium Blue cylinder. No, that is the Sky Blue cylinder. Gosh, don’t you know your refrigerant colors?”

Back in the good ole days, we just had a few colors to keep up with. Most of us just had to recognize the difference between green, white, and purple.  Now there are so many different shades that not even an interior decorator can keep up with them.

AHRI Guidline N is where the industry normally lists the colors of the different refrigerant cylinders. The latest version lists 46 different colors – the big box of crayons. That is why you should always read the cylinder label, not just go on the color. Guideline N describes four classes of refrigerants and they allow the same color to be used in different refrigerant classes. So it is possible that Sky Blue cylinder could have either R-134a or R-13. The only way you know is to read the label.
PMS 413

In the future you will have an even better reason to read the label – all refrigerant cylinders will be the same color. The 2016 edition of Guideline N specifies that all Refrigerant containers should be painted light green gray (RAL 7044 corresponding with PMS 413) starting in 2020. This is spelled out in section 4.8.
PMS 185

One critical color to recognize is red – PMS 185. Cylinders containing flammable refrigerant should have a red band on the shoulder or top of the container. This is specified in section 4.7. Not only should you read the cylinder label, you should be familiar with the properties of any refrigerant you handle. If you start working with a new refrigerant, you should read the safety data sheet. Most refrigerant manufacturers also have refrigerant properties and handling instructions online. You can download and read the details of Guideline N for yourself  HERE

Monday, July 4, 2016

Keep the Fireworks Out of the Fusebox

Fuses are one of the simpler devices that we work with, yet techs do not really know some important fuse specifications. What you don’t know could hurt you if you use the wrong type of fuse as a replacement. Fuses have five important ratings: voltage, amps, interrupting, one-time or time delay, and finally whether or not it is current limiting.  Most techs are familiar with the volt rating and the amp rating, but a lot are unfamiliar with the interrupting rating.

Although all fuses are designed to open when the current exceeds their amp rating, this does not happen instantly. In the case of a dead short, the fuse will be subjected to a much higher level of current for a fraction of a second. For a fraction of a second, the fuse can be exposed to 100,000 amps, causing it to explode like a bomb! The amount of current the fuse can withstand and not explode like a bomb is called the interrupting rating, listed as IR on the fuse body. Inexpensive fuses have an interrupting rating of 10,000 amps – which is comparable to most breakers. Better quality fuses have much higher interrupting ratings – such as 200,000 amps.

Two fuses can have the same volt and amp rating but have vastly different interrupting ratings. If you replace a fuse which has a 200,000 amp interrupting rating with one which has only a 10,000 amp interrupting rating, you are creating a bomb. If you take look at the two fuses pictured here, you can see that they are both 600 volt, 30 amp fuses and are physically interchangeable. However, the one on the top has a 200,000 interrupting rating but the interrupting rating of the fuse on the bottom is only 50,000. They are not functionally interchangeable.

Further, the fuse on the top is designed to be a current limiting fuse. This means that it limits the amount of current that can pass downstream of the fuse. I can hear you saying “all fuses are current limiting.” Not really. During that fraction of a second after a direct short, thousands of amps pass downstream through the fuse. A current limiting fuse limits this spike. Typically, the spike is limited to 10,000 amps. The importance of this is that it can reduce or even prevent an arc flash from happening in the equipment down-stream of the fuse. This is why industrial and commercial services usually protect their service panels with current limiting fuses which have a high interrupting rating. Keep the fireworks out of the fusebox. Always replace fuses with ones that meet ALL the fuse specifications, not just the volt and amp ratings.