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.

Sunday, June 26, 2016

What Quality is Your Parachute

Imagine that you are about to embark on a skydiving adventure. When choosing your parachute, where are you going to look? Are you going to be shopping at “Surplus Universe”, online from “DIY Parachutes”, or looking for a deal on Craig’s list? Not me! I want to choose my parachute at a place where everyone there has actually used a parachute and knows how they work. The reason is obvious: my life depends on that choice.

What about a NASCAR race? Would you want the cheapest car available? Probably not, because you could not compete with the folks driving real professional grade cars. No matter how good your driving skills are, you won’t even qualify if you are driving a Yugo.

You should take the same attitude when choosing your tools for any trade, especially HVACR. For a trades person, your tools are your lifeline. Poor tools limit your ability to work and can be dangerous. For example, when using a volt meter, your hands are holding the leads through which the electricity is flowing. The only thing keeping you from being shocked is the insulation quality of the leads. You do not want to be using a meter that has not been tested by an independent agency for safety. For HVACR work, the meter should have a safety category rating of at least III  and that rating should be verified by an independent agency. Further, a meter designed expressly for HVAC will offer features not found on the bargain meter, such as capacitance or microamp testing. The “Yugo” meter won’t allow you to check the flame rod circuit, hampering your ability to do your job.

Yes, the professional grade HVACR specific meter will cost more – but your life depends upon the quality of that meter. I prefer to purchase tools from wholesalers that specialize in HVACR because the people there know more about the products that they sell. Many of the employees at an AC Wholesaler have actually used those tools. AC Wholesalers also tend to carry better quality products than the discount stores. Further, HVACR wholesalers generally don’t stock anything that is dangerous to use. If you want people to take you seriously, don’t show up with a bunch of tools from “Surplus Universe.”

Thursday, June 16, 2016

Fathers Day 2016

I traditionally do a father’s day posting to my blog. This is the first father’s day since dad passed away on December 21, 2015 - one day past his 62nd wedding anniversary. He would have been 90 in January. Up until the last month or so, he got up every morning and made bacon and eggs. We used to grocery shopping together. At first he pushed the grocery buggy around, using it like a walker. Then as he got weaker he started using the motorized scooters. The last time we went shopping, I was not sure he could maneuver the scooter, so I pushed him in his wheel chair. It did not take long for me to realize my oversight – there was no place to put groceries! He could look at all the groceries, but we had no place to put them. I circled back and got a buggy. Now I was pushing dad with one hand and pulling the buggy with the other. However, I was not doing a particularly good job – which dad noticed. He offered to push the buggy. I reluctantly agreed to let him try. So I pushed his wheel chair and he leaned forward a bit and pushed the buggy. We must have been a sight! As funny as it must have looked, dad had helped solve the problem. You see, he was all about solving problems. Looking back, I realize what a blessing those outings to the grocery store were. If you pay attention, you can find meaning in the most mundane parts of life. I really miss those trips to the grocery store.

Lynn Stanfield's 89th Birthday January 30, 2015
Richard, Dad, Sally, Carter (me)

Tuesday, May 31, 2016

EPA Warns of Flammable Replacement Refrigerants

As the summer cooling season gets under way it is a good time to reiterate that flammable refrigerants should NOT be used as replacement for R-22 in existing systems. Some people are putting in R-290, which is simply propane.  A few have tried charging their systems with fuel grade propane. Not only is this dangerous, but fuel grade propane has lots of water contaminants and will screw up your systems, that is if it does not blow up. Yes, it is true that the EPA approved flammable refrigerants for a few very specific uses in systems with a very limited charge. However, these are NEW SYSTEMS ONLY! These systems are designed from the outset to handle a flammable refrigerant.

Your R-22 air conditioner of heat pump has many spark creating controls, such as relays and contactors. A leaky system recharged with a flammable refrigerant could have all the components for an explosion: fuel, oxygen, and an ignition source. The EPA has started fining companies for selling non-approved, propane based R-22 replacement refrigerants. Most have “22a” in their name. Unfortunately, there are still plenty of places to buy this stuff over the internet. A few other names include “Frosty Cool” and Eco-Freeze”. You should be wary of anyone that sells refrigerant directly to consumers over the internet.

I don’t believe regular HVACR wholesalers will have any of this stuff, and major refrigerant companies such as Honeywell, DuPont, or Arkema are not selling it either. They do each offer their own R-22 replacement solutions, none of which are flammable. Some legal replacement solutions have very small percentages of hydrocarbon components to improve oil return. Their hydrocarbon components are in such small quantities that they generally pose no threat of flammability. So what is the best thing to put in an R-22 system? R-22. Read more about the EPA actions and warnings here.

Wednesday, May 25, 2016

Daikin VRV Pro Tour

VRVProTour_Banner_Contractors.small

I took part in the Daikin VRV Pro Tour in Houston this past week. This was the first VRV Pro tour aimed specifically for HVAC Educators. The idea is pretty straight forward. There are way too few techs who understand variable refrigerant flow systems, and Daikin is trying to recruit some help from those of us whose job is teaching HVAC. The tour included a mix of class time and tours of the Daikin facilities in Houston. Daikin is making a very large investment in manufacturing and training facilities here in the US. They are serious about expanding the VRV/VRF footprint in the US. 

What is VRV/VRF? VRV stands for Variable Refrigerant Volume – and is a Daikin trademark name. VRF is variable refrigerant flow – the same idea without the trademark. The idea is to modulate refrigerant flow based on system load, and to achieve system zoning using refrigerant instead of air. Instead of ducting air throughout a building, you are piping refrigerant throughout the building. Indoor units are placed in the zones they are conditioning. Refrigerant is sent to the indoor units based on the needs of that unit. So in effect, you are zoning using refrigerant instead of air or water. 

The compressors are controlled by inverter drives, the metering devices are electronically controlled expansion valves, and the controls are communicating digital controls. Now imagine how difficult it is to find people who are properly trained to work on these, and you understand Daikin's quandary. They HAVE to ramp up their educational effort if they are to have any hope of expanding their market here. 

So did I enjoy the tour? Absolutely!
Should you go if you have an opportunity? Absolutely!
Did a two day class and tour teach me all I need to know to install and service VRV systems? Well...

If you want to learn more about Daikin products, go to daikincity.com and click on "Library" in the middle towards the bottom. That takes you to a page that allows you to download installation and application manuals for all their products.