Monthly Archives: January 2012

When a homeowner or business calls for a plumber, electrician, HVACR, or appliance technician, who is it that actually shows up at their door to provide the service they requested?

Often, a customer isn’t really certain what the answer to the above question is because they’re not completely familiar with the way the service business works. When they do some research and place the call, they may be requesting service from a local independent operator, or they may be calling an area office of a large chain. In either case, the person who shows up may be someone who is considered to be a journeyman in their craft, having been tested and licensed as an individual….or they may not be.

In some states, for example, a service organization can have only one person on staff who holds the required license, and as long as that person’s name appears on the invoice issued to the customer, any other person employed by the company can perform the service. That means that the person who shows up at the door to clean the drain, intall the new air-conditioning system, or repair the dishwasher may actually be the person who has been deemed qualified via whatever licensing process applies, or they may be an employee of the company who does not hold an individual license.

From the consumers perspective, all this means is that they should always remember to ask questions. Ask about how the licensing that a particular company advertises actually applies regarding the technician who is going to show up. And, be educated about the issue of “licensing” and “certification”, and ask questions about that process. Certifications can, in some cases be required, such as EPA certification for a refrigeration technician, or they may be granted via a trade association. Like I said….ask.

A technician who isn’t “licensed” by a state entity such as a registrar of contractors, may in fact be “certified” by a non-government entity. And, having been through a certification process, may be eminently qualified to do the work that needs to be accomplished. Then again, a technician who is “licensed” by a state entity may not, in fact, be as competent as necessary to effectively perform the work.

In some states, not only are service company owners licensed, but each technician requires a license to be allowed to work. And, they may be required to document that they have completed a given number of hours in continuing education every year in order to be allowed to renew that license. And, that’s all well and good….except for the fact that the continuing education process may be, well, pretty much a joke. If a technician is just showing up for an 8-hour class, having picked the simplest thing possible from an approved list, and if the main focus of the entity providing the “training” is revenue, then all that has occurred is that the technician has, as we say, filled-in-a-square, and winds up with a renewed license.

What’s a consumer to do? Ask. Ask for an explanation of how a technician becomes licensed or certified, and ask about the continuing education process that allows them to keep that license or certification. Perhaps your state doesn’t even have a technician licensing program, but the company you are calling has an effective in-house training program and has embraced an industry certification process. Or perhaps the person who actually shows up at the door isn’t licensed or certified at all, but has been “unofficially” trained and has been in the field for many years, knows the particular equipment that needs to be repaired or the situation that needs to be handled ‘upside down, inside out and backwards’, and can do what needs to be done in an efficient and professional manner.

How would you know? Ask.

Until next week….

Learn from yesterday….Live for today…..Look forward to tomorrow.

Jim

Troubleshooting. It’s what we do as an HVACR technician. And, when it comes to troubleshooting, there are some simple steps to understand about the process. Here’s one way to get to what we understand is the bottom line about our job…..figure out what’s wrong, fix it, and get paid.

First, what is the specific type of equipment?

Second, what is the customer’s description of the problem? (Don’t write this one off because the customer isn’t a technician. People are familiar with the sounds, feel, and performance of their HVACR system.)

Third, what kind of history is there regarding repairs on this equipment? Who has worked on it before? What did they do?

Fourth, what is the sequence of operation when this equipment is working properly?

Fifth, what are the symptoms you encounter when you evaluate the operation of the equipment?

Sixth, what specific troubleshooting information is available from the manfacturer regarding this particular piece of equipment?….fault codes?….wiring diagrams?….step by step diagnostic procedures….service bulletins?

And, while you consider the steps above, determine the correct answer to the following problem:

The equipment is a 240-volt, single-phase split system heat pump, and the customer’s complaint is that there is “no cooling.” They also tell the dispatcher that they had the same problem at the beginning of the cooling season last year, at which time a part was replaced and the unit operated OK until now. When you arrive, you find that while the indoor and outdoor fan motors are operating normally, the root of the problem is that the compressor is attempting to start, but kicks off on its overload. When you remove the access panel, you check the schematic, and note the wiring configuration for this compressor, shown below in Figure One.

Figure One

 

However, when you survey the equipment, expecting to find the two run capacitors (Ca and Cb) wired in parallel (meaning that their value would be added to provide the proper PSC circuit for the operation of the compressor while only the Ca capacitor would be used in the off cycle to provide a trickle circuit through the start winding), you discover that the wiring has been modified and the compressor circuit now only employs one run capacitor as shown below in Figure Two.

Figure Two

 

What is the specific cause of this compressor’s failure to start, and what do you need to do in order to get this unit operating again?

Until next week,

Learn from yesterday…..Live for today…..Look forward to tomorrow.

Jim

 

 

 

 

 

 

When taking a simple and direct approach to understanding the fundamentals of HVACR, a technician evaluating the operation of a comfort cooling system needs to understand the operation of the refrigeration and air flow systems in the equipment individually and collectively. They are considered as being in balance with one another, simply because it’s universally understood that a refrigeration system cannot accomplish heat transfer at optimum efficiency without the proper amount of air flow throughout the ductwork, and the air handling system cannot provide maximum comfort if the refrigeration system isn’t operating as designed.

In Figure One, the TXV, DX system shown is accomplishing the maximum level of heat transfer possible.

 

Figure One

 

Consider first that the metering device in this system is capable of delivering the proper volume of refrigerant to the evaporator coil due to the synchronicity of the three pressures in the valve (evaporator pressure, spring pressure and bulb pressure), and, second, because of the correct volume and velocity of air flow through the coil. Note that the saturation temperature of the refrigerant is 38-degrees, and that the temperature drop through the coil is 20-degrees. And, we can also see that the evaporator superheat in this system is 12-degrees when we consider the last point of liquid in the 38-degree coil, and the 50-degree temperature reading at a point on the suction line directly ahead of the TXV sensing bulb.

Figure Two shows an example of the air handling system that makes the temperatures above achievable.

 

Figure Two

 

The first factor we want to mention regarding this illustration is that the equipment capacity is 3 tons, due to the application of the fundamental rule that an efficient system will operate with an air flow of 400 CFM per ton. (The total air flow shown in the return ductwork and the supply plenum is 1200 CFM.)

Note also the reduction of the supply plenum after the first four supply registers of 100 CFM each are served; then again after the next set of registers, which involves three at 100 CFM each and the bathroom registers at 50 CFM each, and then the third reduction in plenum size at the final segment of the supply duct system. This design of the supply ductwork, along with the turning vanes, allows the air handling system to operate with minimum noise and the necessary velocity required for proper throw from the supply registers into each room in the building. And, it also ensures that the static pressure in the system will be correct.

The factors to consider here are the slightly negative -0.03 WC (Water-Column-Inch) pressure in the return system, which allows for the free flow of air through the return, and the fan static pressure of 0.4, which is achieved due to the -.02 pressure at the fan inlet and the 0.2 pressure at the fan outlet. The proper static pressure in this system is achieved through the application of a manufacturer’s table for airflow characteristics, such as the one shown in Figure Three.

 

Figure Three

 

This table shows that the indoor fan has a maximum capacity of 1360 CFM while operating against a 0.4 static pressure, which means that the blower will easily achieve the required 1200 CFM for our three-ton system.

With the duct system and blower allowing for the proper return and delivery of air throughout the building, the balance between it, and the refrigeration system, will be achieved, resulting in the proper operation of the equipment from a fundamental perspective.

Until next week…

Learn from yesterday…..Live for today…..Look forward to tomorrow

Jim

I’m a believer in the theory that change, no matter what it entails, makes people uncomfortable. And, it’s due to that discomfort that people are often stubborn about change, preferring that it didn’t happen…..even if they know it’s just the way things are sometimes (I’m no exception).

I was reminded of this in one of the simplest ways imagineable. I had to make a change in getting my copywork done.

For what seems like forever, I’ve patronized the OfficeMax near Irvington Road in Tucson (not too far from our office, so it’s convenient), and the main reason I kept going back there was the person who almost always took care of me when I went to that store for copywork. To give you a visual of her, she reminded me of the young woman who stars in the movie “The Girl With The Dragon Tattoo”, dark hair, petite, and a few tattoos (I don’t know if any of them were dragons, though).

From a customer service aspect, this lady had it figured out. Whenever I walked in, she knew that I had a master copy ready, and would often need 1,000 copies or so, which meant she could be in the middle of something else, recognize that she could just take a moment to clarify what I needed, and get it started, allowing the job to run while she was handling other tasks. The reason this is important is that, often, those other tasks were for customers who weren’t there on business, but instead getting some personal work done, like having photographs copied. And, the fact is, photocopying photos for somebody is a time-consuming process because the reason they’re getting the photos copied is that they want them re-sized. This takes time and trial and error to make sure the copy comes out the right size.

A while back, needing some copywork done (mailers for an upcoming training workshop), I went back to the above-mentioned OfficeMax, expecting to once again trust that “my” dragon tattoo lady would wrap the project up quickly and correctly so I could be on my way and get the mailing accomplished according to my desired timetable. But, alas, it wasn’t to be. She wasn’t there. Somebody else was, which, at first, didn’t really mean much. But, as I stood there while he struggled with a photograph copy task, I sensed that change was afoot, but I stubbornly waited, hoping he could perform up the standard I was used to there. He couldn’t.

After struggling with one photo, and, for the most part, avoiding looking in my direction, he reached for a second photograph and continued. It was at that point that I could see that he had a stack of photographs to get through, so I decided that I wouldn’t waste any more of my time there, picked up my master copies, and left. I had other errands to run in other areas of town, and wound up at an Office Depot, where I took the necessary time to explain what I needed, then paid for, and took my copies with me a short time later. I was back on schedule to get the mailing accomplished, even though I couldn’t get things done at my usual place.

And, though I know that should have been ‘it’ as far as the copywork situation, I was again stubborn a few days ago. As it turned out, I had another situation that required some copywork, and I once again made the trip to the OfficeMax. When I walked to the copy desk this time, not only was ‘she’ not there, nobody was. I waited. And, after waiting some more, I got the attention of one of the other store employees and inquired about somebody being at the copy desk. His response was that somebody would be there soon. I waited.

There were two other employees in the store, but neither of them headed for the copy desk. I waited.

After a time, the first person who told me somebody would be coming soon, got together with the other two, and they stood nearby, kind of not looking in my direction. I waited.

And, I’m sure that you’ve figured out by now that I decided not to wait anymore. And I realized that I shouldn’t have been so stubborn. I shouldn’t have made the second trip there. I should have just accepted the change, and realized that the change was going to happen, no matter how I would rather not have to deal with it.

The lesson…..things will change, even the seemingly most insignificant things, no matter how stubborn we are.

Until next week.

Learn from yesterday….Live for today….Look forward to tomorrow.

Jim

 

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