Today’s refrigeration gauges offer a lot more information
than the refrigerant charge. Some new tools are capable of calculating
superheat and subcooling.
To say that the company relies on smart system diagnostics a little would be a severe under-estimation.
The leakage gorilla is fed by “undersized return and inadequate supply, and driven by lowball mentality,” said Chesney. The lowball attitude is partially fueled by the new housing industry. “We’ve done 500 inspections in the Dallas-Fort Worth area,” he said. If a contractor raises his bid to include system performance verification in a housing development, it could result in that contractor losing the entire job.
“Code doesn’t deal with performance,” he said. “The focus is not performance-based. They call it a performance test when they find out there’s a leak. Performance to me is measuring dry bulb, wet bulb, airflow, and all the measurements of what that system is doing. You can take your Btu and true watts and come up with instantaneous EER.”
INSTANTANEOUS EER?
“EER in a lab,” Chesney explained, “is measured in unrealistic conditions that you can’t get in a real setting. There is no ductwork, there is an 80°F ambient, and 80° outdoors. You take the Btu divided by power consumption in watts - that’s the EER.“For instantaneous EER, we take a snapshot at a certain exact temperature.” The company has invested in more sophisticated tools “to try to capture a moment in time. A system is always changing.
“We want to bring the unit up to where it’s performing at its optimum,” he said. “A system is a balanced, fluid thing. If your temperature is dropping, your ability to cool the room is changing. Your EER is going to be sliding as well, because your Btu and watts are changing.”
Detailed measurements include wet bulb, dry bulb, and airflow (cubic feet per minute [cfm]). “We get a snapshot of all those things, but with a disclaimer that the conditions are always changing.”
Tradewinds says its most important tool is “the trained,
certified technician. Our techs, who are certified in several disciplines, are
trained to spot troubles and to take careful records of how the system is
working.”
EVERYDAY SMART
HVAC contractors can take smart steps to enhance their customers’ HVAC system performance. Performance enhancement is worth the extra cost, Chesney said. “We like looking at an a/c system as a system,” he said. “It’s not just a box; the ducts and registers, and where they are placed, all have to be balanced. The home is a real, breathing system,” he continued. “It’s not just something you buy from Wal-Mart; it needs to be engineered.“A contractor really needs to charge what he’s worth. It’s hard to do that when you have people stealing work by undercutting.”
Chesney recommended that contractors invest in training and high-tech tools, and distinguish themselves so that the bottom feeder is no longer a competitor. Then find customers who are willing to pay what you are worth. “There are people who will go with someone if they’re $50 cheaper. Let ’em go.
“Shoot for knowing what you need to do, and give the people a system,” he continued. “A condenser and an evaporator don’t make a system. Placement and matching have a huge effect” - on comfort and with an added benefit, energy efficiency.
A Tradewinds employee measures airflow at each register to
determine the cfm delivered by the supply, as well as the return cfm that is
feeding the system.
APPLIED SMARTNESS
Tradewinds Technologies has been involved with forming the curriculum and training of HVAC contractors in Texas through the Air Conditioning Contractors of America (ACCA). The company is an onsite verifier for the ACCA-Texas Utility’s Electric Delivery Installers Program, whose goal is to reduce the increase of electrical consumption in the state by verifying proper duct and high-SEER equipment installations.The company also is a certified carbon monoxide and combustion analyst through the National Comfort Institute, and a certified air balancing and diagnostic technician through the National Balancing Institute.
“Our sister company is an HVAC company,” Chesney said. “I go out and judge their installations. Our guys score 95-98 percent accuracy. We’re a very tight group; the camaraderie is good. Occasionally I’ll go back to my boss and say that we are weak in a certain area and we’ll do some in-house training.”
Tradewinds looks at detailed cooling capacities and charts what it is the unit should be doing at the measured operational conditions. A multitude of problems can be detected: restricted airflow, for example, or an inaccurate refrigerant charge. The data can point to a restriction in the coils, or poor return air. “We can tell all that once those numbers are in there.”
Software compiles the raw data and spits out information that a trained person can look at and determine, for instance, that warm air is bypassing the coil, or airflow is restricted, Chesney said.
“We give it back to the contractor, or we say, ‘Here’s what you need to fix.’ We don’t come in and try to sell ourselves. We work with the contractor.
“Sometimes the contractor and the homeowner can be on the point of litigation, and we can come in as a third-party helper, not as an adversary.
“Often we will take contractors out on our inspections and show them what we do,” he said. “We can shepherd them through to a whole new knowledge set.”
NEW TOOLS
This company’s tools fall into the category of “big-boy toys,” Chesney said. “There’s the Testo pistol-type 435 meter; it has a radio probe that can take measurements in four places at one time. We’ve been striving for accuracy and we can get eight measurements in the matter of a minute. It’s an instantaneous snapshot.” The company also uses the Fluke 438 power-quality analyzer.In spring and fall, he said, when the heat load is not so great, “temperatures can change drastically in a minute or two. I put a probe in one place - I call it the anchor point - then I calibrate the probes together and the software automatically brings it up to that correction.
“We can actually take that one tool up into an attic. If we need to take a duct traverse, we can do that,” as well as getting wet bulb and dry bulb temperature, static pressures, and using a pipe clamp to take line set temperatures. The tool stores the measurement data for downloading and analysis. The company also uses the TSI Accubalance airflow hood for measuring flow out of the grilles and for airflow balancing.
Smart contractors need to use the training and instruments available to differentiate themselves from their competition, he said. “There really isn’t anything like knowing that you can guarantee what you are giving to your clients.”
Publication date:08/27/2007
