As competition increases and customer expectations rise, it is ever more important for home comfort companies to install and service equipment effectively and minimize mistakes and callbacks.
To set up equipment properly and optimize its performance, technicians use testing tools and analyzers to evaluate system performance and guide them in making the proper repairs and adjustments. Oil & Energy recently caught up with two of the industry’s leading experts on testing tools, Bill Spohn of TruTech Tools and Peter Cullen or Wohler USA, to discuss essential tools for heating and cooling technicians.
Bill Spohn, CEO, TruTech Tools
One measurement that is essential when working on all warm air and air conditioning systems is airflow, according to Spohn. Air is the heat transfer medium for those systems, and it needs to flow over the heat exchanger or evaporator in the correct volume at the correct rate.
“You need to know what the airflow is in heating and cooling,” he explained. “You’re trying to change the state of the air: to heat it, cool it or dehumidify it. If the heat exchanger or coil is not receiving enough air, it could cause poor performance or equipment malfunction. The heat exchanger or evaporator coil is designed to radiate or absorb a certain number of BTUs per hour, and if the airflow is not picking it up or taking that away, it could cause the system to go over limit or stress the components.”
Airflow is the most critical measurement in air-based systems, according to Spohn. “It is the first thing you check. Before you start making ‘expensive air’ by adding energy, you have to make sure the flow rate is correct.”
“There are a dozen different ways to make measurements of airflow movement,” Spohn said. The most common method is to perform an external static pressure test and infer the airflow rate. A hot-wired anemometer is effective for measuring in-duct airflow but is difficult to use on supplies or returns. A direct measurement of supplies and returns is possible using a rotating vane anemometer, which measures the airflow directly and does not require any correction for air density.
The correct airflow rate varies by system and load, so technicians need to understand what their targets are to compare their measurements. With that information in hand, they can set the airflow properly, which should be a prerequisite to adjusting the heating or cooling systems.
The static pressure method is the most commonly used way to determine system airflow. However, this method relies on the manufacturer’s system characterization, which relates static pressures to airflow rates. This characterization is like a system’s fingerprints, says Spohn: unique and not transferrable to other equipment. That is, an airflow reading via static pressure test on one system does not yield the same airflow on a different system, even at the same static pressure.
Technicians can infer accurate airflow rates with sound methodology and accurate system information, or they can use more expensive tools. A direct measurement tool like a TEC TrueFlow Air Handler Flow Meter or TSI Low Flow Balometer (or capture hood) reads airflow directly and accurately, but at a system price of about $1,600, they are more expensive than other tools for the job, Spohn said. “Testing does get easier and more accurate as you spend more money,” he added.
Incorrect airflow is a leading cause of air conditioning malfunctions. Another common problem is incorrect refrigerant charge, which techs can measure using a gauge set and temperature probes
It is important for technicians to sequence their measurements correctly, according to Spohn. “You need to know what your target values are before you begin to measure. A lot of technicians immediately attach their gauges connected by lengths of hose,” he said. “You can affect the system unnecessarily by hooking up the gauges first.” For example, when refrigerant enters the hoses and is removed from the system upon disconnection, the system’s charge and hence its performance characteristics could be changed.
For hydronic systems, technicans also need to measure pressure drops in order to ensure that a system is functioning properly. A hydronic manometer enables them to measure pressures and determine flow rates in order to balance the system properly.
Spohn noted that many technicians continue to use analog tools such as wet kits for testing combustion, but digital tools can offer important advantages. “Wet kits are still good, but you can get so much farther for less money with some digital tools,” he said. “On the combustion side, digital analyzers are now available for $550, and a wet kit is almost $700 in some cases.”
Wet kits also have limitations. “They take what I call a slow, blurry snapshot of one moment in time,” Spohn added. “A digital analyzer stays attached and is constantly analyzing, providing a richness of information over time as you make adjustments.” Analog equipment generally requires more maintenance, and there
can be a lot of steps involved simply to facilitate an accurate measurement. “You get a better information stream from the digital,” he added.
Technicians who share Spohn’s desire for accurate measurements might want to add a NOx filter to their combustion analyzer, if it does not already have one. The filter makes measurements more accurate by eliminating the possibility that the analyzer will mistake NOx for carbon monoxide (CO) and provide false high CO readings.
Knowing how to take accurate measurements is vital for the company’s success, according to Spohn. “If you make a wrong conclusion, you either waste the company’s time and money or the customer’s time and money. And you have to worry about the boss. If you keep screwing up in their field, you’re going to have to worry about the impact on your job.”
He recommends that techs always “test in and test out,” meaning that they take measurements at the beginning and end of a troubleshooting visit or tune-up so that they have data readings that reflect the adjustments they have made.
Adding printers to testing tools provides several benefits: The company has written records regarding the service call, and they can share those with the customer, which reflects well on their professionalism, Spohn said.
Peter Cullen, CEO, Wohler USA
One of today’s hot button issues is carbon monoxide poisoning, and home comfort companies can help customers and themselves by routinely testing ambient air for carbon monoxide and reporting the results, according to Cullen. “If you see something wrong, make sure you let the customer know,” he advised. Carbon monoxide is a safety threat to both the customer and the company’s technician,
so it makes sense to test for it routinely.
He also recommends that companies find new uses for the tools they are carrying. For example, a vacuum that is used to clean out boilers and furnaces might also be useful for cleaning out dryer ducts to prevent fires, and the company is performing a new service for the customer.
Cullen also recommends that technicians who carry multi-function analyzers familiarize themselves with all the functions so they are not overlooking important functionality that can help them on the job.
Testing tools can also help with customer relations, because many customers are curious about system performance and they appreciate the specific information that a well-equipped technician can provide. “Customers are paying more attention than they have in the past,” he said. “It’s a very informed customer base. We are seeing a lot more traffic on the Internet from people looking up specific boilers and furnaces.”
He recommends that technicians test systems before and after servicing and share the data, so that customers feel assured about the company’s competence and expertise. “They want you to test, not guess,” Cullen said. “You can’t charge for professional guesswork.”