An affordable system automates the mechanical troubleshooting of HVAC (Heating, Ventilation, Air Conditioning) systems without the need for cumbersome tools or meters, speeding up diagnosis and repairs.
by Span, Inc.*
One of the most frustrating and stressful challenges faced by HVAC system providers is meeting their customers' demands on a quick diagnosis and repair of their systems. Stress comes when customers want such tasks to be performed where the equipment is installed, placing enormous pressure on the resources of service technicians.
Frustration originates when the problem is difficult to solve and diagnose with conventional tools and equipment. This is because in many cases HVAC equipment problems are interrelated with various system components and very often have to do with the power company's connections. And things get more complicated when problems only appear intermittently, which ensures that several trips to the site will be necessary. It is at that time that the situation also becomes more expensive and inefficient.
For many HVAC contractors and service organizations, the solution to these types of dilemmas lies in a compact electronic measurement system that can monitor and record the status of all HVAC functions and then generate a report that will allow technicians or engineers to accurately and efficiently provide the necessary repairs and spare parts.
An approach as a system
Although there are many measuring devices that can be used by HVAC technicians, most of these devices do not offer the power and flexibility of a fully integrated electronic monitoring system, built with modular components. Such an instrument can be accurately referred to as a "system" when it can perform several measurements of different kinds related to HVAC systems.
For example, a system is needed to simultaneously monitor a three-phase power source, and at the same time monitor several pressure transducers. On the other hand, if only one type of measurement is needed, for example, high-voltage energy, then it would be necessary to employ one of the components of the system.
It would also be very useful if the system had a way to collect data in an appropriate period of time to evaluate or optimize the performance of HVAC equipment. The system should also be able to store the data for future reference.
Perhaps the most useful function of the system would be a communications component that would allow HVAC technicians or managers to remotely monitor systems. This would eliminate the need to have a technician present while measurements are being made and it would also not be necessary to make repeated site visits when intermittent problems, such as an irregular power supply, may be affecting the performance of HVAC equipment.
An affordable and efficient solution
An example of such a comprehensive and versatile system is Validatar by Span, Inc. (Indianapolis, IN), a compact electronic device that contains a configurable set of modules that measure, monitor and record the performance of the HVAC system, as well as the equipment associated with it.
"This device accepts transducers of almost any type and allows us to make measurements of any kind, including gas density, sulfur oxide, among others," explains William Baker, president of Span. "Virtually any type of transducer can be connected to this measurement system to supply data from complementary systems such as boilers, heat exchangers, pumps, blowers and air conditioning units."
One of the modules of this technology, the low-voltage monitor, accepts signals from 0-5 volts, 4-20 ma, thermistors, thermo resistors and switch position sensors using isolated internal electrical circuits. Up to 10 signals can be measured and stored simultaneously.
The Validatar system processes the high voltage with a separate monitor that measures 500-volt three-phase power signals and single-phase signals, along with the currents of each phase. It records everything: peaks, minimum and maximum volts and average volts and currents of each phase, KVA, power factor, actual power, KWH and also reports events of imbalance between phases of both voltage and current.
Improves the efficiency of technicians
The technology eliminates several of the common difficulties associated with troubleshooting and repairing HVAC systems. Because performing repairs at the system installation site, using conventional tools and indicators, can lead to inaccurate diagnostics, due to intermittent performance issues, the Validatar integrated system contains a digital device that records performance data for a period of up to 30 days. The results are stored in the removable memory and are encoded to be sent to the Modbus master component.
The performance of the HVAC system, over a period that can range from a few hours to a month, can be measured and recorded remotely. Once the service technician ensures that the necessary monitoring interval has been reached, the performance data is downloaded from the removable memory, either via the miniature storage unit, USB stick or Modbus.
By using an optional communications module with the technician's computer, HVAC performance data can be monitored over a LAN or WiFi network.
Then, the captured data can be visualized using any calculation program such as Excel, to make a diagnosis of the accurate performance of the HVAC equipment.
This is an important difference between a timely evaluation of HVAC system performance, using conventional meters, and the use of an electronic device that monitors and records performance data over a period of time. Readings taken from sensor inputs are converted into actual engineering units (grades, PSIG, %, etc.) and into timestamps adjusted to the settings provided by the service technician (e.g. four samples per minute).
"One of the main advantages of the system is that the recorded data is organized in a way that allows troubleshooting and repairing HVAC system problems to be relatively simple for service technicians," says Baker.
Improves technician efficiency
Baker goes on to argue that "the designers strove to make the system, its components, the format of its data, its facilities and operation easy to handle and install by people without much technical knowledge. Attachments to the module can be attached magnetically or permanently in the HVAC verification environment. To configure the system you only need to make a list of the modules and their addresses in an Excel spreadsheet. To operate a single module, it is only necessary to connect the sensor points and transfer data through the miniature storage unit to the user's computer.
The permanent installation of a troubleshooting system such as Validatar allows for essential preventive maintenance. In addition to generating an alarm signal (in the form of data) just before a system breakdown occurs, comparing the performance of essential components over a period of time can help predict impending failures. For example, a motor that normally consumes 2,000 watts is suddenly recorded using 2,500 watts. This condition signals the need to review various performance factors, which makes its repair faster, cheaper and more efficient.
"That makes this system a very affordable way to protect customer investment in HVAC systems," Baker says. "And it also provides service technicians with remote monitoring features, from the comfort of their offices."
* For more information, contact Span, Inc., 4404 Guion Road Indianapolis, IN 46254; Phone:(317) 347-2646, Collect Call: (800) 774-2410; Fax: (317) 347-2640; or visit the Span website: spaninc.com
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