Among the more frustrating and stressful challenges facing HVAC service providers is meeting customer demands for rapid diagnosis and repair of their systems. The stress problem occurs when customers want this done on the spot, which puts great pressure on the service technician.
The frustration comes when the problem is difficult to troubleshoot and diagnose with conventional methods. This is because, in many instances, HVAC problems are intertwined with several system components and frequently involve the power company’s connections. And things always get more complicated when problems only appear intermittently, which all but assures several trips to the site will be necessary. That’s when the situation also becomes more costly and inefficient.
For many HVAC contractors the solution to these types of dilemmas can be found in a compact electronic measurement system that can monitor and log the status of all HVAC functions, then provide a report that will enable technicians to accurately and efficiently provide the necessary repairs.
Taking a System Approach
While there are many measurement devices available to HVAC service technicians, they do not provide the power and flexibility of a fully-integrated electronic monitoring system constructed with modular components. Such an instrument can properly be called a “system” when it can provide several measurements of different types related to HVAC.
For example, a system is required to simultaneously monitor a three-phase power source while it is also monitoring several pressure transducers. On the other hand, if just a single measurement type needed, e.g., high voltage power, then it would be necessary to use just one of the system components.
Also, it would be highly useful to provide a means of collecting data over a period of time for the purposes of evaluating or optimizing HVAC performance, and also store that data for future reference.
Perhaps the most convenient system capability would be a communications component that would enable HVAC technicians or managers to monitor systems remotely. This would eliminate the need for a technician to stand by while measurements are being made and also eliminate the need for repeated visits to the site when intermittent problems such as irregular power supply may be impairing HVAC performance.
An Affordable, Efficient Solution
|The Validatar is a compact electronic device containing a configurable set of modules that measure, monitor, and record HVAC system performance as well as related equipment. Virtually any kind of transducer can be connected to this compact measurement system to provide data from ancillary systems such as heat-exchange units, pumps, blowers, and air handlers.|
An example of such a comprehensive and versatile system is the Validatar system from Span Inc., Indianapolis. It is a compact electronic device containing a configurable set of modules that measure, monitor, and record HVAC system performance as well as related equipment.
“This device will accept transducers of almost any sort and it allows us to make measurements of any sort, even gas densities, sulfur oxide, nitrous oxide, and so forth,” explained William Baker, Span president. “Virtually any kind of transducer can be connected to this compact measurement system to provide data from ancillary systems such as heat-exchange units, pumps, blowers, and air handlers.”
One module of this system, the low voltage monitor, accepts signals from 0-5 volt, 4-20 ma thermistors, RTDs, and switch position sensors via internal, electrically isolated circuits. As many as 10 signals can be measured and stored at once.
The Validatar system addresses high voltage issues with a separate monitor that measures 500-volt three-phase and single-phase power signals together with the currents for each phase. It computes everything: peak, minimum, and average volts and currents for each phase, KVA, power factor, actual power, KWH and also reports phase imbalance events for both voltage and current.
Improved Technician Efficiency
There are several common HVAC troubleshooting and repair issues that are eliminated by this system. Since performing on-the-spot troubleshooting can lead to an inaccurate diagnosis due to intermittent performance problems, the integrated Validatar contains a digital recording device that logs system performance data for up to 30 days. The results are stored both on removable memory as well as being cued up ready for sending to a master Modbus component.
HVAC system performance can be measured and logged hands-free anywhere from a few hours up to a month. Once the service technician is satisfied that the necessary monitoring interval has been achieved, performance data is then offloaded from removable memory via either thumb drive, memory stick, or Modbus.
Using an optional communications module with the tech’s computer attached, HVAC performance data can be monitored either via LAN or a through a WiFi network.
Captured data may then be viewed using any PC spreadsheet program, such as Excel, for accurate HVAC system performance diagnosis.
This is an important differentiator between a one-time single-shot test of HVAC performance and the use of an electronic device that monitors and records performance data over a period of time. The readings taken from sensor inputs are converted into real engineering units (degrees, psig, etc.) and time stamped according to settings provided by the service technician (e.g., four samples per minute).
“One of the major benefits of the system is that data recorded is organized in a manner that makes HVAC troubleshooting and repair relatively simple for the service technician,” Baker said.
Easy to Install and Use
Baker continued, “Designers made every effort to make the system, its components, its data format, its installation, and operation easy enough for even nontechnical people to install and operate successfully. Module enclosures may be attached either magnetically or permanently in the HVAC test environment. Little more than just listing the modules and their addresses in an Excel spreadsheet is required to set the system up. Single module operation is as simple as connecting the sense points and transferring data via the thumb drive to the user’s computer.
“Permanent installation of a troubleshooting system like the Validatar offers preventative maintenance. Besides providing a warning (in data form) before a system breakdown, comparing performance of critical components over time could foretell imminent failure. For example, a motor that normally consumes 2,000 watts suddenly is shown to be using 2,500 watts. This condition signals a need to check out multiple performance factors, making repairs faster, cheaper, and more efficient.
“That makes it a very affordable way to protect a customer’s HVAC investment” Baker noted. “And it also provides service techs with remote monitoring capabilities from the comfort of their offices.”
For more information, visit www.spaninc.com.
Publication date: 5/5/2014