The term "value" has been cropping up in Kele ' literature for quite a while, in regard to the many ways in which we strive to deliver real customer service. Some are obvious, such as our standard same-day shipping and our helpful sales and support teams. Often though, our products provide value in ways that aren't always noticed.
Just last month, we asked a group of contractors, building owners, and mechanical engineers to name the three most desirable qualities of a control system sensor. In other words, we asked them to define "value" in their own terms. They unanimously agreed on the following simple requirements:
1) The sensor should work when installed; 2) The sensor should work perfectly; and, 3) The sensor should continue to work perfectly forever.
Is this specification too much to ask? Perhaps it is, but it defines an ideal against which we can measure real-world performance. (At least they didn't require that the product mount and wire itself). In light of this fantasy specification, let's look closely at some of the more valuable features of PreCon thermistor temperature sensors which are sometimes overlooked. We'll translate the ideal into the real world, and see how close they really are.
PreCon's tightly controlled manufacturing process, pre-aging, and 100 percent screening result in a reliability which creates value far beyond the stated (5-year) warranty. Unless you have followed the 20/20 Insights closely, you may not know that less than 2 in 10,000 PreCon thermistors are returned to us for replacement. It's fairly obvious what this means financially to an installer. Every sensor which works when it is installed and lasts through the contractor's warranty period allows manpower to be used profitably on other jobs. With PreCon's documented performance, warranty replacements are almost nonexistent. In general, a single warranty replacement can wipe out all the money saved by using a less expensive, less reliable sensor. No other manufacturer comes close to PreCon's out-of-the-box success rate!
From the end user's perspective, the warm fuzzy feeling of security is maintained when every zone in the building works from the beginning. Isn't he then more likely to give the installer some repeat business? You bet!
PreCon Sensors Work Optimally
There are no "perfect" sensors, but there is one that's better than all the rest. To demonstrate, let's look at what PreCon's guaranteed accuracy means in terms of overall performance. PreCon's proprietary encapsulation material provides better protection against moisture and stress, and better self-heat dissipation than any competitive thermistor sensor. Sophisticated compounding and pre-aging allow PreCon to guarantee the lowest drift rate in the industry. No other manufacturer guarantees a sensor's accuracy five years after installation.
Just how much closer to "perfect" is a PreCon sensor in a space temperature application? Disregarding drift, most thermistors of a similar type can claim the same ± 0.36°F basic accuracy at zero power. As mentioned above, however, PreCon's special encapsulation keeps the effect of heat generated by the applied monitoring voltage and the sensor's own resistance to a minimum. The graph below depicts these self-heating errors as a function of the monitoring system's applied DC voltage. In the chart, "Brand X" represents a typical glass-bead type thermistor (most of PreCon's competitors), and "Brand Y" represents a competitor advertising fast response time as a trade-off to heat dissipation.
The most common BAS input voltage range is 2 to 3 VDC. At the 2 volt level, the PreCon sensor is within 0.3°F of its zero-power point, while the competition is within 3/4 to 1 1/2 °F. Since power (heat) is proportional to the applied voltage squared, the error value grows rapidly as monitoring voltage increases. When this error is added to the basic accuracy of the thermistor, errors begin to accumulate and become unacceptably large. Large enough errors cause energy waste and significant comfort problems if not corrected. PreCon sensors take the risk out of temperature sensing systems by reducing the errors added by the BAS.
Nothing lasts forever, but a properly installed PreCon thermistor will outlast the system it's hooked up to. A customer recently requested data on the mean time between failures (MTBF) for the PreCon thermistor sensors, since he had to comply with an unusually detailed specification for the Federal government (who else?). The result of PreCon's MTBF study sheds light on an otherwise hidden value.
The preferred calculation method for MTBF requires data which documents actual failure rates of components under normal service conditions. Since PreCon thermistors are installed in a wide variety of HVAC applications (by an even wider variety of installers), it is very difficult to tell if abnormal conditions may have contributed to a reported failure. Therefore, to err on the conservative side, PreCon has chosen to rate its products in terms of mean time between perceived failures (MTBPF). This rating includes all product malfunctions regardless of cause, and includes data from the enormous installed base of PreCon sensors.
The actual "perceived" failure rate found in PreCon's study is 0.00097 per 1000 hours. Inverting this rate and factoring in the typical continuous-use rate of 8,760 hours per year, we find that the MTBPF for the PreCon thermistor is just over 117 years! While not quite "forever", that's a lifetime of trouble-free temperature sensing.
