Today, most HVAC equipment is still being serviced and adjusted with traditional analog or manual test equipment. Field service technicians are still using, among other instruments, manifold gauges, mechanical pressure meters, slack tube or inclined manometers, wet chemical CO2 testers, and slide rule efficiency calculators.

Although this equipment has served the industry well over the years, the need for faster, more accurate, and real-time analysis has become more than evident. Today’s smart test instruments are going digital.

“Many service technicians are reluctant to use digital instruments; there is a certain comfort in using what we are used to, what we were trained on, and, in some cases, we figure if we don’t know, we cannot be held responsible,” said Bill Spohn, product manager, HVAC, Testo Inc.

“Nothing could be further from the truth. If you do not conduct a test, it does not absolve you from liability. Information is power whether it is used for you or against you.”

With digital equipment, many errors with the measurement process are reduced or eliminated. Analog measurement errors can be the result of interpolation errors, calibration errors, poor repeatability of the measurement, and, most importantly, not having a procedure in place to consistently repeat the measurement process.

“Tuning a system should happen in real time, not after the fact with a very highly ‘averaged’ sample,” said Spohn.

“For example, in combustion testing, each squeeze of a wet kit bulb represents a different snapshot of the flue gas. A traditional test blends all those snapshots together into one fuzzy, time-averaged reading.”

Today, testing is not an option, but a necessity on every appliance that a technician might service.

In the end, digital instruments are faster, more accurate, more reliable, and have a higher repeatability than most analog tools. Digital instruments stay in calibration longer, allowing trending and more complex functions.

“Digital instruments allow data to be recorded and reported without human error, and provide reliable and accurate results for you and your customers,” said Spohn.

“Data can be recorded much faster, including seamless calculations in less time than any technician could ever do.”

In addition, this data can be recorded, whether or not the technician is present, using features like an online mode found in more advanced analyzers. In most cases, the data is an uneditable record, “so what you see was what was measured at the jobsite,” said Spohn.

“This is crucial in areas of the country that use VSPs (verification service providers) for third-party proof that work was done correctly in state energy and utility rebates and programs,” he said.

“Permanent records allow the user to track system changes and determine if the system is operating within the design parameters, or if changes have taken place.”

Digital analyzers allow a technician to take real-time tests and give real-time results. Thanks to smart digital equipment, technicians can now spend more time working with reliable information rather than interpreting readings.

Publication date:04/23/2007