Digital combustion analyzers such as this new Testo model are designed to give contractors and technicians the ability to perform real-time tests, even on startup. Startup testing can ensure that the system is working at design conditions.
FLANDERS, N.J. - Proper combustion analysis can help many aspects of commercial-industrial heating system performance. Typical measurements are taken of oxygen (O2), temperature, and carbon monoxide (CO). From these three measurements a service tech or in-house service can diagnose excess air, carbon dioxide (CO2), and combustion efficiency (sometimes referred to as stack loss), said Bill Spohn, product manager HVAC with Testo Inc.

One of the older analysis technologies is the "wet kit," which provides average readings of these parameters. This manual combustion efficiency test equipment consists of a stack thermometer, draft gauge, wet chemical CO2 tester, slide rule, and smoke pump, Spohn explained.

Enter the latest analyzers - digital combustion analyzers. "They help us see the dynamics of an operating system," Spohn said, such as venting and draft conditions. Based on these live readings, "We can make adjustments and see changes."

Varied And Effective

The digital analyzer is to the wet kit what a video camera is to still photography, Spohn said. Common uses are for commercial-industrial heating systems that use light and heavy oil, natural gas, propane, wood, and more exotic fuels.

"One meter has settings for wood at varying degrees of dryness," which affects its rate of burn, Spohn said. Another measures composted organic material. It also is effective for pelletized fuels, he said, which are essentially compressed sawdust and are popular in Europe; their use may become more widespread in the United States.

The chief advantage of electronic combustion analyzers is their ability to capture and document real-time measurements, Spohn said. This allows a heating system to be tuned in real time, not after the fact with an averaged sample, he said.

"Each squeeze of the bulb represents a different snapshot of the flue gas. A traditional test blurs all those snapshots together into one reading." Electronic analyzers, on the other hand, give contractors and technicians the ability to perform real-time tests, even on startup.

With a portable printer, flue gas readings can be printed on the spot and attached to service records.

Pro And Cons

Older digital flue gas analyzers, Spohn said, did have some early reliability issues. Today's products, he said, are built to last and are available at "a fraction of their cost a decade ago."

Reliability is equally important to service contractors. "We have not had one device failure to date with any of the [newer Testo] equipment, utilizing only minor preventive maintenance," said Gary Sippin, vice president, Sippin Energy Products, Monroe, Conn. "In addition, the oxygen cells on our units have been in service nearly three years without replacement."

Other contractors are still comfortable with the results from their older manual combustion test kits. However, difficulty in following critical maintenance procedures associated with wet kits has often led to dubious results, pointed out Spohn. "We found that on a regular basis, most of the liquid CO2 analyzers were not maintained and filled properly with liquid," confirmed Sippin. "This would produce false readings."

In addition, "Because manual flue gas kits do not allow for real-time combustion analysis, technicians who are in a rush may not take the extra time to retune the burner properly if their readings aren't ideal," said Sippin.

Moreover, "Electronic flue gas analyzers have been the best training tool I have implemented in the last five years," said Charlie Bash, general manager of Johnson's Heating & Supplies, Norvelt, Pa. "A digital analyzer teaches a tech about what impact he is making as he changes a system adjustment or component."

With a digital analyzer, a technician can dial in a heating system, adjusting CO2, O2, CO, and stack temperature.

The Importance Of Startups

Using an electronic combustion analyzer, Spohn said, the commercial-industrial heating contractor could be sure that he or she has the setup correct for a new installation or seasonal startup. Contractors could also take precise baseline measurements for new clients.

"It would be important to test in and test out," to protect the contractor against unfair claims, Spohn said.

"In the last five years or so, things have really started to get off the ground" as far as new products and technologies go, as well as contractor acceptance of them, he said. "Many heating companies have made the decision to upgrade their field service staff to electronic digital flue gas analyzers."

Too often the industry assumes that the system is working at design conditions, he continued. Things can happen between the manufacturer's facility and the client's facility that can change the equipment's performance; parts can be damaged in transit, for example. Product misapplications can create performance errors. Taking startup measurements in real time helps the contractor put the system back on track.

"You cannot do a test at startup with a wet kit," said Sippin. "It is physically impossible to take the sample fast enough and do the slide rule calculation.

"I consider startup testing more important than steady-state testing when it comes to equipment reliability," he said. "Reliability relates directly to customer satisfaction in the form of reduced callbacks."

Important Parameters

With a digital analyzer, Spohn pointed out, "A technician can dial in a heating system, adjusting CO2, O2, CO, and stack temperature to achieve the desired settings. All competent oil burner technicians realize that visual flame analysis is not a valid way of tuning a burner, and, in fact, is nearly impossible on many positive-pressure systems."

Spohn said service technicians can use the electronic analyzer's CO feature to detect carbon monoxide in the vent or conditioned air. "We have drawn a reliable relationship between the presence of carbon monoxide and smoke" in oil heating systems, said Sippin. "Although this does not eliminate the need to use a smoke spot test, it does indicate whether smoke is being produced during the normal operation of the oil burner and provides a much more accurate analysis of smoke and particle emissions."

Customer perceptions are every bit as important as actual performance. With a portable IR thermal printer, flue gas readings can be printed on the spot and attached to service records. It helps validate the technician's performance findings.

"It's pure marketing," said Tom Santa, president of Santa Energy, Bridgeport, Conn. "The proper use of modern tools can do wonders to improve your image.

"Today's consumer is used to high tech. Show them your printed results and explain what they mean. This is a tremendous way to build confidence and trust."

Publication date: 09/13/2004