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Combustion Analysis: The Key to Furnace Efficiency

combustion analysis
Gas furnaces boast an incredible degree of durability, and they can easily go years without significant issues. Unfortunately, this fact often leads homeowners into believing that their furnace doesn't require professional attention at all. Yet as time goes on, subtle changes within a furnace may cause its efficiency to drop off, resulting in higher and higher heating bills.
Furnace technicians can accurately measure the efficiency of a furnace through the technique known as combustion analysis. If would like to improve your knowledge about how this cutting edge technique can work for you, read on. This article will outline the basics principles of combustion analysis, as well as the ways it can promote more efficient furnace operation.

Combustion Analysis

At the heart of a gas furnace lies the combustion chamber. Here, burners ignite the gas flowing in through the gas valve, producing the heat that will warm your home. The combustion process also results in the formation of exhaust gases. These substances consist of chemical byproducts of combustion, often stemming from naturally occurring impurities in the gas itself.
When certain byproducts are present, it may indicate that gas has not been combusted completely. This, in turn, may tie back to other factors, such as an improper air-to-fuel ratio in your furnace. If a technician can recognize incomplete combustion, they can often resolve the issue by tuning-up or cleaning certain components of your furnace.
Combustion analysis allows technicians to identify problems with your combustion. This technique involves using sophisticated instruments in order to measure the precise byproducts — as well as the levels of those byproducts — in the exhaust gas coming out of your furnace. This information then allows them to make the necessary changes to promote more thorough combustion.

Tools of Combustion Analysis

Traditionally, HVAC technicians performed a combustion analysis by first using a special probe to take a sample of the flue gases and then having that sample analyzed at a lab. Today, combustion analysis can be performed much more accurately and quickly using a tool called the digital combustion analyzer.
A digital combustion analyzer has two distinct components: a flue probe and an analyzer. As its name suggests, the flue probe is placed inside of the furnace's exhaust flue. The technician then turns the furnace on. As exhaust gases begin to flow up into the flue, the probe will instantaneously capture and record the levels of various substances.
The probe then transmits this information to the analyzer — a handheld tool with a screen on which the technician can view the data being collected by the probe. Key substances being measured involve all of the following:
  • Oxygen
  • Carbon dioxide
  • Carbon monoxide
  • Nitrogen oxides
In addition, the flue probe will also collect information about the temperature of the exhaust gas.

Furnace Tune-Up

The information gathered by a combustion analyzer allows a technician to locate potential problem areas. They can then make appropriate changes and assess the results in real time. Such changes generally involve two things: gas pressure and air entry speed. Altering both of these things allows a technician to dial in the best possible air-to-fuel ratio.
The results of a combustion analysis may also lead to other types of repairs. For instance, improper fuel pressure may stem from the build-up of gunk on the gas nozzle. In that case, adjusting the gas pressure would only act as a temporary solution. Only by tackling the underlying problem can true efficiency be increased.
Getting the most from your furnace means having it inspected and analyzed on a regular basis — even when nothing seems to be going wrong. For more information about having a combustion analysis performed, please don't hesitate to contact the HVAC experts at Peterson Heating and Cooling.