Five Considerations That Will Help You Obtain An Accurate Analysis Of Post-Combustion Gases In Boilers

Operating a boiler efficiently requires establishing a delicate balance between too little and too much combustion air. While an experienced operator may develop a feel for the proper amount of combustion air that should be introduced into the burners, that is no substitute for objective analysis of the combustion process. One means of determining the efficiency of a boiler's air/fuel mix is by analyzing the post-combustion gases through the use of one or more specialized instruments. Known as flue analysis, these measurements provide important readings useful for adjusting combustion air input. However, the uninformed use of flue analysis can lead to inaccurate readings and cause more harm than good. That's why you should keep in mind the following five considerations that will help you obtain accurate measurements:

Match gas analysis instruments with fuel type

The type of fuel being used makes a difference on the specific kinds of gases output as well as concentrations. Many gas analyzers permit users to adjust settings to match the fuel source, so be sure to take advantage of this capability if your analyzer possesses it. If your analyzer doesn't have adjustable gas settings, obtain an analyzer that matches the specific fuel type used in your boiler. Analyzers are available for monitoring natural gas, propane, heating oil, wood and other forms of energy sources.

Use reliable sampling techniques

Combustion gas readings should be taken from the gas flow stream at predetermined points. Avoid taking readings near joints or bends in vent stacks, and be sure that probes are inserted fully into the access point to prevent outside air from contaminating the readings on your instruments. In addition, do not expose analyzers to heat; keep units away from hot spots on or near duct work, steam pipes and other surfaces since heat can cause false readings or instrument failure.

Keep your smoke density monitor clean

If your boiler contains a smoke density monitor, be sure it is frequently cleaned. Since smoke density monitors use a beam of light passed across the gas flow, they are sensitive to anything that might obscure lenses and cause skewed readings. That makes it critical that smoke density monitors be kept free of accumulations such as soot and ash. Fortunately, cleaning a smoke density monitor usually involves the simple and easy task of wiping down sight glasses. Keep in mind that smoke density monitors contain both a transmitter and receiver and that both units will need to be cleaned; the presence of contaminants on either one can provide false readings.

Don't monitor gases with condensation inside the sampling area

As water vapor condenses while the boiler cools, its presence can cause the gas readings to be inaccurate. That's why you should always be sure to measure gases during periods of normal operation, not when the boiler fire is operating at a reduced level. Waiting too long to sample gases after a boiler fire reduction will lead to false readings, so be sure the temperature levels inside the boiler are optimal. If you notice the presence of condensation, raise the temperature of the boiler until the liquid evaporates.

Clean and replace sensor probes on a regular basis

After being exposed to heat and combustion particles, the temperature probe for your gas analysis instruments is going to quit working at an optimum level. Damage will often occur gradually, so keeping a record of readings is important for establishing baselines for equipment monitoring purposes. Visibly inspect the probes of your instruments regularly; if you notice the probe is dirty, try cleaning it first with a high concentration of isopropyl alcohol. If cleaning does not provide adequate correction of suspect readings, then replace the probe assemblies as needed.

Now that you know how to properly test the combustion gases in your boiler, if you need to purchase a new boiler for your business, then contact a company like Nationwide Boiler.