No matter what type of fuel is used, soot will quickly accumulate in boiler firetubes. As much as 1/8" of soot can build up in only two weeks. This buildup reduces boiler efficiency and wastes dollars. Soot has five times the insulating value of asbestos. The heat transfer loss in a dirty boiler rises tremendously as the layer of soot builds up. Boiler efficiency can be monitored through stack temperature readings. For every 40F rise in stack temperature, fuel consumption increases by 1%. An increase in stack temperature is an indication of dirty tubes and a signal to clean the boiler tubes with a Power Tube Cleaner PCR-1X