Sellers Engineering Company was founded by Kelly Sellers in Chicago in 1931 when new industries were looking for ways to take advantage of natural gas energy. Over 10,000 large volume water heaters were produced in record time by Sellers for Army installations throughout the United States. Many of these installations are still being used today. Eventually, this design would be developed into the current forced draft systems used today. The next step in the evolution of boilers with forced draft combustion would be to seal the combustion chamber for pressurized firing. Once again, Kelly was a leader in the development of this technology.