Warren S. Johnson

Warren Seymour Johnson was an American college professor who was frustrated by his inability to regulate individual classroom temperatures. His multi-zone pneumatic control system solved the problem. Johnson’s system for temperature regulation was adopted worldwide for office buildings, schools, hospitals, and hotels – essentially any large building with multiple rooms that required temperature regulation. To manufacture and market his system, Johnson established the Johnson Electric Service Company which eventually became Johnson Controls.

Johnson was born in Leicester, Vermont on November 6, 1847. His family moved to Wisconsin three years later, eventually settling in Menomonie, Dunn County, Wisconsin. It appears that he had only limited formal educational training – but supplemented his knowledge with self-study of scientific subjects. He worked for a time as a printer, surveyor, schoolteacher, principal and school superintendent. In 1876 he obtained a teaching position at the State Normal School in Whitewater – now known as the University of Wisconsin–Whitewater. Five years later he was named professor of natural science.

Johnson had an inquisitive mind and was particularly interested in electricity. In 1883, he developed a thermostat, which he deployed at the State Normal School. He called the instrument an "electric tele-thermoscope" in the patent application. It was a bi-metal coiled thermostat with a mercury switch, which could be used to ring a bell to alert the fireman to open or close the heating damper. While not the first bi-metal thermostat, Johnson received a patent for the device and interested William Plankinton, heir to the Plankinton Packing Company, to provide financial backing to manufacture the device.

The Johnson Electric Service Company was established in 1885 in Milwaukee, Wisconsin. Johnson’s most notable contribution to temperature control was the automatic multi-zone temperature control system – a pneumatic system that used a bi-metal thermostat to control air flow through a nozzle and thereby operate a pilot regulator. The amplified air signal from the regulator was then used to control a steam or hot water valve on a heat exchanger, or to control a damper of a forced air system. He received a patent for the system in 1895.

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