Granted Patent
Utility
US 5,239,838 · App. 07/762,440
Heating and cooling system having auxiliary heating loop
Inventor:
Steven N. Tressler
Patented Case
View Patent ↗
Granted: Aug 31, 1993
Filed: Sep 19, 1991
Inventor
Steven N. Tressler
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.