07380588 is referenced by 14 patents and cites 20 patents.

A heat pump type heating and air conditioning system includes a gas furnace or other auxiliary heat source and a thermostat and controller associated with the heat pump and the auxiliary heat source for automatically energizing the heat pump if the auxiliary heat source is inoperative regardless of whether or not the automatic heating mode has been selected or the auxiliary heating mode has been selected by the user of the system. A method of operating a heat pump system with an auxiliary heating source to automatically change from operation of the heat pump to the auxiliary heating source depending on conditions such as outdoor temperature, and to automatically change back to operation of the heat pump if the auxiliary heating source is inoperable.

Title
Heat pump control system and method of operating to provide automatic backup heating modes
Application Number
10/755579
Publication Number
7380588 (B2)
Application Date
January 12, 2004
Publication Date
June 3, 2008
Inventor
Robert W Helt
Tyler
TX, US
Agent
William O Driscoll
Assignee
Trane International
NY, US
IPC
F25B 29/00
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