Stoves and furnaces – Hot-air furnaces – Liquid or gaseous fuel
Patent
1993-07-23
1994-12-13
Dority, Carroll B.
Stoves and furnaces
Hot-air furnaces
Liquid or gaseous fuel
431 78, F24H 300
Patent
active
053721209
ABSTRACT:
There is disclosed a modification in the control circuitry of a gas furnace having a primary or main limit whereby the primary circuit subsumes the functions of a the secondary or manual reset limit circuit. The control circuit incorporates a microprocessor capable of sensing conditions in the furnace, enabling and disabling the various furnace components. When an overtemperature condition is sensed the furnace is thereupon disabled by a process that executes in the microprocessor and comprises the repeated steps of: sensing if the limit switch is open; determining, in the event that the limit switch is open, whether the limit switch remains open for a period that exceeds a predetermined time interval; incrementing a cycle count in the event that the limit switch has remained open for the predetermined time period; waiting for the limit switch to reset in the event that the incremented cycle count does not exceed a predetermined value, and reinitiating the combustion cycle if the step of waiting was performed; and disabling the furnace in the event that the incremented cycle count exceeds the predetermined value.
REFERENCES:
patent: 3254871 (1966-06-01), Limon
patent: 4296727 (1981-10-01), Bryan
patent: 4403942 (1983-09-01), Copenhaver
patent: 4410132 (1983-10-01), Levine
patent: 4411385 (1983-10-01), Lamkewitz
patent: 4575333 (1986-03-01), Bryant
patent: 4684060 (1987-08-01), Adams
patent: 4702225 (1987-10-01), Heffernan
patent: 4773587 (1988-09-01), Lipman
patent: 4777929 (1988-10-01), Welch
patent: 4789330 (1988-12-01), Ballard
patent: 4891004 (1990-01-01), Ballard
patent: 4982721 (1991-01-01), Lynch
patent: 5027789 (1991-07-01), Lynch
patent: 5135162 (1992-08-01), Holzer
patent: 5169301 (1992-12-01), Donnelly
patent: 5197664 (1993-03-01), Lynch
Swilik, Jr. Robert C.
Whitaker Mark T.
LandOfFree
Safety circuit for furnace does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Safety circuit for furnace, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Safety circuit for furnace will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1187412