Issued Patents All Time
Showing 26–31 of 31 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4974579 | Induced draft, fuel-fired furnace apparatus having an improved, high efficiency heat exchanger | William T. Harrigill | 1990-12-04 |
| 4960102 | Fuel-fired condensing type forced air heating furnace | — | 1990-10-02 |
| 4951651 | Vent overpressurization detection system for a fuel-fired, induced draft furnace | — | 1990-08-28 |
| 4926840 | Pilot gas bypass system for fuel-fired furnaces | William T. Harrigill | 1990-05-22 |
| 4887959 | Gas furnace with improved ignition | — | 1989-12-19 |
| 4729328 | Trap assembly for a condensing fossil fuel furnace | — | 1988-03-08 |