| 摘要 |
A gas heater has a burner disposed in confronting relation to an upper panel of glass and an air supply/discharge fan for supplying combustion air to the burner and discharging combustion exhaust gases from the burner through a porous body. The burner combusts a fuel gas at a predetermined air-fuel ratio which is determined to provide a good combustion efficiency of the burner to provide an effective heating area on the upper panel which is located within a circle having a larger diameter L10. Alternatively, the burner combusts the fuel gas at an air-fuel ratio representing richer air than the predetermined air-fuel ratio, lifting combustion flames off the burner. The lifted combustion flames are absorbed by the porous body to provide a smaller effective heating area on the upper panel which is located within a circle having a smaller diameter L20. <IMAGE> |
