US Patent 7607426 Dual fuel heater

In certain embodiments, a dual fuel heater has a pressure regulating device for selectively coupling with a first source or a second source operating at different pressures. The dual fuel heater can also include first and second fuel lines, a fluid flow controller, a combustion chamber and first and second oxygen depletion sensor nozzles. The fluid flow controller is configured to selectively permit flow of fuel to either the first fuel line or to the second fuel line. In some embodiments, the first fuel line is connected to the first oxygen depletion sensor nozzle and the second fuel line is connected to the second oxygen depletion nozzle.