Abstract: A liquid to gaseous fuel conversion system relating to the conversion of a liquid-fuel combustion heater to a combustion heater using at least one gaseous fuel. The system includes a gas train, which includes a gas inlet configured to receive gaseous fuel from at least one gaseous-fuel source, a gaseous-fuel burner assembly adapted to replace a liquid-fuel burner of the liquid-fuel combustion heater, the gaseous-fuel burner assembly including a gaseous-fuel nozzle configured to inject the gaseous fuel into a moving stream of air to form a moving air-fuel combustion mixture, the gaseous-fuel nozzle having a set of nozzle turning vanes configured to induce a vortex within the moving air-fuel combustion mixture. Components of the system are arrange to use the original mounting points of the liquid-fuel burner assembly.