Which statement is true regarding inshot burners?

Inshot burners are designed with specific features that help optimize their performance for heating applications. The characteristic that highlights their design is that they indeed require a separate flame carryover channel. This feature is essential as it allows for the proper transfer of the flame from the burner into the heat exchanger, enhancing the combustion process and ensuring that the system operates efficiently.

Inshot burners function by drawing air directly into the burner through a nozzle, mixing it with gas at the point of combustion. The flame carryover channel ensures that this flame can travel safely and effectively into the heat exchanger, minimizing the risk of flame blowout and providing consistent heating.

The other options do not accurately represent the nature of inshot burners. They do not necessarily have a universally high efficiency rating, they can operate on various gas types, not just liquid propane, and they are not typically found in electric furnaces, which utilize electric resistance heating rather than combustion. This context clarifies why the requirement for a separate flame carryover channel is a defining aspect of inshot burners.