Heatec manufactures three basic types of water heaters for a wide variety of industrial uses. They have burners that are gas fired. Special versions are available with burners that operate on diesel fuel. Firestorm® is the brand name of their most popular water heater. It is a direct contact water heater that heats water on demand and provides a continuous supply of instant hot water at a constant temperature. It has an extremely high thermal efficiency.
Special versions of the Firestorm heater are available with NSF certification for food processors. They also offer a helical coil heater for heating water. It is virtually the same as a thermal fluid heater, except it heats water as it is pumped through its helical coil to an external storage tank or reservoir. The water does not normally recirculate through the heater.