Patent attributes
A heater includes a burner housing that houses burners for combusting a fuel and air mixture into heated gas. Heater tubes each extend from and return to the burner housing for radiating heat. The heater tubes each have an inlet end and an outlet end with the inlet ends in communication with the burners for receiving the heated gas from the burners. A collector box is disposed in the burner housing in communication with the outlet ends of the heater tubes for receiving the heated gas from the heater tubes. A fan is in communication with the collector box to move the heated gas from the burners to the collector box. The outlet ends of the heater tubes are adjacent each other at the burner housing and each of the inlet ends of the heater tubes are spaced in different directions from the outlet tubes at the burner housing.