There are two types of under-fired charbroilers. One type allows the radiant heat source to heat a radiant to a cherry red color. The radiant, in turn, broils the food product. The other type of charbroiler uses a heating source above or below to heat lava rocks or ceramic briquettes. The rocks or briquettes then distribute the cooking heat more evenly than would the heat source alone.
Some manufacturers use both methods to increase the efficiency and reduce preheat energy loss.
The broiler grate is adjustable to both level and tilted positions. Typically, the charbroiler is designed for the rear two-thirds of the grate to be hotter than the front section. Many standard models have grease troughs fastened to each blade in the cast iron top grates to provide an avenue for excess fat runoff and reduce flaming. Excess residual fat drains into a large grease drawer located in a cool zone for disposal. The charbroiler, like an open range-top burner, consumes energy at a constant rate, which is dependent on the temperature control setting.