31. Within the preheating region, heat is again convectively transferred from the solid structure to the gas. 32. "The preheating of the flexi-cracker begins today, " a Lagoven spokesman said. 33. Place packages on a large baking sheet; let stand 15 minutes while preheating oven to 450 degrees. 34. The oven requires no preheating and can convert to a microwave oven with a touch of a button. 35. When cooking latkes, use a nonstick griddle that has been coated with nonstick cooking spray before preheating . 36. Preheating takes a little longer than usual, but once the desired temperature is reached the heat remains constant.37. Preheating the feedwater reduces the irreversibilities involved in steam generation and therefore improves the thermodynamic efficiency of the system.38. Systems can avoid frosting by modulating wheel speed, preheating the air, or stop / jogging the system. 39. Set an oven rack at the lowest level and place a baking stone or baking sheet on it before preheating . 40. For initial lighting, the vaporiser would be preheating by burning a little oil in a tray beneath the burner.
