A system and method to ensure the proper operation of a power supply unit in an electronic device. The electronic device has a chassis with a length and a width that includes one area having electronic components. A system fan is located in the chassis relative to the electronic components to generate air flow in the direction of the length of the chassis through the electronic components. A power supply unit is located in parallel to the system fan relative to the width of the chassis. The power supply unit includes an AC input, a DC output and an internal fan. A controller is operable to control the system fan to reduce the air flow when the power supply unit turns on AC power to the AC input, or wakes up from a cold redundant state and outputs DC power from the DC output.