AO Smith GPSH water heater in System Lockout mode but resets itself

gpatalin

My AO Smith water heater goes into lockout mode after someone uses the shower or bath. At first it functions regularly then it starts to ignite again 3 times then goes into lock out mode...after several minutes the water heater resets itself and functions properly until someone uses the bath or shower again...not sure if it's related to how long the shower or bath is used for. It ignites well...I have tried cleaning the ignitor once but did not do it with a emery cloth or sandpaper...not sure. Thanks