We have 7 year old Frigidaire front-load GLGQ2152ES gas dryer (NG). Auto dry cycle will start fine - ignitor nice and hot, gas valve opens, flame starts, dryer starts cycle and runs - however, randomly, the gas valves will bounce - about 12 to 15 times with flame going on/out and ignitor coming on each time as normal to light gas. Dryer will still finish cycle and dry clothes. No error codes, replaced coils to be sure, machine clean, replaced flame sensor. Took out gas valve swapped with spare, same issue, no dirt obstructions on gas pre-filter in valvle body. Any ideas?

Simon,
Bounce - the valves chatter - open/close very rapidly sounds like clickety-clack-clickety-clack for about 15 to 20 cycles. I have since put dryer in diagnostic mode, forced "on" run with heat and while doing this mode, let the gas ignite, then disconnect the flame sensor - the flame will stay on and run for some time with no gas valve chatter, however, the flame sensor was brand new and shows full continuity when checked. I checked all wiring - good and took out front control circuit - looked clean, no burns, reconnected after cleaning. Could still be control board and apparently a switch exists at motor - I saw a brown armature sticking down from black plastic switch body, but seemed in order.???

Simon, I did take your advice and changed out control board. Seconds later.... still excessive gas valve opening/closing. In the meantime after changing flame sensor, and checking ignitor (good), I also swapped out the gas valve body itself. The control board did not solve the problem. So, in spite of continuity checks, jumper wires around control board and motor to check hot lead and neutral, I am missing something here. Isn't the last item in the circuit here the motor with some sort of centrifugal switch? HELP!!!