dryer heats for approximately 4 minutes then stops heating. When first starting the dryer I get 0 volts ac across the flame sensor switch (closed), igniter glows and flame kicks on. after 4 minutes flame goes out and I have 118 volts ac across flame sensor switch(open). after about 1 minute I have 0 volts across the flame sensor switch, igniter glows but no flame. Ignitor glows for about 10 seconds then goes out and there is 118 volts across the flame sensor switch(open). this repeats approximately every minute after. I watched it do this three times before I shut the dryer off. I feel this is a problem with the burner system, possible coil? It looks like I have to take the front of the dryer off to get to the burner. How do I do that. Please help!

Purchased and installed valve coil kit. dryer working again. It was fun trying to figure out how to get to the gas burner valve though. Had to figure out how to take the whole front of the dryer apart to get to the coils.