Atwood On Off

My 95 coach has the original Atwood heaters. Both have been working well. Today, my front one started behaving strangely. When the thermostat called for heat, the fan would start as usual and the burner would ignite as usual. However, after burning for maybe three seconds, the burner would turn off (the fan would keep running). Anyhow, I cycled it maybe five times or so and now it's working perfectly. I was thinking the limiter switch or the circuit board but was surprised when it began working again. Ideas? Thanks.
jor

Arghhh... just cycled on again and no fire. Darn!