I turned up the water heater to watch the burner ignite, and when done, turned the heater back down. When the burner turned off, the pilot flame went out. I lit it, and turned the burner on and off a few times, watching the pilot while doing so. Each time the burner turned-off, the pilot flame would waiver, quite a bit, and that's why the pilot turned off the first time I turned on the burner. I must admit, I've really never watched a pilot flame before when the burner shuts down, so is this normal? If so or if not, what would cause the pilot flame to waiver on burner shut-down, almost like someone was blowing on it?