The problem goes like this. Thermostat calls for heat, burner starts and runs for a minute or so and shuts off. After burner shuts off, the blower starts and the burner starts again until the thermostat reaches temp and the burner shuts off blower contiues to run until the low temp limit is achieved. Would this be the fan/limit control? I've tried making changes to the fan/limit on-off points but there is no change.