Hello, I am working on a mobile home furnace, it is a Homemiller furnace down flow. The problem i am having is, the blower motor keeps on cycling on and off. when the burners lit the furnace heats up and i can watch the fan limit heat up and turn the blower on then the burners shut off and the fan continues to run until the fan limit cools down and the blower shuts off, then i can watch the fan limit heat up again without the furnace liting and it will kick the fan back on until it cools back down. it will continue to do this every minute all day long. i have read some post with similar problems but never really nailed the problem. the whole furnace was cleaned, the air flow is good and i adjusted the fan on and fan off settings, i set the cut in at 140 and the cut out at 90. any help would be greatly appreciated.