I have noticed that sometimes when I go out to the barn in the mornings after a batch burn the night before, that the blower/fan is sometimes still running. The temperature shown on the controller display will be anywhere from 100 to 130F. The boiler circulator will be off. I never noticed this last year, but I was doing more continuous burning only when it was very cold outside. Sometimes the controller shows the "add fuel" message that I expect to see. Any ideas on why my fan will sometimes stay on?