I have a builder installed Goodman GDS80904BHA that is approximately 5 years old. Recently, when the furnace completes a heat cycle, approximately 1-2 minutes after the cycle has completed and after the blower shuts down, the blower will come on again for anywhere from 30-90 seconds. There is no call for heat during this "second" cycle. The blower just seems to be recirculating air. The furnace has never behaved in this manner before. The furnace was professionally inspected and cleaned less than 12 months ago and I have replaced all return air filters. I'd like to correct the problem before something breaks when it is really cold.