Problem/issue - roll-out / high temp manual reset limit switch, will trip and fan blower will continue to run. Will reset switch and furnace will run for 4-5 days then trip again.
I have checked air flow intake and exhaust, duct air flow cleaned and changed filter. This unit does not have code lights. Any help would be great
Northern Michigan in feb. sub 0's temp.

This trouble shooting guide talks about codes on page 8 http://dms.hvacpartners.com/docs/1009/Public/0D/SM355CAV-01.pdf