Carrier Furnace. My furnace blower stays on after shutdown. Keep getting a code 33 which says flame rollout switch is open. How do I bypass them or tell if they are bad? Had control board replaced afew months ago. If I let the system sit a couple of hours, it will usually reset. Please help.

Roll-out switch's require a manual reset on the limit switch itself. If it is resetting itself it must be a bad switch or electrical connection, you might need a pro, the switch's are pretty cheap.