Gibson/Nordyne/Tappan furnace model #L1RA-090N-16B is blowing cold air constantly and the burners are not igniting. The red light is flashing once. Does this furnace have a manual reset on the limit switch? I've replaced the clogged filter and shut off the furnace power for a few hours, and turned it back on, but the error light is still blinking and the burners are not igniting. If I have to replace the limit switch, I'd like to know the part number as well.