My 8 year old Trane Model tuh2d120a9v5va furnace is not giving out heat. The service people are all busy due to the recent storms. Through the little glass viewing window I see red and green flashing lights. The red flashes 4 times, the green 3 times, and these overlap. The panel inside says the 4 flashing red means an open limit switch.
Where do I go from here?
Update: A 1" flat capacitor in the fan control module was fried black and cracked. A new module and $1000 later and the heat works again. Perhaps the power fluctuations due to the storm here caused some spikes that fried the module. I might put a surge protector on the line to the HVAC.