I am getting intermittant flame stoppage after furnace runs sometimes days sometimes hours with error Open High Limit Device. This is a Trane TDE080A945K2 about 11 years old. I get continuity on the HLI to HLO circuit. I replaced flame sensor and hot surface ignitor, and filter. When the flame stops the blower keeps blowing, blowing cold air. I checked the connectors to the control board on the HL circuit and the ignitor circuit they look OK. When I disconnect then reconnect the furnace seems to run OK for a while again sometimes days sometimes just 10 minutes. Does this seem like a control board problem, or something else?

Any luck in getting this problem solved? I have the same model and problem. Our furnace was installed in November of 1999, so it too is 11 years old. I wonder if this model had a defective part or two in the manufacturing process. We had the controller board replaced over 5 years ago, and it was over $200 to have this work done back then. I would grateful if you have solved your problem and could let me know what your solution was. Thanks.