I noticed my home gas furnace was turning on, I could hear it running, but it seemed the fan was not blowing the heat out of the heat duct vents...there was almost no air pressure. SO I went downstairs to the furnace, and looked at the red blinking light on my American Standard Freedom 80 furnace, and it showed 4 blinking flashes then a pause, so I looked on the error chart on the front panel, and it said "Open high limit device." I figured I would need to go and find my manual that came with the unit, to see where the "high limit" was located? Anyways, while I was there at the furnace, I figured I would jiggle the 2 electrical connections that connect to the fan housing. I just tried to get the metal on metal connection of the electrical connectors to seat slightly differently. I put the front panel back on, and the system fired up, and this time I could hear the fan running and blowing the hot air. I went upstairs, and yes, the heat vents had blowing hot air. Anyways, in the days before this I had been smelling an odd "electrical burning" smell, like a smell I had smelled before when I had a motor burn out, in some other unrelated tool. I'm just guessing that this smell is related to the new problem with the furnace? The filter was replaced one month ago.
Well, I was wondering if you could suggest some helpful hints and knowledge? I sure would appreciate being able to learn.
What does the HIGH LIMIT device do? Does "open high limit device" error code mean that the device is stuck open?
What do you think the "burning" smell is coming from? Which part would be affected in such a way as to cause this?