The fuel line into our crawl space to the furnace used to form a plug in the wall several times a winter in Fairbanks. At -40 or so. Had to turn on the propane stove and open the oven door to get some heat until we could thaw out the plug. It was a quick, though cold fix. lol
And every so often when I was a kid we would get a rock or piece of metal in the auger from the coal hopper to the furnace. It would break the cotter pin to space the auger and motor, and by the time we realized it was getting really cold in the second floor, it was a while to warm up. Dad used to keep nails by the auger to replace the cotter pins.
