Today I did the combustion fan upgrade to my Alaska out in the garage which is power-vented. In the process I decided to test the fume switch by applying heat to the inside where the flume switch comes thru. Nothing! Upon further inspection the tube was so plugged up with gunk that it wouldn't respond. I got in there with an awl and compressed air and got it cleaned out. After cleaning it worked as it should.
Maybe most are aware and clean regularly but I wasn't and wanted to share with those that may not be. I bought the stove used and installed last winter with a new power vent but never thought to check the operation of the fume switch.