I have an englander stove model 55-shp10L , I have had it for 3 years and just last week started acting funny. The top auger will work for a complete rotation and then stop for almost 5 minutes and then start turning and then do the same thing so the fire will die down then build back up then die down. After I stop the and turn the stove completely off and then back on it works okay and then stops. Is this a card problem or heat sensor problem?