I have a intertherm gas heater in my moble home.I started my heater and all was fine up until 2 weeks.it went off and can't relite.I think its my thermocouple the pilot lights but after I hold my set button for a minute like it says to it goes out.I went up on top of my trailer to see if any blockage was in the shaft but all clear.. but I noticed my set lever feels kind of rough I mean it doesn't go from pilot to set very easily.could that be the problem??