I have a 25 year old non-catalytic Blaze King Princess. I remember the thermostat working fine when it was new. But now it doesn't seem to work at all. The inlet air vane moves freely when I touch it. If I run a hair dryer on the bi-metallic coil, it moves quite a bit. Like maybe 30 degrees. But as the stove warms up or cools down, the air vane does not move at all. Any idea what could be going on here? Thanks.