I have a ashford 30.1. When I run the stove on high (6 o'clock position) will the thermostat close before it over fires? Or does running it at that position over ride the closing of the flapper. The reason. I ask is because I have never seen the flames die down while running on high. But as soon as the adjust the dial the slightest bit down. I hear the click and the flames die down. Is there a way to test the thermostat?