Have set the thermostat settings at 225 for high and 100 for low maximum setting is 275 heats up blower comes on but does not stay on long enough maybe 45 seconds to a minute. Stove is hot enough that it should stay on but doesn't. I have toyed with the settings don't know what to do. P.S. I have bent a wire so I can hold the thermostat on until it starts to blow cold air what's the problem with it? Is the thermostat bad?