Wood-burning unit, centrally located in new house, is awesome--can almost heat the whole place all winter. In its second winter, noticed that higher temp in firebox was needed before blower started. Now, blower doesn't come on at all. I know where thermostat is in firebox, behind a firebrick in the sidewall, but don't know if I can (or should) fool with it, or even access it. Any suggestions? I'm handy, but neither engineer nor electrician.