Long time reader first time writer. I have been looking into the portage and main 250 and I have a question concerning the primary and secondary air system. There is a motor that opens/closes a damper to the opening of the secondary air (the air that goes into the gasification chamber). How is this motor controlled? Is it by a thermostat and if so, where is it or is it by a timer? I imagine that the primary air is controlled by the water thermostat and the fan turns on when the water is calling for heat. The motor keeps the damper shut until the heat in the chamber reaches X or a timer that times out and the motor opens the damper to allow the air into the chamber thus igniting the gases. Can anyone help me out with this?