Abstract: An open fireplace with an air distribution system for heating one or more rooms and including a heat exchanger and an electric fan for forcing air through the heat exchanger thence through the air distribution system. Incorporated into the fireplace system is a flow control apparatus at the heating air outlet end of the heat exchanger providing fluid communication of heating air into the distribution system or through a by-pass communication back to the immediate area in which the heating air inlet to the heat exchanger is located. The flow control device includes a damper which is positioned in response to a heating air condition such as flow or temperature to divert heating air from the distribution system into the by-pass to avoid excessive air temperatures in the distribution system.