Abstract: A system for controlling the flow and combustion of natural gas and/or liquid propane in a ventless fireplace. The system utilizes an ODS pilot in combination with a burner, an electronic control module, a gas control valve, an igniter, and a flame rectification sensor. When the pilot is lit, an ionized flame is provided and the current of the flame rectification sensor is rectified, providing a signal to the electronic control module to maintain the delivery of gas to the pilot and main burner via the gas control valve. When the oxygen level within the fireplace falls below a predetermined level, the flame at the pilot becomes unstable and this prevents the rectification of current at the flame rectification sensor, signaling the electronic control module to cease the flow of gas the burner and pilot via the gas control valve.

Abstract: A direct vent gas fireplace has an angled flue pipe that can be directed horizontally out of the back of the fireplace or vertically out of the top of the fireplace, a baffle that conceals an exhaust opening in the back of the fireplace heat chamber from view while minimizing shielding of the firebox panels surrounding the fireplace heat chamber, and an air column that directly channels venting air from the flue pipe downwardly across the back panel of the firebox to an air inlet adjacent to the bottom of the firebox.

Abstract: A fireplace has a firebox with a controllable outside air vent to provide a source of cooler air for mixing with and modulating the temperature of the air heated by the fireplace. The air vent is vertically formed between a combustion chamber and a surrounding shell so that a convective current causes the air to flow therethrough and pass over the top surface of the combustion chamber to keep it cooler than otherwise possible with heated room air. Convective currents in another air duct formed between the shell and the combustion chamber circulates room air around the combustion chamber to transfer heat to the room air. The warmed outside air and room air mixes in a plenum above the fireplace prior to entering the room, thereby modulating the temperature of the heated air and permitting it to burn without excessively heating the room. A damper regulates the flow of outside air into the air vent, as desired.