Abstract: A method and system for modifying a conventional furnace are disclosed whereby greatly improved furnace operating efficiency is obtained. The temperature of the structure, the outside temperature, and the temperature of the heat exchange fluid are measured. The rate of flow of fuel to the furnace is adjusted as a function of the difference between the outside temperature and the desired temperature of the structure. The fuel rate flow is further adjusted as a function of the difference between the furnace's heat exchange fluid temperature and the actual interior temperature of the structure. A further adjustment to fuel rate flow is effected as a function of the difference between the temperature of the interior of the structure and the desired structure temperature. A novel gas pressure valve is also disclosed for altering the rate of gas flow to the furnace.

Abstract: A valve is disclosed which receives a fluid such as gas at an input port and varies the fluid pressure at the output port in response to an electrical control signal. In one embodiment, a magnet-coil combination responds linearly to a control current to vary the bias on a fluid restriction device to thereby modify the pressure of the fluid at the outlet. In another embodiment, a flexible bellows transmits the force generated by the magnet-coil combination to the fluid restriction device.