Abstract: A fuel control system, parts therefor and methods of making and operating the same are provided, the fuel control system comprising an ignition unit for igniting fuel issuing from a burner, and a flame detecting unit for detecting flame at the burner, the flame detecting unit comprising a sensing device for receiving an electrical signal caused by flame rectification at the burner, and an output device for cycling the signal to the sensing device in an on and off manner in each cycle of operation of the output device, the control system having a modulating unit for modulating the on time and the off time of the output device in each cycle of operation thereof.

Abstract: A fuel control system, a control unit therefor and methods of making the same are provided, the system comprising a control unit that reduces the length of the warm-up time period of an igniter in subsequent successive burner cycles in which ignition is successful until the control device detects an increase in the length of the flame detecting time period in that particular successive burner cycle over the length of the flame detecting time period on a previous burner cycle at which time the control device then increases the length of the previously reduced warm-up time period a certain amount.

Abstract: A method of operating a relay includes shifting, by a predetermined time increment each time the relay coil is energized, the time in the sine wave of the applied AC power source at which the relay coil is energized. The method further provides for similarly shifting the time in the sine wave at which the relay coil is de-energized. When applied to a system having two relays, the method includes providing such shifting to both relays and further includes providing a predetermined time delay between the time one relay is de-energized and the other relay is energized.

Abstract: A control system for controlling the operation of an air conditioning compressor and method of making the same are provided, the system comprising a thermostat switch and a high pressure switch arranged in series with a compressor switch across two sides of a power source whereby the thermostat switch and the high pressure switch must be in a closed condition thereof with the compressor switch also being in a closed condition before the compressor can be turned on, the system also comprising a low pressure switch that is arranged so as not to be in series with the other switches across the two sides of the power source and a microprocessor having means operatively associated with the low pressure switch to monitor the condition thereof.

Abstract: A control system for controlling the operation of an air conditioning compressor and method of making the same are provided, the system comprising a thermostat switch and a high pressure switch arranged in series with a compressor switch across two sides of a power source whereby the thermostat switch and the high pressure switch must be in a closed condition thereof with the compressor switch also being in a closed condition before the compressor can be turned on, the system also comprising a low pressure switch that is arranged so as not to be in series with the other switches across the two sides of the power source and a microprocessor having means operatively associated with the low pressure switch to monitor the condition thereof.

Abstract: A gas burner control system includes an electrical resistance igniter, gas valve means, and a microcomputer and related circuitry. The microcomputer and related circuitry control energizing of the igniter in such a manner so that the igniter, after successive ignition attempts, will eventually, in response to a learning routine, be heated to a desired ignition temperature. The microcomputer and related circuitry also control operation of a circulator blower in response to burner flame and provide for numerous checks on the integrity of system components.

Abstract: A gas burner control system includes an electrical resistance igniter, gas valve means, and a microcomputer and related circuitry. The microcomputer and related circuitry control energizing of the igniter in such a manner so that the igniter, after successive ignition attempts, will eventually, in response to a learning routine, be heated to a desired ignition temperature. The microcomputer and related circuitry also control operation of a circulator blower in response to burner flame and provide for numerous checks on the integrity of system components.

Abstract: A programmable electronic thermostat is provided for controlling operation of a multistage heating apparatus comprising a heat pump and auxiliary heat. A salient feature is a program which provides for economical recovery from a setback temperature. The program includes logic which determines, at the beginning of the recovery time, whether any or all of the auxiliary stages will be temporarily locked out and thus prevented from being energized. This determination is based on a characteristic which is dependent upon the heating demand that is presently being placed on the heating apparatus. The program also includes logic which determines, near the end of the recovery time, whether any or all of the locked stages are to be unlocked. This determination is based on the magnitude of the difference between the temperature existing at the time of determination and the temperature desired at the end of the recovery time.