Abstract: The present disclosure relates to a multi-circuit heating, ventilation, and air conditioning (“HVAC”) system for use with a first refrigerant in a first refrigerant circuit and a second refrigerant in a second refrigerant circuit. The second refrigerant circuit is fluidically isolated from the first refrigerant circuit. Additionally, a first sensor is operable to detect a leak of at least one of the first and second refrigerants or is operable to measure temperature or pressure from the first refrigerant circuit or the second refrigerant. The multi-circuit HVAC system further including a controller programmed to receive the measurement from the sensor to identify the circuit or circuits that are leaking, to turn off operation of the leaking circuit or circuits, and if only one circuit is leaking, operate only the other of the circuits.

Abstract: The present disclosure relates to a multi-circuit heating, ventilation, and air conditioning (“HVAC”) system for use with a first refrigerant in a first refrigerant circuit and a second refrigerant in a second refrigerant circuit. The second refrigerant circuit is fluidically isolated from the first refrigerant circuit. Additionally, a first sensor is operable to detect a leak of at least one of the first and second refrigerants or is operable to measure temperature or pressure from the first refrigerant circuit or the second refrigerant. The multi-circuit HVAC system further including a controller programmed to receive the measurement from the sensor to identify the circuit or circuits that are leaking, to turn off operation of the leaking circuit or circuits, and if only one circuit is leaking, operate only the other of the circuits.

Abstract: Activation and deactivation of a plurality of heating elements in an electric heating system are separately controllable in accordance with the present invention. Individual heating elements are sequentially activated in response to a demand for heat. A predetermined time delay is imposed between successive activations of the heating elements to allow time to satisfy the demand for heat before another heating element is activated. Normally, the heating elements are also deactivated sequentially in response to a reduced demand for heat, with a predetermined time delay between successive deactivations to allow time to respond to the reduced demand for heat before another heating element is deactivated. A temperature sensor is located in the air discharge plenum of the heating system for sensing the temperature of the discharge air. The discharge air temperature is used to control the operation of the heating elements, a two-speed heat pump, and the "off cycle" of the heating system blower.