Lennox Manufacturing, Inc.

Keith A Temple

Oved W Hanson

In accordance with the present invention, a method of determining refrigerant charge level in a space temperature conditioning system includes the steps of establishing a relationship between at least one selected system operating parameter and refrigerant charge level, independent of ambient temperature conditions; measuring the selected parameter(s) while the system is in operation; and using the established relationship and the measured parameter(s) to determine the refrigerant charge level. In one embodiment of the invention, both condenser subcooling and evaporator superheat parameters are measured and the predetermined relationship between charge level and each of these parameters is used to determine the actual refrigerant charge level.

Method of determining refrigerant charge level in a space temperature conditioning system

In accordance with the present invention, a method of determining acceptability of a selected condition in a space temperature conditioning system is comprised of the steps of perturbing the system while it is in operation by changing operation of at least one component thereof; sensing a change in a first operating parameter of the system in response to the changing step and generating a control signal in response to the change in the first operating parameter being greater than a predetermined limit; sensing a change in a second operating parameter of the system during a period beginning with the perturbing step and ending with the control signal; comparing the change in the second operating parameter with a reference corresponding to an acceptable condition; and determining acceptability of the selected condition in response to the comparing step. In a preferred embodiment, the method according to the present invention is used to determine acceptability of refrigerant charge level in a space temperature conditioning system.

Method of determining acceptability of a selected condition in a space temperature conditioning system

Apparatus is provided for sampling gas in operative association with a combustion appliance, such as a furnace. The combustion appliance includes a first conduit through which combustion air is supplied to the appliance and a second conduit through which gas heated by the appliance is discharged from the appliance. The sampling apparatus includes a third conduit communicating between the first and second conduits and a gas sensor operable to sense a selected gas in the heated gas present in the third conduit. Operation of the appliance creates a pressure difference between the first and second conduits to draw a sample of heated gas from the second conduit into the third conduit, so that no mechanical device, such as a pump, is needed to transport the sample of heated gas to the gas sensor. A temperature sensor is provided for sensing temperature of the gas in the third conduit to verify gas flow in the third conduit. If the temperature sensor does not sense at least a predetermined increase in temperature during a predetermined period of appliance operation, it indicates insufficient gas flow in the third conduit for sampling purposes. The gas sampling apparatus may be used to detect products of combustion leakage in combustion appliances as well as to measure the concentration of a selected gas, such as carbon monoxide.

Growing community of inventors

Pittsburgh, PA, United States of America

Keith A Temple