Abstract: A microprocessor control determines, in the course of initiating a heating cycle, whether the blower is operating in the continuous mode, and if it is, the control prompts the blower to be turned off prior to the ignitor being turned on. In this way, the blower and ignitor are never on at the same time and the instantaneous total current draw is limited to thereby reduce the occurrence of burned out fuses or circuit breaker trips.

Abstract: A two-stage gas furnace control system automatically shifts into a high fire only mode if, in two consecutive low fire heating cycles a limit switch is tripped to indicate that a gas valve is stuck in a high fire condition. In this way, continued operation is allowed to proceed in a safe manner. Provision is also made to lock out the system from further operation if, while in the high fire only mode, the limit switch is tripped in a predetermined consecutive number of cycles or if, while in a preemptive low fire only mode, the limit switch is tripped.

Abstract: An economizer has a single sliding door which leads to the indoor section from both the outdoor air inlet and the return air inlet, with the two inlets being separated by a divider baffle. The sliding plate is movable from its fully closed position, wherein the indoor section is shut off from the outdoor air inlet, to a fully opened position, wherein all of the air passing to the indoor section is coming from the outdoor air inlet and the opening between the indoor section and the return air inlet is closed. The sliding plate can also be placed in intermediate positions wherein a mixture of return air and outdoor air is provided to the indoor section. The economizer is so designed that it may be applied to either a down discharge or a side discharge unit without any change to the economizer structure itself.

Abstract: In a refrigeration system having a compressor driven by a variable speed motor, the refrigerant flow volume through the expansion device is controlled by way of a solenoid driven piston which alternately opens and closes the orifice, with the duty cycle of the solenoid being controlled such that the time period in which the orifice is open is proportional to the speed of the motor. A bypass channel is provided in parallel around the orifice such that a minimal flow is provided to thereby share the load with the modulating orifice and act to dampen the movement of the solenoid piston.

Abstract: A sliding lock mechanism is mounted behind the front wall of the chassis, and associated openings are provided in the front and side walls of the chassis to respectively provide operator access to the lock mechanism and allow it to be reciprocally moved so as to extend through the side wall opening to engage a flange surface of the cabinet to thereby lock the chassis in its installed position. A fastener is also provided in the front wall opening to secure the locking member in its engaged position.

Abstract: Provision is made for sensing when the gas valve relay contacts are welded, or stuck, in the closed position and for responsively turning off the inducer motor when that occurs. This in turn causes the pressure switch to open to thereby cut off the power to the gas valve and cause it to move to the closed position.

Abstract: In a centrifugal machine for a refrigeration or air conditioning system and including a casing, an impeller, a variable width diffuser assembly leading from the impeller, and a plurality of vanes received through respective complementary-shaped openings in a movable wall member, there is provided a sealing means in the openings between the vanes and movable wall member for preventing leakage of fluid through the openings, thereby increasing the operating efficiency of the machine.

Abstract: An evaporator condensate pan has a condensate trap incorporated therein to thereby eliminate the need for the installation of the separate component. A well structure is provided in the bottom wall of the condensate pan and an additional depending wall structure is provided such that the depending wall, together with a side wall of a well, define a passage way which retains a column of water for preventing the flow air into the condensate pan while allowing the flow of condensate out of the pan. Provision is made for such a combination discharge drain and trap in either a side or bottom wall of the condensate pan.

Abstract: A furnace having the capability of operating its blower continuously is provided with means for automatically shutting off the blower at the beginning of a heating cycle and for resuming the operation thereof only after a predetermined time has elapsed to allow the heat exchanger to heat up to a temperature that exceeds the dew point of the flue gas, to thereby reduce the occurrence of cold spot corrosion in the heat exchanger. Provision is also made, in a two speed blower system, for operating at a lower speed during continuous mode and heating cycle operation, and for operating at the higher speed during the cooling cycles.

Abstract: A sleeve assembly and an air conditioning unit are disclosed for mounting the air conditioning unit in a through the wall application. The sleeve assembly includes duct connections, drain connections and electrical connections such that during construction of the building all the connections of the air conditioning unit are made to the sleeve. Thereafter, the air conditioning unit may be engaged into the sleeve to complete the installation.

Abstract: The intermediate partition of a room air conditioner is provided with a downwardly extending slot in its upper edge such that installation and removal of the motor, with its attached fans, can be easily accomplished without removal of the partition. A filler plate is provided for insertion into the slot after the motor has been installed into its mount in the outdoor section.

Abstract: A method of controllably charging a heat pump system with refrigerant until adequately charged for the cooling mode of operation, including checking the outdoor ambient temperature, injecting sufficient refrigerant to sustain safe compressor operation, operating the compressor at higher or lower rates depending upon the detected ambient temperature level and determining when to halt charging by monitoring indoor coil inlet and suction temperature differences in the heat pump system.

Abstract: A self-correcting control system and method is provided for a furnace to correct certain operating conditions that exceed normal limits. Upon sensing insufficient air flow as a function of the pressure drop across the heat exchangers, the control system and method cause the inducer motor to increase in speed, thereby to increase the flow of combustion air. Similarly, upon sensing that the flow of air to be heated exceeds a predetermined temperature, the control system and method will increase the speed of the air blower to increase the flow rate of air to be heated through the furnace, thereby resulting in lowering the temperature of the air to be heated below the predetermined temperature. Upon sensing a gas flow leak through the gas regulator, the control system and method will recycle the gas regulator to properly seat a gas flow control valve therein. If none of the self-correcting features correct the particular occurring problem, the control system and method will shut down the furnace.

Abstract: The control system of an induced draft furnace includes a provision for turning on the inducer motor when a flame is sensed outside of the normal sequence of a heating operation. In particular, if the thermostat is in the off position when a flame is sensed, the inducer motor is turned on to ensure that sufficient combustion air is provided to the burner so as to forestall the occurrence of flame roll outs in the event that the gas valve is stuck in a closed position.

Abstract: The discharge air sweep mechanism for an air conditioner is provided with slippage in its drive linkage such that the position of the vanes can be manually adjusted when the drive motor is turned off, or if the vanes become jammed during normal air sweep operation, the drive motor can continue to operate without damage to the mechanism. In one form of linkage, frictional engagement is provided by a pair of arms that are biased together with engaged member disposed therebetween, with the engaged member being allowed to slide between the arms upon the occurrences of either of the above mentioned conditions. Vane stop means is provided to automatically recalibrate the relative positions when normal air sweep operation is resumed.

Abstract: The fan drive motor mount of a room air conditioner is mounted on the base pan with the edge of one U-shaped member fastened directly to the base pan and with the side walls of the other U-shaped member partially overlapping the side walls of the first member and having means to secure the two members in an adjustable manner such that the first and second members can be appropriately spaced so as to accommodate any of various sized motors.

Abstract: A control panel door is mounted to the front grille panel of an air conditioning system in such a way as to allow it to be opened by first pivoting it to an oblique position and then sliding it to a position behind the front grille panel. Provision is made for easily assembling the door to its supporting track structure while at the same time preventing its accidental disassembly when opening the door. Provision is also made for holding the door in the closed position.