Abstract: Retractable stairs for mounting in an exterior doorway of a recreational vehicle are provided with a spaced apart stringers and a tread extending between the stringers. Spaced apart straps are connected to upper ends of the stringers and are pivotally mounted to a floor in an interior space of the recreational vehicle to allow movement of the stringers and the tread through the exterior doorway between a retracted position stowed within the recreational vehicle and a deployed position outside of the recreational vehicle. A threshold plate is positioned between the straps and is fixed against movement during the pivoting movement of the straps. Locking latches extend outwardly from the stringers and are positionable for engaging a jamb of the exterior doorway for releasably securing the stringers and the tread in the retracted position. Extensible support legs are mounted on the stringers and extendable downwardly below the stringers to engage a ground surface for supporting the retractable stairs.

Abstract: A single-package, wall-mount air conditioner is provided with an economizer unit having a pair of vertical conduits for delivering fresh outside air to a pair of blowers and a damper system that can be selectively positioned to open and close the conduits. The damper system also opens and closes return air recirculation openings through which return air is delivered to the blowers. When the air conditioner is operating in an economizer cooling mode, the return air recirculation openings are partially or completely closed and some or all of the return air is discharged outwardly and upwardly from the air conditioner in a manner to impede any entrainment of the discharged return air with the fresh outside air that is entering the air conditioner.

Abstract: A single package, wall mount air conditioner including a cabinet, an evaporator coil assembly, a condenser coil assembly, and a theft deterrent system. The theft deterrent system including metal straps securing the coil assemblies to the cabinet and impeding their removal from the cabinet. The straps having boxed cross-sections and being attached by specialty fasteners requiring a non-standard tool to remove, wherein the heads of the fasteners are shielded to only permit the axial access required by the tool. The theft deterrent system further including a sensor configured to monitor a condition of the air conditioner, wherein the condition is indicative of an attempt to remove the coil assemblies from the cabinet, and to communicate an alarm signal through a speaker or to a remote monitoring station if the condition occurs. The sensor may include one or more of a plunger-type switch, a vibration sensor, or a refrigerant monitoring sensor.

Abstract: An air conditioning system for cooling an enclosure includes an air conditioner and a control system for triggering an economizer cycle of the air conditioner. The control system determines an electrical load of equipment in the enclosure, calculates a maximum acceptable outdoor temperature at which the economizer cycle may be operated based at least partially on the electrical load, receives data representative of an actual outdoor temperature, and initiates the economizer cycle if the actual outdoor temperature is equal to or below the maximum acceptable outdoor temperature.

Abstract: An air conditioning system for cooling an enclosure includes an air conditioner and a control system for triggering an economizer cycle of the air conditioner. The control system determines an electrical load of equipment in the enclosure, calculates a maximum acceptable outdoor temperature at which the economizer cycle may be operated based at least partially on the electrical load, receives data representative of an actual outdoor temperature, and initiates the economizer cycle if the actual outdoor temperature is equal to or below the maximum acceptable outdoor temperature.

Abstract: An air conditioning system for cooling an enclosure includes an air conditioner and a control system for triggering an economizer cycle of the air conditioner. The control system determines an electrical load of equipment in the enclosure, calculates a maximum acceptable outdoor temperature at which the economizer cycle may be operated based at least partially on the electrical load, receives data representative of an actual outdoor temperature, and initiates the economizer cycle if the actual outdoor temperature is equal to or below the maximum acceptable outdoor temperature.

Abstract: A lock-out circuit for preventing over-heating of a recreational vehicle heating system includes a temperature limit switch and a lock-out relay. The temperature limit switch is electrically coupled with the heating system and is operable to open when its temperature exceeds a threshold temperature and to reset and close when its temperature drops below the threshold temperature range. The lock-out relay has a contact electrically coupled with the temperature limit switch and a high impedance relay coil electrically coupled with the heating system in parallel with the temperature limit switch. The temperature limit switch and the lock-out relay remove substantially all power to the heating system when the temperature limit switch opens and re-establish power to the heating system only after the temperature limit switch has reset and voltage is at least temporarily removed from the lock-out relay.

Abstract: A method of controlling operation of a pair of two-stage air conditioners. The method monitors a temperature of an area served by the air conditioners; activates a first stage of a first or lead air conditioner when the temperature rises above a first set point temperature; activates a first stage of a second or lag air conditioner when the temperature rises above a second set point temperature; activates a second stage of the first air conditioner only if the temperature remains above the second set point temperature beyond a first selected time period; and activates a second stage of the second air conditioner only if the temperature remains above the second set point temperature beyond a second selected time period.

Abstract: A method of controlling operation of a pair of two-stage air conditioners. The method monitors a temperature of an area served by the air conditioners; activates a first stage of a first or lead air conditioner when the temperature rises above a first set point temperature; activates a first stage of a second or lag air conditioner when the temperature rises above a second set point temperature; activates a second stage of the first air conditioner only if the temperature remains above the second set point temperature beyond a first selected time period; and activates a second stage of the second air conditioner only if the temperature remains above the second set point temperature beyond a second selected time period.

Abstract: An apparatus and method for controlling the maximum stroke of a linear compressor is provided. The shorting of the normal supply voltage of a compressor to ground is used to detect overstroking. A plurality of transistors are electrically coupled to the control circuit that is electrically coupled to a linear compressor. When the compressor's stroke exceeds it maximum stroke marked by the refrigerant barrel of the compressor making physical contact with the armature, a signal is received by the control circuit. The control circuit processes this signal and sequences the transistors to return the extended stroke of the compressor to its maximum stroke.

Abstract: A single package wall mounted HVAC unit comprising a cabinet assembly including a primary cabinet subassembly, a back panel subassembly adapted to close the open back of the back panel subassembly, and cabinet connection means for removably attaching the primary cabinet subassembly to the back panel subassembly so that the back panel subassembly can be attached to the wall of a structure and then the primary cabinet subassembly can be positioned on and attached to the back panel subassembly. Also disclosed is a blower mounting arrangement for selectively mounting the air circulation blower within the cabinet subassembly in different positions to attenuate the blower noise transmitted to the conditioned space. An interlock is disclosed for the control box to prevent the control box cover from being removed without disconnecting the HVAC unit from the power supply.

Abstract: An electrical driver (10) for a linear electrical motor which drives a linear refrigerant compressor (11) that has a resonant frequency includes a sensor (22) for measuring the magnitude and polarity of the back EMF of the electrical motor at the beginning and/or end of the stroke of the compressor (11). A control circuit (12) analyses the measured back EMF to determine whether the driver frequency is higher or lower than the frequency of the compressor (11) and then adjusts the frequency of the driver (10) to or closer to the resonant frequency of the compressor (11).

Abstract: A single package wall mounted HVAC unit comprising a cabinet assembly including a primary cabinet subassembly, a back panel subassembly adapted to close the open back of the back panel subassembly, and cabinet connection means for removably attaching the primary cabinet subassembly to the back panel subassembly so that the back panel subassembly can be attached to the wall of a structure and then the primary cabinet subassembly can be positioned on and attached to the back panel subassembly. Also disclosed is a blower mounting arrangement for selectively mounting the air circulation blower within the cabinet subassembly in different positions to attenuate the blower noise transmitted to the conditioned space. An interlock is disclosed for the control box to prevent the control box cover from being removed without disconnecting the HVAC unit from the power supply.

Abstract: An air conditioner is provided which is mounted on the rooftop of a recreational vehicle to provide cooling of an interior space within the vehicle. The air conditioner has a single motor that mounts both a centrifugal fan and an axial fan for rotation about a vertical axis. The centrifugal fan is positioned within an evaporator compartment that contains an evaporator for providing cooling of an air stream drawn therethrough. The centrifugal fan draws warm air from within the interior space of the vehicle into the evaporator compartment where it passes through the evaporator and is then drawn axially through a center opening into the centrifugal fan. The cooled air is expelled tangentially from the centrifugal fan and is redirected downwardly by a surrounding scroll and delivered to the interior space for cooling thereof. The axial fan is positioned in a condenser compartment where it draws outdoor air through a condenser for heat exchange therewith.

Abstract: The present invention relates to an air conditioner apparatus comprising a housing including top and side walls, and presenting an air inlet and first and second air outlets, the first and second air outlets being disposed on different ones of the top and side walls. A blower assembly including a central axis about which the blower assembly is supported for rotation relative to the housing, the blower being in fluid communication with the air inlet and the first and second air outlets for forcing air under pressure from the air inlet to the first and second air outlets. A first removable air outlet cover assembly for blocking the air under pressure from being discharged through the first air outlet, the first removable air outlet cover assembling including a first flow control structure for directing air under pressure toward the second air outlet.