Air conditioner control

摘要

A control system for a central air conditioner. The air conditioner includes an outdoor condensing unit including a refrigerant compressor, an indoor evaporator unit, an indoor thermostat responsive to the indoor temperature for controlling the air conditioner, and a control system for protecting the air conditioner and indicating to the user certain malfunctions in the air conditioner should they occur. The malfunction indication may be by means of signal lights and a manually operable reset control is provided permitting the user to reset the control system. The malfunction indicator and reset control are disposed adjacent the thermostat for facilitated determination of the system operating condition. The control system includes an improved control portion for starting of the compressor motor which is arranged to prevent operation of the system in the event of a low power supply voltage condition. The control system provides a minimum "Off" reset time before permitting the air conditioner to automatically attempt to restart regardless of the condition causing stopping of the air conditioner. The control system further includes a current sensing control which determines the compressor motor current a preselected time after the closing of the compressor motor switch and is arranged to discontinue operation of the compressor motor in the event the current is above a preselected high value. Clock pulses are used to facilitate operation of the current sensing control. Improved accuracy in the timing of the control system is obtained by means of coordinated use of clock pulses and R-C time delays. The control is arranged to prevent operation of the compressor drive motor when the temperature of the system adjacent the compressor is alternatively below a first preselected temperature or above a second preselected temperature. The control includes a second sensor for sensing the temperature conditions at the condenser which is arranged to prevent operation of the drive motor when the sensed temperature is above a preselected high temperature and to adjust the control parameters of a sensor provided for determining the temperature adjacent the compressor.