Apparatus to sense and control compressor operation in an HVAC system

An HVAC system comprising:

• an evaporator, a condenser, and a compressor connected in a closed loop refrigerant system;
• and
• a control system to control the closed loop refrigerant system, the control system comprising:
• a controller having a plurality of output connections capable of being electrically connected to a compressor, the compressor being electrically connected to the controller by at least one output connection;
• a load sensing circuit and a processor electrically connected to at least two of the plurality of output connections of the controller, the load sensing circuit being configured to generate a load signal for the processor for each of the at least two output connections connected to the load sensing circuit in response to a load being present on the at least two output connections connected to the load sensing circuit;
• the processor being configured to determine a type of compressor based on load signals from the load sensing circuit;
• and
• the processor providing instructions to configure the controller to operate with the determined compressor type in response to the type of compressor determined by the processor.