HVAC controller with user-friendly installation features facilitating both do-it-yourself and professional installation scenarios

A method of determining a heating, ventilation, and air conditioning (HVAC) system configuration by a thermostat, the method comprising:

• determining which of a plurality of first HVAC connectors and which of one or more second HVAC connectors have wires inserted therein, wherein:
• the plurality of first HVAC connectors are configured to receive a corresponding plurality of first HVAC control wires from the HVAC system, each of the plurality of first HVAC connectors being associated with a single possible HVAC function;
• and
• the one or more second HVAC connectors are configured to receive a corresponding one or more second HVAC control wires from the HVAC system, each of the one or more second HVAC connectors being associated with a plurality of possible HVAC functions;
• causing to be displayed, on a user interface, graphical icons representative of each of the plurality of first HVAC connectors and each of the one or more second HVAC connectors, wherein graphical icons corresponding to HVAC connectors with wires inserted therein are visually distinguished from graphical icons corresponding to HVAC connectors without wires inserted therein;
• causing to be displayed, for any of the one or more second HVAC connectors having wires inserted therein, a display of at least some of the plurality of possible HVAC functions that can be associated with each of the one or more second HVAC connectors;
• receiving input, for any of the one or more second HVAC connectors having wires inserted therein, selecting ones of the plurality of possible HVAC functions to assign to each of the one or more second HVAC connectors;
• determining an HVAC system configuration based on which of the plurality of first HVAC connectors have wires inserted therein, and based on any input selecting ones of the plurality of possible HVAC functions to assign to each of the one or more second HVAC connectors;
• and
• operating, if possible, the thermostat at least in part according to the determined HVAC system configuration.

A thermostat comprising:

• a processing system;
• a plurality of HVAC connectors configured to receive a corresponding plurality of HVAC control wires;
• a connection sensing circuit coupled to the plurality of HVAC connectors and configured to provide an indication to the processing system of whether a wire is inserted for each of the plurality of HVAC connectors;
• and
• wherein the processing system is configured to:
• receive an indication from the connection sensing circuit when an HVAC connector in the plurality of HVAC connectors has a wire inserted therein, the HVAC connector being associated with a plurality of possible HVAC functions;
• cause to be displayed, the plurality of possible HVAC functions on a user interface;
• receive input selecting one of the possible HVAC functions for the HVAC connector;
• and
• operate the selected HVAC function through the HVAC connector.