What does the LCD Error Code mean?

Error codes

• E1
  Loss of communication between CT Thermostat and module board. LCD will cycle between E1 and previous mode setting. System will shut down.
• E2
  Open circuit or out of range Indoor Temperature Sensor. Heating and cooling operation will be locked out. Fan operation can continue to operate.
• E3
  Shorted Indoor Temperature Sensor. Heating and cooling operation will be locked out. Fan operation can continue to operate.
• E4
  Open circuit or out of range Outdoor Temperature Sensor (select models). Heat pump operation will be locked out. Air Conditioner, Fan, and Furnace mode of operation can continue to operate.
• E5
  Open circuit or out of range Freeze Sensor. Air conditioner mode of operation will be locked out, but displays the last temperature set-point.