Emerson Electric Co.
HVAC system mode detection based on control line current

Abstract:

A monitoring system for monitoring a heating, ventilation, and air conditioning (HVAC) system of a building includes a monitoring server. The monitoring server is configured to receive an aggregate control line current value from a monitoring device. The aggregate control line current value represents a total current flowing through control lines used by a thermostat to command the HVAC system. The monitoring server is configured to determine a commanded operating mode of the HVAC system in response to the aggregate control line current value. Operating modes of the HVAC system include at least one of an idle mode and an ON mode. The monitoring server is configured to analyze a system condition of the HVAC system based on the determined commanded operating mode.