Abstract: An apparatus and method for monitoring the operation of a heating, ventilation, air conditioning and/or refrigeration (HVAC/R) system includes a first computer located on or near the HVAC/R system and a plurality of sensors positioned to sense various operating parameters of the HVAC/R system. The sensors communicate the sensed parameters to the first computer. When the first computer detects a condition of the HVAC/R system that requires attention, based on parameters sensed by the sensors, the first computer communicates with a second computer located remote from the first computer and transmits a message related to the condition.