overrides that are not allowed due to control algorithms on the site controller should be flagged as u201c override denied u201d in a status register at the time an acknowledge is sent to the rtu if a change request is discovered during a 5 30 second poll the site controller will then merge and process change requests from all rtus send an acknowledge by clearing change request register and send updates to all rtu 39 s with permissions in an embodiment during this merge process the site controller evaluates all the override requests and if multiple requests are received to override a common thermostat 39 s set points the maximum set point is used and sent to the respective thermostat fig4 is an illustration of a flow chart depicting a change request cycle in the site controller fig5 a and 5 b are illustrations of flow charts depicting a screen flow of screens s1 s11 of an rtu as shown in fig5 a when the u201c menu u201d button is pressed on screen1 the system displays screen s2 which includes a number of choices to the user including u201c tstats u201d u201c lighting u201d and u201c shutdown u201d when the u201c tstats u201d button is pressed the user is shown screen s4 which provides a list.