While the Ecobee thermostat will alert or give you an alarm if the system runs for an extended length of time if the desired temperate is not met, from my experience this tends to be a very broad window and alerts way too late.
I just ran into a situation where my AC system was slightly low on refrigerant, the indoor coil froze up restricting airflow and the system ran for 34 hours continuously before I happened to notice the temp was a bit warm for this area of the house. Part of the problem is the outdoor temps overnight had dropped below to around 70-73F, but since this is a half underground basement during the day when the temps rose, the basement did not warm a great deal, but the humidity was high. So the indoor temperature did not really get much above 2-3 degrees above the typical setpoint for the Ecobee run time alert to be generated.
I would likely to see a user selectable Run Time Alert that a user could set for say 3-5 hours or more to alert me if the system rum time is exceeding a user threshold. Even better would be a notification if for some reason the system runs X% longer than the typical Run Time over the past period of say 24-48 hours. Kind of a in excess or “Running Average Time” over the last 24-48 hours. Or even possibly both.
It is crazy that Ecobee has not implemented some form of Run Time Alert based on Run Time, not Run Time to reach a specific temperature. Just the wasted electricity and wear and tear on the system running continuously for over 24 hours is crazy, not to mention the coil icing up and possibly distorting the indoor coil and possibly causing a crack in the coil.
I was out of town and just returned, but if I had not returned when I did, it is possible the system could have run continuously for days and the compressor may have overheated and failed.
Please consider adding this as a feature to BeeStat with an user Alert.
This could be very helpful