What I am trying to do is see if the sensor.water_heater_alarm_last_boot_time stops checking in with HA. So I guess that would remain static unless it check in but I need to compare that to the current time which should be constantly changing.
I found the below post which talks about “the function now() is not an entity; i.e., it does not cause state_change events.” Which I think may be the problem.
So I’ve been trying to tweak the code to use something like (as_timestamp('sensor.date_time') with no luck.