For giggles I pulled up a picture of my thermostat heat set point between July 15th and the present. I was surprised to see spikes up to 255 degrees and down to 16 degrees (see image below). What's with that?

 

I only control the t-stat from the ISY but my programs are pretty simple. Plus, for the most part, seem to be operating my HVAC correctly.

 

I did experience recent behavior where my t-stat was turning itself off and my ISY locked up this month. I also called Smarthome and because my t-stat dongle was v2.0 and the ISY locked up, they are going to send me a upgraded plug-in. So my hope is these spikes could be related to the old plug-in going/gone bad.

For giggles I pulled up a picture of my thermostat heat set point between July 15th and the present. I was surprised to see spikes up to 255 degrees and down to 16 degrees (see image below). What's with that?

 

I only control the t-stat from the ISY but my programs are pretty simple. Plus, for the most part, seem to be operating my HVAC correctly.

 

I did experience recent behavior where my t-stat was turning itself off and my ISY locked up this month. I also called Smarthome and because my t-stat dongle was v2.0 and the ISY locked up, they are going to send me a upgraded plug-in. So my hope is these spikes could be related to the old plug-in going/gone bad.

 

Glad, I'm not the only one.

Let me know if you make headway, I'm too lazy at the moment to diagnose.

good luck. I have been working this problem for over a year. It reared its ugly head in the Summer of 2010 when the system set my Cool setpoint to 16 degrees. this is a second home and we are not around much in the summer. I caught it after 2 days. It was 110 outside and 60 degrees inside. luckily no damage was done to the air conditioner, just my pocket book. I have since created a program that catches these set point changes and resets the Thermostat to acceptable levels. I worked with Smarthome for a number of months and have passed info to the UD team on and off but no one can figure out what is causing this. its still happening and I cannot find any kind of pattern. I have even had conversations with my security company to see when they probe hoping it may occur at the time of a spike.