I have the wireless Insteon thermostat and have read and followed many of the forum posts here regarding the various issues and bugs within this device.   I have setup my thermostat to monitor the water temperature in my hot tub.  I have the external temperature sensor soldered directly to where the internal temperature probe was as outlined by others in this forum as a way to get temperature updates to be sent to my ISY.

 

I also have it connected to an external power source to get continuous updates.  While I do get updates pretty quickly now that it's connected to the 5V power source, I have noticed that I only get updates every 2 degrees of temperature change instead of each temperature change. I saw this mentioned as the behavior it follows when on battery, but mine is not and I still only get two degree updates.  (See attached log)

 

Is this just a built-in limitation of this thermostat or is there something I can tweak to get it to actually send more rapid updates?

 

Thanks.

No.

 

I found and suspect about a 1.5 degree report limit.

 

Try to position your sensor more into the hot water supply stream to make your sensing act more like the old mechanical thermostat with  a "predictor". This was a heater element that came on when the heat was on and attempted to shut the furnace off before the wave of heat finally got to the thermostat. This was an attempt to eliminate the highs and lows in your heating cycles.

 

The readings will not change but if you are feeling the extremes the above may work for you to help smooth out the temperature fluctuations.