[ANSWERED]: Thermostat going haywire

So this happened:

May 30, 2015, 9:00:19 PM
Received INSTEON "HVAC Thermostat" on (button 1)
Trigger HVAC A/C Start Time
Received INSTEON "HVAC Thermostat" cool setpoint changed to 20.0
Received INSTEON "HVAC Thermostat" cool setpoint changed to 20.0
Received INSTEON "HVAC Thermostat" cool setpoint changed to 20.0
Received INSTEON "HVAC Thermostat" heat setpoint changed to 14.0
Received INSTEON "HVAC Thermostat" heat setpoint changed to 14.0
Received INSTEON "HVAC Thermostat" heat setpoint changed to 14.0

HVAC A/C Start time just records the time it started into a variable.

Didn't realize it until we were headed upstairs at 1030pm to go to bed...I said, "Honey, it's cold in here" and I thought I'll just check...and sure enough the house was down to 71 (cool setpoint is supposed to be 74 after 7:30pm). So I reset power to the HVAC, and then changed the setpoint back to what it should be.

Is there any way to figure out what is going on here? Is the thermostat going haywire? Or did Indigo command the setpoint? I have a Venstar T1800 thermostat.

This is kooky and a little scary...worried that someone could be inside my server. We've been having a LOT of screwy behavior the last few days (not just with the thermostat).

Best,
Phil

[matt (support)]

Hi Phil,

I don't believe it is a hacker. Indigo isn't transmitting the commands, but just reporting is received the new values from the module (via INSTEON).

It could be the thermostat has a glitch (or firmware bug). Another possibility would be if you have an INSTEON link from another module (SwitchLinc, KeypadLinc, etc.) to the thermostat that is recalling those setpoint values. Lastly, the thermostat might be (or have been) in program mode and it is running its own internal temperature schedule.

Not sure which of those is causing it. I'd suggest keeping an eye out for it to see if there is a pattern when/how it occurs.

Matt,
Thanks. Nothing else is linked to the thermostat, and it is never in program mode (definitely not programmed to drop to 20 or 14 degrees F), so I'm guessing it was a glitch in the thermostat. We did have some power fluctuations a few days ago, so maybe that's the cause of all the funkiness.
Will keep an eye and report back if any more weirdness.
Best,
Phil

[jay (support)]

Just FYI - I had a weird brownout before a power outage last week which cause 5 Insteon devices to freak out. One of my Venstar thermostats did something very similar - it got switched into program mode with completely messed up setpoints. I don't know if the Insteon thermostat adaptor did something wonky or the thermostat itself did it, but given that 4 other Insteon devices needed factory resets and resyncs I'm leaning towards it being a very adverse reaction to a longish brownout before the power cut off completely.