CT30 Stat w/ C-Wire Goes into OFF Mode after Power Failure - Solved!

[billslovin]

I have two CT30 stats both connected with a C-WIRE and I've been testing some power outage scenarios. If I turn off my HVAC power the stats loose power (as expected), however when I turn the HVAC power back on, the stats go into the OFF position instead of going back to the mode they were in prior to the outage.

Is this by design? Seems like a flaw since this means that if there is a power outage, the pipes in the house could freeze.

Anyone have any thoughts. Can Homeseer be setup to periodically broadcast the current state to the thermostat so it gets reset in the event of an outage?

[GaryDN]

do you have batteries in the stats? I have lost power and mine go back to the same settings as before.

how long did you leave the power off?

[billslovin]

I don't have batteries in the stat. Is that recommended even when a C-WIRE is connected?

[GaryDN]

yes because during a power failure you will lose your settings.

[billslovin]

OK, I put batteries in the stat and confirmed that the previous state is maintained when I turn off the HVAC power. Still seems a bit unusual to me that the thermostat doesn't store the previous state in some sort of Non Volatile Memory, but it is what it is.

[GaryDN]

the battery is the non volatile memory


we expect a lot from technology don't we, it would be nice if homeseer could reset it for us as well.

[chewie]

I have one of the Trane thermostats that I got from Radio Shack, it does not take batteries and uses a C-wire, is this type of behavior what I should expect from that stat? Or should it retain its settings in NVRAM that will show when power comes back up?

[billslovin]

I wouldn't assume any behavior. You should run a test to be certain. If it doesn't remember the prior state then you've got an issue on your hands becuase if you are on vacation and you loose power, your temperatures might not be maintained properly.