First, thanks to everyone with your help on my previous posts. As I get to know my system, I run into all sorts of unexpected bumps. Went away for the weekend and set the temperature to hold (should have used vacation hold, but didn't realize until reviewing the manual) while we were gone. When we got back, one of the thermostats (Waterfurnace labeled TP32U03) gave me a weird lockout error when I returned (see attached), presumably from returning to temperature, and I wasn't able to unlock or reset the trip. Eventually, I powered down the airhandler circuit that was running the thermostats/intellizone. Temperature seemed to be at the proper level. Any idea what would cause this kind error (so I can avoid it in the future) and how to reset the lockout from the thermostat?