Batteries in thermostat were changed nine days ago. Did not turn thermostat off. Last night indicator read error and have no heat. Live in portsmouth va.

Turn the heat off, remove batteries, and reinstall properly, set thermostat, then turn the heat back on. See if that resets the thermostat. Likely the error code and shut down was due to the thermostat being interrupted during a running cycle.

If it does not, please let us know.