At times during the day my gas burner doesn't try to come back up to the set temperature on the upstairs or downstairs main thermostat.
I'll hit the up button a couple of degrees but no change. Then when I flip the thermostat switch to off and back on again, the unit fires up for heat maybe 10 minutes or so. Sometimes I have to do that twice for it to stay on but it still doesn't get to the set temp. But at 2am its working again correctly.
I've replaced the batteries on them and swapped the thermostats as well. Sometimes it works for days.