I don't know much about HVAC because I haven't had many problems till now. My thermostat (honeywell T8001C) display goes blank and the heat will not turn on.

I've tried flipping the breakers in the garage. That won't work. Any ideas?

Some thermostats take a battery. Others go dead if the little fuse on the control board blows.

My thermostat went out last night. The sign on the thermostat says "low" and below the word low is the # 8 and the letters AE does this mean it needs new batteries. I changed the batteries but they were not new ones, they were ones out of a old flashlight. Would I need to get new batteries and re-set the thermostat?