How do I change the batteries in my Honeywell T8602 thermostat?

how do I change the batteries in my Honeywell T8602 thermostat? They don't even tell you how in the owner's manuel (other than that I need 3 AA alkaline batteries). I CANNOT find a battery door to open ANYWHERE! Help!How do I change the batteries in my Honeywell T8602 thermostat?Pull the thermostat up from the bottom and the batteries will be on the underneath side of the thermostat.How do I change the batteries in my Honeywell T8602 thermostat?I don't think thermostats have batteries ???? why do you think you need a battery