Have HVAC Questions? Ask an HVAC Expert for Answers
OK the low battery indicator is usually for the AA batteries, not the lithium battery. Do you have AA batteries and have you tried replacing them?
This is the back of the RTH7600
Can you attach a photo or see if maybe there is another number besides the 7600?
Thanks for the picture. You should not have to take thermostat this far apart.The lithium battery should outlast the thermostat.Rarely every go bad because they are using very little power.This battery does nothing but hold your program memory. The low bat is referring to the AA batteries that are easily accessible when you unplug thermostat from sub base.