30HXA246RZ-650KA...does it have a battery that maintains the memory in the main board? we have been told that if the battery is not changed every 3-4 years then the main board will have to be sent to Carrier to be reprogrammed...any truth to this? if there is a battery that needs to be regularly replaced...where is it?

we tried our local carrier office but they were not very helpful.

thank you!