Thermostatic Controls - Honeywell IAQ clock problem driving me nuts

Hi there. I have a YTH9421C1002 thermostat that is not able retain the time on the clock after a power interruption. Every time the power to the furnace is turned off for filter maintenance or after a short power interruption, the clock resets to 1:00. The program settings and date are retained but the clock resets. This could be a problem if there is a power failure while we are away because winters here are cold enough to freeze pipes without heat. Any ideas on what may be wrong with this unit? We moved into this house last year and don't know if this clock issue has always been there. The manufacture date on the T-stat sticker is 07/07.

There is a button cell inside the touch control unit. Would changing that battery help? The manuals don't even mention anything about batteries, so I assume that is not a user replacable part since it requires cracking the case open to reach it. I have this fear that this battery maintains some critical factory programming that would be lost forever if I attempted to remove this battery, turning the T-stat into a brick.

This is the first...

I looked at my manuals, and says nothing about battery... I even searched the net, and nothing came back..

On the back right side, is the red tag been pulled?

I'll take a look at mine to see if there is any way to get to the battery. I'll post back some time tmrw.