Without breaking the thermostat, its been a few years since I replaced the battery and it is all plastic

I have the same thermostat, and I have the user manual for it.
The manual says: "Batteries are not required. During power interruption the internal NEVERLOST(TM) memory stores programs for an unlimited time".
It also says: " Clcok Backup - In the event of a power loss, the thermostat will keep time for a minimum of 48 hours without external power or batteires."

Are you sure you replaced batteries in it in the past? Sure looks like no batteries in it, according to the manual.

I'm trying to get the "Service Filter" indicator to turn off on mine. I can find no info about this. I've changed the filter.

Also, there is no manual on the Totaline web site for this model. Not even a mention of a PV110.