Last spring I had a Carrier Infinity 96 Furnace and Infinity thermostat
installed. Recently the furnace has been randomly shutting down with
the "Call contractor" message on the display. The furnace will restart
and the message disappears if I turn the power to the furnace off then
back on. This happens about once per week. Another problem is that
the thermostat randomly display the "Replace or clean filter" message
despite the fact that I just changed the filter. I tried turning off
the Accessory Maintenance Pop-Up Message for Clean Air Filter message
but that message pops-up randomly anyway.

I also had a new air conditioner installed at the same time and
experience no problem with the thermostat this past summer.

My contractor has replaced the Thermostat (which is still under
warranty) last week but the problem just reoccurred. Now that the
weather is below freezing I am fearful of leaving the house for long
least my pipes freeze. Any suggestions would be appreciated.