We just bought our Pelpro PP60 and even tho temps outside were still high 60's we got it running and everything worked well. Putting it in comfort mode worked well. It would shut off when the room reached 74 degrees. Now we have had the last few days drop into the 30's at night and 40/50's during the day but even when our room thermometer reads 81 it is not shutting down. Why might it it be doing that? What can i try to stop this problem?