Can not get the furnace to come on. The temp is 72 on the DHM110 Lux thermostat. I push the up button and 73 flashes three or four times then it goes back to 72. What is wrong?????? The low temp for the save is 68. Just changed the batteries and hit the reset button, but it was doing this before I changed the batteries and reset it. That's why I did the above.