I have a lennox g50uh(x) series gas furnace. I replaced the thermostat, but still having the problem with the furnace not reaching set temp. It is set at 68 but it will go down to as low as 55 and will not reach the 68. It does turn on and the furnace seems to be working. I had someone look at the furnace and he states that it is working properly. His recommendation was to change the battery in the thermostat. I did that, no success. That is when I purchased a new one and still no success. It will reach as hi as 61. I have no anticipator on the back of the hunter 44110 thermostat. When it was as low as 55 I turned the fan to on, but it did not come on. I then went to the furnace and turned it off then back on. It started working but did not reach the temp. It does come on during the day, but once again does not reach the set temp. Help! It has gotten very cold here in Atlanta.