I have 2 White-Rodgers thermostats, Type No. 1F86-244, which individually regulate 2 furnaces. I switched the 1st one on to run the furnace this fall. Iit did start and run the furnace, it failed to reach the selected temperature. I changed the batteries in this thermostat. It did not improve it's performance. I later started the 2nd furnace and it is reacting the same. Originally they were running about 2 degrees lower than the selected temperature. It has gotten worse. Is there anything I can do?