Best Way to Adjust a Thermostat's Heat Anticipator

If your furnace is short cycling, or turning on and off frequently, it may be because you need to adjust your thermostat's heat anticipator. This is fairly simple task to accomplish and the article below will tell you, step-by-step, how you can do this.

Start by removing your thermostat's cover. Make sure that it is level. If the thermostat is not level, the mercury switch will not work right. In the middle of the thermostat, you will find a small disc that has calibration makes on it. The word "longer" will probably be on it also. This disc is fastened to a lever arm and indicator, which relates to the calibration marks. This is the adjustment arm for the heat anticipator.

If your furnace is cycling too often, you need to move the heat anticipator's adjustment lever closer to the longer setting, by one calibration mark. If it is getting hotter than the set temperature or never reaching the set temperature, you need to move the lever away from the "longer" setting by one mark. Once you have made the appropriate adjustment, let the furnace run and the temperature stabilize for about two to three hours.