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Unfortunately, with the decision to purchase a programmable thermostat
comes the obligation to learn how to program that new thermostat. It's
like buying a clock radio and going online to find someone to help you
figure out how to set the alarm time on it.
Every digital thermostat is different, and you need to find a 1-800
number in the literature that came with it to determine how to program
Also every thermostat, whether digital or analog will have an "heat
anticipator" setting that needs to be set. A heat anticipator in an
analog thermostat is nothing more than a small electric heater that
fools the thermostat into thinking the room is warmer than it really is.
The reason for having a heat anticipator is that some forms of heating
have a long residual heat time. For example, cast iron baseboard
radiators will continue to convect heat into the room long after the
boiler shuts down. The purpose of the heat anticipator is to heat the
be-metallic coil inside the thermostat to fool it into thinking the room
is warmer than it really is. That shuts off the boiler early so that
the temperature doesn't overshoot the set point be as much as it
Another reason for having a heat anticipator in a thermostat is that the
thermostat is typically centrally located in the house or zone being
heated, whereas the radiators or heating ducts are located around the
perimeter of the house or zone being heated. If the boiler were to
continue firing until the temperature at the thermostat was at the set
point, the room temperature between the thermostat and the perimeter of
the house or zone being heated would be well above the set point.
Consequently, the heat anticipator is set to shut the heating system off
early so that the average temperature in the house or zone being heated
fluctuates about the set point.
Now, your literature will tell you to add up all the amperage draws on
all of the thermostats zone valves and everything on the 24 volt AC loop
the thermostat is on to determine the heat anticipator setting. As of
now, I have yet to find anyone who can explain why the heat anticipator
setting should be equal to the current draw of the thermoatat 24 VAC
loop. You're best bet is to simply set the heat anticipator setting
lower if you find that your furnace is cycling too frequently, and to
set your heat anticipator setting higher if you find too long a time
between your furnace cycling on and shutting off.