Installed the RTH2300 but have a problem because the heater will continue going over the programed temperature... ex: programed at 70 F and will continue till going pass 82 F which makes the house too hot... how can it be set up so that the heater will turn off once it reaches 70 F and if the temperature drops below 70 F it will turn back on to reach till 70 F only... thank you

Make sure you did the system setup correctly #9 and all other setup features.

Make sure the hole in the wall for the wires has been sealed behind the thermostat.

Make sure the thermostat is not in a cool draft location.