I have a Goodman ac/heat system. I recently installed a new Honeywell RTH2300 thermostat. Now, for some odd reason, the thermostat will not control the temperature correctly. If the heat is set t0 come on at 72 degree, the thermostat will not tell the heat to kick on until the temperature in the house drops down to 68 degrees or so. When the heater does come on the temperature may reach 76 or 78 degrees before kicking back off again. It over (and under) shoots terribly. I have the wires connected to this new thermostat exactly as I did on the old one. That is: Red wire to Yellow post. Yellow wire to red post. Ground to G and White wire to white post.