What are you using to compare ambient room temp, to the temp that the thermostat shows? Is the thermostat in a room that gets full direct Sunlight, or anywhere that it may have the sensor blown on by a fan or vent.
You can adjust the temp on the CT-30, by pressing Menu, then Calibrate. You can also adjust Swing & Differential on that screen. I have mine set at 1.5 for Swing, and 3.0 for Differential, due to I have a two stage furnace. The Operation guide for the thermostat can be found at. http://www.radiothermostat.com/documents/CT-30-Operation-19apr10.pdf
Just make sure you are taking room temperature with a known good calibrated thermometer. If you wish. You can contact a local HVAC service company that has calibrated instruments, that will tell you if your thermometer you were using is bad, or the placement of your thermostat is bad.
Most homes will have the thermostat in a hallway, so that it is in what is called a "Dead air" space. That means that it would not have any direct Sun on it, or have air blowing on it from a register.
You can adjust the temp on the CT-30, by pressing Menu, then Calibrate. You can also adjust Swing & Differential on that screen. I have mine set at 1.5 for Swing, and 3.0 for Differential, due to I have a two stage furnace. The Operation guide for the thermostat can be found at. http://www.radiothermostat.com/documents/CT-30-Operation-19apr10.pdf
Just make sure you are taking room temperature with a known good calibrated thermometer. If you wish. You can contact a local HVAC service company that has calibrated instruments, that will tell you if your thermometer you were using is bad, or the placement of your thermostat is bad.
Most homes will have the thermostat in a hallway, so that it is in what is called a "Dead air" space. That means that it would not have any direct Sun on it, or have air blowing on it from a register.