I have had a Honeywell FocusPro TH5000 installed professionally for about 3 months. It was working fine until 2 nights ago. It is set on 68. When it gets below that & the heat turns on, it will continue to run long after it has reached the 68 temp (hours, even all day). I have to bump it down to 67 to get it to stop. I have looked in the manual & online but didn't see much.
I have a Tempstar heat pump. Any suggestions?

You need to adjust the anticipator. On analog t-stats the anticipator is an adjustable arm that rides on a coil of thin wire to adjust the resistance. It's right in front of you when you remove the cover to t-stat. The anticipator provides a small amount of "false" heat to make the t-stat cycle off in heat (In cooling another anticipator is a high value resistor.) to keep it from staying on after the temperature has been reached in heat, or to bring it on in cool mode. If you have a manual t-stat move the arm clockwise until it cycles like you want it. One thing you need to look at is where the t-stat is located. If mounted on an exterior wall it will never cycle right, for example. Has anything changed lately to change airflow around t-stat? If you have a digital t-stat the way to set the anticipator is in the instructions, or it's automatic, as most digitals are.