I recently installed a new thermostat (manual can be seen here), replacing an old 4 wire analog style. When heating and reaching the desired temp the thermostat shuts off. However, a few seconds later it turns back on for a very brief period then shuts off again. I guess this isn't the biggest problem but I'm concerned it may wear on the system over time. In addition, I noticed that the heat never turns on exactly at the point I set - always two degrees below (IE set to 70 it will turn on at 68). Is this normal?

Thank you.

Sounds like the thermostatic fan control in the furnace. The low temp cutout setting should be lowered a bit. What appears to be happening is that the fan does not run long enough after the burner shuts off to remove all the heat from the heat exchanger. The fan control shuts down, but residual heat warms it back just enough to cause it to run again. I would get that changed because it is adding wear and tear to the blower motor. Or turn the fan ON at the thermostat and let it run 24/7 during the heating season, but that costs extra electricity.