Iím having an issue adjusting my heat/cool differential on my Venstar T1800 thermostat. I have a brand new recently installed heat pump. I canít seem to figure out how to set my thermostat so it doesnít turn on after only a difference of two 2 degree. My heat pump turns on and off through out the night constantly. I have followed the instructions as indicated on the manual but canít seem to lock the 4 degree differential which I have chosen. What can I do to reduce the start and stop of my system?