I recently had a furnace and heatpump installed along with a TB8220U thermostat The heatpump should come on when the outside temperature is 34degrees F But the thermostat reads the outside temperature as being 10degrees F lower than actual temperature so the heatpump doesn't come on until the outside temperature is above 45degrees F. The company that installed the heatpump says they don't know how to correct this and that I should learn to live with it but I didn't spend $10k to have a system that doesn't work. Have they used the wrong sensor with the thermostat? Can it be a faulty sensor and how can I test it? The sensor does work because if I apply heat the reading rises but it is always 10 degrees out. I am using a Fluke digital meter for testing my readings of actual temperature are correct Could it be the wire gauge? I see in the manual it calls for 18ga but the wire appears to be 20 or 22ga. The wire length is about 100ft