Heating issue

[Huh-me]

Nest Problem

I have recently moved into a newly built home and I want to replace the builder’s stock Honeywell thermostats with Nest thermostats. However, I’m having difficulties with my new Nest thermostats maintaining the house’s temperature. The curious part is that they don’t completely not work, as they’re able to maintain a temperature of roughly 66° when the thermostat is set to 68°.  I have not had any difficulties maintaining temperature with the Honeywell thermostats.

I have a heat pump system with one heat pump on 2 zones, and no auxiliary heat source. 

I have reseated the wires on multiple occasions/attempts and have made sure that the tabs go all the way down.  Finally, I have attempted to switch the O/B settings with no improvement.

 I appreciate any advice to help correct this issue.

[CoolingWizard]

@Huh-me 

When your heat pump is in heat mode and running. Is there warmish air coming out of your vents? if there is warm air coming out of the vents, then your heat pump is functioning. 
Are you describing the system shutting off at 66° and not continue to run until it reaches 68° and satisfies demand?

AC Cooling Wizard

[Huh-me]

It is a little difficult to tell because the registers are in the vaulted ceilings, but it does feel like cooler air is blowing.  It does continue running, and says aux heat even though there is no auxiliary system.  However, it is cold here and if it was only blowing cold air wouldn’t the temperature fall much farfher?

[CoolingWizard]

@Huh-me , 

if the nest thermostat is reporting auxiliary heat been there must be a heat pump installed, and there must be a wire. Also attached to the W2 terminal.  Now the nest thermostat will activate auxiliary heat if the primary heat is not able to heat the face which is sometimes the case when you have a heat pump and the outdoor temperature is extremely cold say below 20°. 
how about taking a moment to upload a picture of your nest backplate showing where the wires are attached and the picture you took of the old thermostat before you took the wires out so I can compare them and see if a mistake has been made.

AC Cooling Wizard

[Huh-me]

Original thermostat

[Huh-me]

The first picture is one I took of our original thermostat.  The second picture is a stock photo, but it is exactly how I wired the Nest including the wire colors.  Again, thanks for your help.

[CoolingWizard]

@Huh-me 

that stock photo is not very good only because the fact that two of the wires are not properly inserted. Make sure that all your wires the bar copper is perfectly straight and flat if you will and fully inserted so that the tab stays down when you let go of it. 

the thermostat to 10 that stock photo is a Nest 2020 series and does not have W2 auxiliary heat capability. 

AC Cooling Wizard