Nest seems to hang on heating cycle

[ahmedfam936]

I had installed a nest thermostat to go with my Trane system with a heat pump. I noticed heating cycle wasn't calling on the aux heat, I turned off the heat pump balance and have the aux heat lock out set to 50 deg which is default, that lets the system use the aux heat but then I noticed once it reaches a degree or two near the set temp the aux heat turns off and the heat cycle just keeps running with no heat coming. 

I thought it was an issue with my unit and had a technician come look at it and he said the unit is fine.

I'm not sure if it's an wiring issue or something within the nest that isn't allowing the heat pump and the auc heat to work parallel to heat. Since when me and the technician just wired without the nest attached the system was heating good.

[Patrick_Caezza]

@ahmedfam936 

Post a picture of the original thermostat's wiring here if you have it.

[ahmedfam936]

 thats the original 

And here is the nest

 i had the heat pump balance on and the always selected for the "use the heat pump compressor when the outdoor temperature is above". 

What happens is system runs aux heat comes on but the outdoor unit does not operate (no defrost cycle on). Vent temp gets no higher than about 82F, system runs continuously with no set temp being reached.

So not sure what it could be 

Thanks for your response

[ahmedfam936]

@Patrick_Caezza   

[AshleyB]

Hi @ahmedfam936,

Thanks for posting in the community! I understand you’re experiencing a heating issue with your Trane heat pump system. While the AUX heat activates, the Nest Thermostat terminates the call 1-2 degrees before reaching the setpoint, leaving the system running without producing heat. I appreciate the information about the settings, the troubleshooting you've already done, and the photos showing your old and new wiring. I’m happy to assist you!

To better investigate this issue, I'd like to ask for the following details:

• What type of Nest Thermostat do you have? Here’s a helpful article about how to identify your thermostat model.

• Did the issue start as soon as you installed your Nest Thermostat, or did it suddenly start later on?

• When was the last maintenance check for your HVAC system?

• Does your system have an emergency heat or auxiliary heat setting?

@Patrick_Caezza, thank you for your collaboration.

Keep me posted; I'll be waiting for your response.

Best regards,

Ashley

[ahmedfam936]

It's a 3rd generation nest learning, I had the u it serviced right after  Thanksgiving this year, I only noticed the issue since I've had the nest the last couple of years, it has the auxiliary heat.

Thanks 

[AshleyB]

Hi @ahmedfam936,

Thanks for your reply; I appreciate the information. In this case, it will be necessary to complete one last step to determine the cause of the issue.

Could you please perform a factory reset on your Nest Thermostat? Here’s a helpful article about how to restart or reset a Nest thermostat.

Please follow the steps outlined there and let me know if the issue persists.

Keep me posted; I’ll be waiting for your response.

Best regards,

Ashley

[ahmedfam936]

I'm not sure the issue is with a factory reset, the problem seems to fix itself if I set the "use the heat pump compressor when the outdoor temperature is above" to the 30s not sure why that was so. Looking online several people have this issue and that was the only fix they found

[AshleyB]

Hi @ahmedfam936,

Thanks for your reply. In this case, I would appreciate it if you could follow the steps mentioned just to follow the process. If the issue persists after this, let me know so I can look into further solutions.

Keep me posted; I’ll be waiting for your response.

Best regards,

Ashley