Furnace turns off and on repeatedly after installing new learning nest thermostat

[Elly2]

Hi there,

I was using Alarm.com smart thermostat and just got a new learning thermostat as an upgrade.

Current wires are W,Y, Rh, and G.

After I installed the new thermostat, my furnace keeps turning on and off non stop. There was no error code indicated in the app. I worries it would damage my furnace. Therefore, I changed it back to the old thermostat and there is no issue. 

Does anyone knows the problems here? Thank you

[q_t_]

I am having the same issue. I turned the thermostat off, but it’s still coming on - on it’s on. 

[Jenelyn_O]

Hi folks,

@Elly2, thanks for reaching out. I'm sorry for the trouble this has caused you. I'd like to take a closer look at it. Could you please provide your Nest Learning Thermostat's power readout? Also, check your system's control board, and see if you can find any extra wires that we can use as your C wire. 

Check out this guide to check your thermostat's power readings:

1. Go to your thermostat Quick View menu.
2. Go to Settings.
3. Look for Technical Info.
4. Select Power.

@q_t_, a few questions: what type of Nest Thermostat do you have? In what country are you located? Do you have a C wire? What system (heating or cooling) keeps running even if your thermostat is off? Do you see any messages or codes on your thermostat or in the app? Please check your thermostat's power readings.

Best,

Jenelyn

[Elly2]

Hi Jenelyn_O,

I do not have c wire but just purchased a nest power connector and it seems working fine now. 

It's a little annoying as I bought the learning thermostat to avoid dealing with the c wire issue but it still happened.

[Jenelyn_O]

Hi there Elly2,

Thanks for letting us know that it's now working fine. We apologize for the inconvenience you experienced. Please feel free to create a new thread if you have any questions or concerns, as we'll be willing to assist you from there. 

Cheers,

Jenelyn