Thermostat turns off & then back on within 1 second

[jarvisvw]

Gen 3 Nest Learning Stat is running fine after about a week.

In cooling mode, condenser on, indoor fan on,

It randomly stops, then restarts within 1 second. This makes a HUGE noise & I can hear the motors and the wiring vibrate in the house.

About twice a day,  but completely random.

System info:

1 Stage Cooling

1 Stage Heat

2 transformer setup (RH and RC)

 

[MplsCustomer]

@jarvisvw 

Yipes! We don't have a Nest thermostat, but if our conventional programmable thermostat were doing this, I would be calling our heating and cooling support number. You may have to contact Google Nest Support to either tell you how to avoid this behavior or provide a replacement.

https://support.google.com/googlenest/gethelp

[Midknight]

I would suspect the contactor in your AC unit is faulty or your start/run capacitor is defective in your AC unit.

[underdog2904]

I had a new HVAC installed July 5th and I had this exact same thing happen to me.  Compressor on, outside fan running, inside fan running, house is cooling. Then all of a sudden I hear a extra loud startup sound from the compressor area. But it was already running so why did it do that? I did some research and read that I really needed the C wire (blue) connected to my Nest 2nd Gen. Otherwise strange things may or may not happen. I found out that I had a blue wire all along in my thermostat cable in the wall but it was cut short long ago before I bought the house. Anyway the thermostat cable had some slack in the wall so I pulled it out enough to get the blue wire connected into my Nest. I have not heard that loud sound in a few weeks. But my AC is not running as much as it was during the extra hot summer because temps are getting slightly cooler around here. But I have read online that not having the blue wire on the Nest is really causing issues for some people. I have since bought the Nest 3rd gen about 1 week ago. So far so good. The HVAC guys that did the installation did not seem to like Nest thermostats. They said Nest causes issues sometimes. But I've also read on line that some HVAC guys like them. So I don't know. We'll see I guess.

[EdwardT]

Hi folks,

@MplsCustomer and Midknight, thanks for the help!

@underdog2904, thanks for sharing. Nest thermostats are designed to use very little power, and in many cases they can use your system’s heating and cooling wires to get enough consistent power. But sometimes, you may need to connect a common wire (C wire) or power accessory, like the Nest Power Connector, to make your system compatible. Please observe it for now and let us know if anything comes up.

@jarvisvw, thanks for reaching out. I'm sorry to hear that you're having an issue with your Nest Thermostat. I'd love to know more about this and I have a few questions:

• What type of Nest Thermostat do you have?
• How is your Nest Thermostat wired?
• What is the power reading of your Nest Thermostat? You could find this info by going to Settings > Technical Info > Power.

Looking forward to your response.

Thanks,

Edward

[EdwardT]

Hey folks,

It's me again. I wanted to check back in to see if you have other questions and concerns. Feel free to let me know if you do. 

Thanks,

Edward

[EdwardT]

Hey folks,

I'm just checking in to make sure that you've seen our response. Please let us know if you have any other questions or concerns as I will be locking this in 24 hours.

Thanks,

Edward