Best Thermostat not cooling

[Bliang]

Nest is set to 72 deg, and it shows the ambient is 77, however, the AC wouldn’t turn on and will not reach 77. Once I turn it down to 71 deg, the AC turns on, but after a short while it shut off again, and it is still at 77 deg.

[Rezahendricks]

I am also facing same issues

[CoolingWizard]

@Bliang and @Rezahendricks ,

are you saying that your Nest display turns blue, indicating it’s in cooling mode, and then after a few minutes it turns black again saying that’s no longer cooling. Or are you saying that it’s remains blue but your outdoor unit turns off?

AC Cooling Wizard

[Bliang]

Yes. It will be blue and indicates it’s cooling and before it reaches the desired temperature it shut off AC and turns grey

[SoriaD_]

Hello @Bliang 

Thank you for reaching out to our Nest Community about your Nest thermostat's cooling option. I apologize for all the inconvenience. I'm here to help you with that. 

I would appreciate it if you could share with me the following details:

• What type of Nest thermostat do you have? 
• What type of system do you have? (Heat Pump or conventional type)
• Do you see a message code on your thermostat?
• Have you set up a temperature schedule for your thermostat?

Also, all the troubleshooting steps you tried before could be very useful to determining the solution for this case.

Feel free to keep us posting; I'm happy to help you out.

Best regards,
Douglas.

[RPierce]

I am having same issue. Mine is blue briefly but will turn off long before my temperature even approaches target temp. I set up two schedules one to start at 4 PM (an hour before we came home) to begin cooling to 75. At 6 PM we are still at 81. After it turns black, it will have a count down timer again, after which it hits ) and comes back on for a short while.

[CoolingWizard]

@RPierce ,

when you see the countdown timer, that’s typically when the battery does not have sufficient charge to operate the system. Verify that you’re getting proper power on the R and the sea wire to your thermostat you should be receiving between 24 and 29 V of AC power. 

AC Cooling Wizard