Ac not turning on

[Jaswant6068]

I replaced a regular thermostat with a Nest and having a problem in which the AC will turn on, but then immediately turn off (fan in the AC starts up but then turns off, you can also hear the switch click off). The blower fan keeps on for a bit but the thermostat starts counting down to when it will turn the AC back on. Once it counts down the system goes through the same cycle: AC turns on then off with the blower running for a bit. I initially installed the nest in winter and I tested with heat and it worked. I am having issues with cool setting to turn on ac. HVAC tech bypassed thermostat at control board and it works fine. Also he bypassed at nest thermostat and ac turn on fine.

heat 

[Patrick_Caezza]

@Jaswant6068 

The blue wire is for the 2nd stage heat. It's not the C wire. You need to move it to the */OB terminal, factory default the thermostat and set it up again.

Select W/W1, Y/Y1, G/G1, R, and W2 when asked which wires you have.

I would recommend adding a C wire to ensure no future power problems.

[Jenelyn_O]

Hi there,

Thanks for reaching out. I just want to check if you managed to see the response above. Please let us know if you still have questions or concerns, as we'll be willing to assist you further. 

I appreciate your help, @Patrick_Caezza.

Best,

Jenelyn

[Jenelyn_O]

Hi Jaswant6068,

I wanted to follow up if you still need help. Please let me know if you’re still having any concerns or questions from here, as I would be happy to take a closer look and assist you further.

Thanks,

Jenelyn

[EmersonB]

Hi everyone,

@Jaswant6068, just one quick final check in here since activity has slowed down. We'll be locking the thread in the next 24 hours, but if you still need help, we would be happy to keep it open. If there's more we can do, just let us know.

Thanks for answering, Patrick_Caezza and Jenelyn.

Regards,
Emerson