A/C not turning on

[Blackfam]

We installed the thermostat in the winter and the heating worked fine.  When it got warm a few days ago we tried to turn on the AC.  The thermostat is now saying no power and you can hear the furnace on, feel the fan on but no cold air.  You can hear the compressor trying to turn on but then shutting off every two minutes.  Just want to make sure it’s not a wiring problem before we get the compressor checked out to see if that’s it. Can share pictures of what the wiring looks like in the thermostat and the furnace.

[jenniffert]

Hi @Blackfam,

Thanks for posting here in the community! I'm sorry to hear that your A/C doesn't turn on as expected. Help's here!

Let me ask a few questions to better assist you:

• What is the model of your Nest thermostat?
• What type of HVAC system do you have?
• When was the last maintenance and cleaning service?
• When did you last clean the air filter?
• Do you see a power error code on your thermostat?
• Did you check if the heating is currently working as expected?
• Would you mind sharing a photo of the wiring configuration?

In the meantime, I'd suggest the following:

• Before checking the wires, turn off the power to your HVAC system at the breaker box. Then verify that the wires are securely connected to the terminals on your Nest thermostat. 
• Check if the air filter is clogged or dirty. A clean air filter is essential for proper airflow in your HVAC system. A clogged filter can limit airflow and cause the system to shut down.
• Check if your utility company has installed an energy-saving box on your HVAC system. These boxes may cut power during peak demand times, which could explain the issue.
• I would appreciate it if you could share your battery readings, VOC, and VIN by going to Settings > Technical Info > Power.

Please keep me posted.

Best regards,

Jenniffer