Hi Christopher28
Google Nest thermostats are designed to work in most cases without a common wire. Instead of using a common wire to keep your thermostat charged, your Nest thermostat can use the Y1 (air conditioner) wire to power itself.
If your air conditioner stops sending power to your thermostat, your thermostat can let you know with one of these errors. There are a number of reasons why your air conditioner might stop sending power to your thermostat. Below we list some possible reasons, but it’s important to contact a professional to diagnose your system and determine what the root cause of the error is.
- One possible reason is that your system needs maintenance. If your system breaks down, it will likely stop sending power to your thermostat. An HVAC professional can help determine if your system needs repair.
- Another possible reason is that you live in an area that experiences very cold temperatures in winter. Your air conditioner may come equipped with a safety device that will stop it from turning on in extremely cold weather to prevent damage. These safety devices, sometimes called low pressure switches (LPS) or safety cut-out switches, can sometimes prevent your air conditioner from providing your Nest thermostat with power in extremely low temperature conditions.
If you see one of these errors (E10, E30, E66, E80, E116, E160, E196, E296, and M13), you can use the quick fix below to help get the heat back on. Then, when it's convenient, call an HVAC professional such as a local pro to come take a look at your system and install a common wire or the Nest Power Connector.
Check this guide for more details.
Best,
Mel
