Turn the power to your system back on and test that its working. Make sure that the wires are placed in the right connectors.

Nest E Y1 Cable Cutting Power To Thermostat Home
Nest thermostat not receiving power. Look for bent or distorted pin connections on the back plate. Your nest thermostat has detected a g 2 fan wire in the y 2 connector and an emergency heat wire in the connector. This lets you see if your nest thermostat e is locked or unlocked. G 2 wire detected. Nest thermostats that were updated at the end of 2015 or beginning of 2016 to software version 513 or later may have some issues including becoming unresponsive not efficiently charging the battery or shutting down completely. Check your homes power supply.
The error that youre getting on your y1 wire means that the thermostat is not receiving power from your system. Some heat pump installations may have the auxiliary heat connection labelled as x w1 or w2 on the thermostat. The nest will work without a c wire so once the nests are working without the c wire turn on each nest and see which furnace turns on and notate which nest controls which furnace and then you can connect the corresponding c wire on both ends. Make sure that you still have 24vac between r and c on the back plate and that the r and c wires are solidly attached when you pull on them. Now if the circuit thats powering your thermostat trips then youll have a loss of power. When x w1 or w2 is an aux wire.
The nest thermostat does not support multiple stages of heat and multiple fan speeds at the same time. The nest thermostat e will list a device id thats unique to your display. You should verify that the x wire on the old thermostat is not a common wire. Contact a local pro if you need more help. Nest suggests recharging and restarting your thermostat to resolve the glitch and get it up and going again. First inspect your homes circuit breaker.
If your thermostat isnt receiving enough power to charge the battery and it falls below 36v your thermostat will turn off wi fi delay software updates and disable the screen to preserve. The reason is because your homes electrical system is what runs the thermostat. If you know your thermostat is turned on then its time to investigate a little further. Hello we can continue from here. If there is a common wire installed the nest thermostat will not power share. Uninstall your nest thermostat and reinstall your old thermostat.
Phil mechanical engineer replied 2 years ago. You can try to remove the y1 wire on the base of the thermostat then reconnect.