Need replacement base for nest 3rd gen thermostat

[reegan]

There is a problem with y1 wire. I get an error E103 on the thermostat. the technician believes the base needs to be replaced.  But I cannot find one on the website. Could some one help me with a link. Thanks. 

[Patrick_Caezza]

@reegan 

You used to be able to purchase a replacement base in the Google Nest store, but it's no longer shown. Even the Nest Pro store doesn't have it anymore.

The Nest error E103 means an over-current problem is detected on the Y1 terminal. This can be a symptom of a bad evaporator relay in the outside enclosure. The Nest thermostat is smart enough to be able to measure a change in the current draw the relay needs to operate.

[reegan]

@Patrick_Caezza  Thank you for your reply. The home warranty guy came to check and blamed it all on the base. I don't understand the electrical terms. Could you please help me with what I need to ask him to check specifically  if "change in the current draw the relay needs to operate" is happening/not. 

[Patrick_Caezza]

@reegan 

In the outdoor unit for the HVAC, there is a relay that gets energized to turn the cooling side on. That relay can start to fail, requiring more power than normal. This will cause the E103 error on the nest normally.

You need a licensed HVAC technician to check that relay's current draw and ensure it is within specifications. A lot of time, the home warranty person is just a handyman and won't know how to do it.

If this is a new home, the Nest thermostat could still be under warranty. If it is, then file a warranty claim with Nest.