Wire configuration for nest 4th generation thermostat

[Pliguori]

Hello, I have a very basic 3 wire system with which I do not have any zone valves. I’m Hank g trouble setting up nest power connect to my system. There is no “c” wire from the boiler, but I do have spare wires running to the thermostat already.  I’m looking for assistance w/ the boiler configuration please? I have a fan in a can connected with no issues, but nothing wants to work.  The only hookup that I had, wouldn’t allow the boiler to turn over. This is what I have.

[catheryn]

Hello @Pliguori, 

Thanks for bringing your concern to our attention and posting it in the community. 

I understand you have some questions regarding an initial setup of your Nest power connect and the boiler configuration. No worries, I'm here to help. 

Before I can provide specific advice, I need to confirm a few details:

• Is your Nest thermostat already installed?
• How many thermostats do you have? 
• How many HVAC systems do you have?

In the meantime you may find this article useful: How to install the Nest Power connector. 

Please let me know if you need further assistance. We're here to help.

Thank you, 

Catheryn