heat oil - water boiler question

[mataushas]

I used the compatibility checker and I'm getting the "may work" answer for this thermostat.

I currently have a boiler (hot water) heat only thermostat & system. The only wires are R and W. You can see these R & W wires on the left side of my boiler controller. Technically, I only have 1 zone so zone 1&2 have a jumper. So only 1 R and 1 W wire is going to the only thermostat in my living space. C wire is unused today.

I believe my boiler uses "dry" T-T connection but I haven't confirmed this myself. This is just based on my search. Given that, I'm reading that I may need a relay to make any thermostat including Nest work with my system.

I don't really want to buy this thermostat and not have it work and have to return it. I'd rather get the answers here and have a plan.

Do you think I need a relay and a separate transformer?

https://imgur.com/a/4PIy7vs

[RenzJ]

Hi mataushas,

Thanks for visiting the Google Nest Community. I'd be happy to take a look at this for you. A two-wire system can work with the Nest Thermostat, but there are cases where a common wire is needed for it to work properly. The common wire can provide constant power. You can have a common wire installed in your system by a technician or a Pro.

Another thing that you can consider is our Nest Power connector. It’s a small device that will act like a common wire in your system.

To learn more about it, you can go to this link Nest Power Connector.

Let us know if that helps.

Best,

Renz