Thermostat wiring

[Mtee]

I would like to install Nest Learning Thermostats 3rd gen. I have 3 zone baseboard heating from a boiler. The heat only thermostats currently have an Rh and W connection. The Rh and Rc are jumpered. The thermostat that controls heat AND AC has the following wires: Rh, W, Y, G and a blue wire to the Rc. I have no common wires. Please tell me how to connect my new Nests to both configurations (heat only and heat + AC). 

[Jenelyn_O]

Hi Mtee,

Thanks for reaching out. I'd like to help. For your first thermostat, you just have to connect the wire responsible for your heating in the W1 terminal of Nest Learning Thermostat. Since the Nest Thermostats don't use jumper wires, you just have to connect your power wire to the RH terminal.

It looks like your second thermostat has a dual transformer. You can follow the wiring below:

• W1 - Heating
• Y1 - Cooling
• G - Fan
• RH - Power (Red)
• RC - Power (Blue)

Best,

Jenelyn