Unlabeled thermostat wires

[zb36]

Hi all! I am trying to install my nest thermostat for heating only and have a baseboard heater boiler system in my unit/building. I have 4 wires coming out of my wall: one red labeled W1, one red labeled R, and two unlabeled white wires that have been twisted together. Does anyone know what the white wires could be and why they’d be tied together? I’m trying to see if my nest is compatible. 

[AndersC]

Hi @zb36,

Thank you for posting in the community. I understand you need to know if your Nest Thermostat is compatible with your heater boiler system. I'll be glad to assist you with this. 

Have you visited the online Compatibility Checker to confirm compatibility between your Nest Thermostat and your system?

I would also appreciate it if you provided the information requested below:

• What type of Nest thermostat do you have?
• What is the make and model of your HVAC system?

Let me know if you have more questions.

Regards, 

Anders