Nest 3rd gen says cooling only even though I only have a heat only hydronic system.

[dcorcoran]

@Patrick_Caezza you might know about this

I’m trying to set up this thermostat for the first time. I have a heat only single zone hydronic system run by gas boiler. My old Hunter Brand thermostat had only two wires plus a jumper. White wire was to a Y1 terminal and a red wire to the Rh with a jumper to the RC.  I hooked up those wires per the nest instructions but now my thermostat only shows cooling but it’s running the heat all the time. Got my house up to 76° before I shut the thing off. Looking at the equipment detected it’s telling me that the white /Y1 terminal is cooling so that seems to be incorrect. Any idea what terminal would control the heat? 

[aguilarmateo · Accepted solution]

Hi dcorcoran,

Sorry to hear the situation that you are experiencing installing the Nest Thermostat, but help is here! You can follow the next troubleshooting steps in order to install the Nest thermostat correctly: 

• White wire (W1): This wire powers the heating system and must be connected to the W1 terminal on your Nest thermostat.
• Red wire (RH): This wire supplies power to your thermostat and must be connected to the RH terminal.

Nest thermostats typically don't require jumper wires.

For a more detailed guide, you can check out this video: How to install a Nest thermostat, 

Let me know if you have any questions. 

Best regards,

Chris

[Patrick_Caezza]

@dcorcoran 

That's interesting but in theory, it should be connected to the W1 terminal like @aguilarmateo  said.