Thermostat not compatible

[Steveningles]

app says not compatible.  Any thoughts here?

C

B

RH

W

[CoolingWizard]

@Steveningles , the incompatibility comes from the B being used and no Y terminal and no G terminal.  Your current  thermostat is either controlling a heating system only such as baseboard heating. Can describe for me your HVAC system? Heating and cooling if you have both. 

AC Cooling Wizard

[Steveningles]

Thanks @CoolingWizard    I only have heat that is radiant heating. Here’s a pic

 

[CoolingWizard]

@Steveningles ,

If you notice your current thermostat states for 120/240 volts only. You need to verify your system control power using a Volt Ohm multimeter.  

AC Cooling Wizard

[Steveningles]

Thanks @CoolingWizard   The thermostat states it to NOT connect at those levels.   This could be 24 volts as the wires are small. Are one of these wires interchangeable with a more satisfactory choice for nest?   Example, can I select “R” instead of “RH” and that will suffice?   I don’t think  it’s a voltage issue but I could be wrong.  It’s a newer house with radiant heat only    Thanks again. 

[CoolingWizard]

Can go to the other end of the thermostat cable het pictures of where the wires attached?

AC Cooling Wizard