Nest Snow - wiring compatibility App vs Wire Checker

[mdobbin99]

Hello and thanks for the help.

After checking compatibility and even confirming with support - when I try to install new Nest Snow the app stops me and says that my system is not compatible.

Below is picture of current (programmable WiFi Sensi) wiring and labels. 5 wires. System works great.

• Any guidance if I can install with Nest Snow and if so which wires go to which. 

(system is a oil powered boiler system that leverages forced air for heat and AC unit (outside) using same forced air for cooling.)

current wires: RC - RH - Y - G - W/E (vs the labels Nest Snow has of: Y - C - W - G - R - OB)

THANK YOU!

[EdwardT]

Hi mdobbin99,

Thanks for reaching out. I'm sorry to hear that you're having an issue with your Nest Thermostat and I have a few questions:

• What type of Nest Thermostat do you have?
• Are the RC and RC 2 separate wires or is there a jumper?
• How did you wire your Nest Thermostat?

Looking forward to your response.

Thanks,

Edward

[mdobbin99]

Thanks Edward - I have Nest Snow. 
there is no jumper for the RC and RH wires.  Was told that is the issue and will not work. True?

I did not wire the nest and that is why I asked question.  Do not know how to wire it. 

[graussofj]

I have the same problem.  The compatibility app tells me that the Nest snow may work with my system.  I have separate wires for Rh and Rc, but there is only an R terminal on the nest.  Apparently I have a dual transformer system, one for heating which is gas hot water, and one for cooling separate system in attic.  Question is, can you connect both Rh and Rc wires to the R terminal, and will that work? There is no information on how the thermostat works, i.e., which terminals connect to call for heat and for A/C.  Or maybe this thermostat will not support my set-up?

[mdobbin99]

I spent time on with a support person.  She said after 30 minutes and understanding the rc and rh issue that only would work with the top of the line and most expensive Nest Learning thermostat.  

oh well. 

[graussofj]

Hi Edward,

Thanks for your support on this.  I actually have 5 zones on my hot water baseboard system and two separate A/C units.  Only two of the zone Thermostats control separate A/C zones so there are actually three different 24V transformers that are in play here.  I suppose if I were to supply all three systems from a common 24V transformer, I could make this work.  I don't know if I want to do this, but I would like to know if it was a possible solution.

[EdwardT]

Hi folks,

Thanks for your response. Based on your description, you have a dual transformer system and this is not compatible with the Google Nest Thermostat as it only has a terminal for the power. I would suggest looking into the Nest Learning Thermostat as it has 2 R terminals for your system.

Thanks,

Edward

[EdwardT]

Hi folks,

It's me again. I wanted to check back in to see if you have other questions and concerns. Feel free to let me know if you do. 

Thanks,

Edward

[Jhonleanmel]

Hi everyone,

Just one quick final check in here since activity has slowed down. We'll be locking the thread in the next 24 hours, but if you still need help, I would be happy to keep it open. If there's more we can do, just let me know.

Thanks,
Mel