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dual fuel with Y W G R O(connected to B) wires

ofreunde
Community Member

nest.com/works don't provide good solution for the wiring. 

There's no C connection in the old thermostats.

There are Y W G R wires 

and Brown color(may be orange) wire is connected to B. while O is not connected. 

 

I heard that the furnace is dual fuel system. 

What'd be the correct connection to Nest?

 

IMG_5839.jpg

5 REPLIES 5

Ryan_G
Community Specialist
Community Specialist

Hi ofreunde,

 

Thanks for reaching out and we're sorry for the delay.

 

Based on your wiring description, you possibly have a (dual fuel) heat pump. Your system is compatible with Nest Learning Thermostat. 

 

We could use the O or B wire as a common wire when you get it connected to the Nest Thermostat.

 

Let us know how it goes when you try it to connect with Nest Learning Thermostat.

 

Best regards,

Ryan

Ryan_G
Community Specialist
Community Specialist

Hey ofreunde,

 

I just wanted to follow up and see if you are still in need of help? Please let me know, as I would be happy to answer any questions you may have.

 

Best regards,

Ryan

ofreunde
Community Member

Thanks for the info. It is dual fuel system. Actually the heater was broken and I needed to call technician, and let him install the nest. After all work done I found that he didn’t connect B to anywhere. Only 4 wires are connected and it’s working. But as far as I know, nest will not get charged if heater or cooler is not working. 
would it be safe to connect the brown wire to connect to C?

Ryan_G
Community Specialist
Community Specialist

Hey ofreunde,

 

Thanks for the update.

 

You're right that the Nest Thermostat get's a little power from your heater or cooler to keep it charged. 

 

You could also try to connect the brown wire to the C terminal to be used as a common wire as it is only for a stable power purpose.

 

Let me know how it goes by replying to this thread.

 

Best regards,

Ryan

Ryan_G
Community Specialist
Community Specialist

Hey folks,

 

Thanks for visiting the Google Nest Community. 

 

Since this thread hasn't had activity in a while, we're going to close it to keep content fresh.

If you have additional questions, feel free to submit another post and provide as many details as possible so that others can lend a hand. 

 

Hope this helps!

 

Kind regards,

Ryan