cancel
Showing results for 
Search instead for 
Did you mean: 

Nest w connection has blue wire. Is that a concern? There is nothing plugged into the W

Jmatt
Community Member

7F9E66F7-E8B3-4230-9FF3-5CECC3AF35D3.jpeg

The W is connected to a blue wire and the C does not have anything connected to it.  There is a white wire however it is not connected to anything.  

15 REPLIES 15

Jay_Utah
Community Member

I would check your furnace out and see exactly what the blue wire is connected too and match that to your new one. 

Houptee
Silver Product Expert
Silver Product Expert

What kind of system do you have?

Is it a Heat Pump? Or a Nat gas furnace with AC?

You need to use one of the extra wires as a C wire and connect it to the furnace C terminal screw.


Houptee -- NJ Master HVAC Licensed Contractor

Jmatt
Community Member

Thanks.  i don’t have a heat pump.  Natural gas furnace 

Houptee
Silver Product Expert
Silver Product Expert

I suggest you go to the furnace and remove the cover.

Locate the terminal screws where the thermostat wires connect.

I would fix the strange wire colors they used and put the White wire on furnace W

Put the Blue wire on furnace C common (or if it is a Trane they call it B)

Then go back to the Nest and put

Red in RC

White in W1

Blue in C

G in G

Y in Y


Houptee -- NJ Master HVAC Licensed Contractor

Jmatt
Community Member

Thanks Houptee.  I checked the white wire just hanging there and it has 12 mV power from the multimeter.  I’m wondering if it was installed without the white wire since the thermostat runs off battery- not sure why.  I’m still looking for the terminal near the furnace to confirm the wiring

Jmatt
Community Member

Ok..good news.  I installed the nest using the following wires and it is working and responding.  
W - Blue

Rc - red 

G - green 

Y - yellow 

W - was left not connected.  
should there be any concern with that setup?

Houptee
Silver Product Expert
Silver Product Expert

If it is getting good power when you do the power test and you get good readings it should be ok.

But connecting a C wire is always the best thing to do on these smart thermostats.

You just remove the front cover on the furnace and you will see the wires and screws in a row R Y G C W etc etc.

If you want to make it standardized to the normal color code you can move white to W and blue to C.

This video shows you how to test if you need to attach the C wire but i would do it anyway even if you have decent voltage.

https://youtu.be/GHkfnRp6Tj8

 


Houptee -- NJ Master HVAC Licensed Contractor

Jay_Utah
Community Member

I figured that was the case. As king as you remember for another time. You could put a small label on the wires coming out of the wall

Something came out wrong on my last post. Just saying label the wires. Blue being where White should go. I believe white is for heat.

EdwardT
Community Specialist
Community Specialist

Hi folks,

 

@Houptee and Jay_Utah, thanks for the help!

 

@Jmatt, I'm glad to hear that you were able to install your Nest Thermostat. Please observe it for now and let us know if anything comes up.

 

Thanks,

Edward

aatienza
Community Specialist
Community Specialist

Hey there,

 

I just wanted to follow up to see if you still need our help. Please let us know as we would be happy to answer any questions you may have. 
 

Thanks,

Archie

aatienza
Community Specialist
Community Specialist

Hello there,

 

Just checking in to make sure that you've seen our responses. Please let me know if you have other questions or concerns as I will be locking this in 24 hours if I won't hear back from you again. Feel free to start a new thread and we'll be happy to help.
 

Thanks,

Archie

Jay_Utah
Community Member

It does work : ) thanks for the help

I do need a backing plate do you know where I can get that? 

aatienza
Community Specialist
Community Specialist

Hey Jay_Utah,

 

That's good to hear! You can fill out this form and let us know once you're done.

 

Thanks,

Archie

aatienza
Community Specialist
Community Specialist

Hey Jay_Utah,

 

We got your form — thanks for filling it out. Our team will reach out to you via email to further assist you. Also, please be advised that this thread will be locked after 24 hours.
 

Thanks,
Archie