Nest Power Connector compatibility

[dreed]

I installed a Nest thermostat to replace a simple 2-wire heat only thermostat.  The original thermostat wiring had only the red and white wires.  I used the Nest Power Connector to provide the C wire function and everything worked great.

My question is, what if I needed to put the original Honeywell “dumb” thermostat back in for whatever reason, without removing the Nest Power Connector.  Would the presence of the Nest Power Connector cause problems with the original thermostat?  It is a Honeywell TH1100DV1000.  The Nest Power Connector was needed to make the Nest thermostat happy.  Would the Nest Power Connector make the original thermostat unhappy?  Obviously the Nest Power Connector is not needed by the original thermostat.  But would the Nest Power Connector and/or original thermostat be damaged or not work if they are used together?

[MelbaDT]

Hey dreed, 

Thanks for reaching out and sorry for the delay. 

Our Nest Power Connector should be least of your worries when you should want to install back your original thermostat. It will just act as a C wire and should not cause damage to your system or your thermostat. Also, should you decide not to make use of it,  you could just tape the end, push it against the wall and not connect it to the C terminal of that thermostat. 

Best, 

Melba

[dreed]

Thank you for the response.  Just to clarify, though, at the end you said you could just not connect it to the C terminal of the original THERMOSTAT.  Don’t you mean the C terminal at the FURNACE EQUIPMENT end?  Remember that the original thermostat had just 2 wires going to it (R and W), so there was no C terminal at the thermostat.  Perhaps you meant to say the C terminal (at the furnace equipment) FOR the thermostat?   And if I were to go to the furnace equipment end to do this, I would simply remove the Nest Power Connector entirely and connect the wiring the way it was originally.  I was trying to avoid going back to the furnace equipment end at all.  From the first part of your answer, you are saying that it is OK to leave the Nest Power Connector just as it was for the Nest when I put the original thermostat back in.

[Ryan_G]

Hey everyone,

I'd like to jump in here and check if you've seen Melba's response. Let us know if you need more help by replying to this thread.

Thank you for your help, Melba.

Regards,
Ryan 
 

[Ryan_G]

Hey there,

Thanks for being here in the Google Nest Community. 

I'd like to bump in here and make sure that you’ve seen our response.
Please let us know if you have any other questions or concerns as I will be locking this thread in 24 hours.

Have a great day.

Best regards,
Ryan
 

[dreed]

Thanks for following up.  Before you lock this thread, I did just ask Melba to clarify something.

[Ryan_G]

Hi dreed,

Thanks for the reply.

In addition to what Melba has mentioned, since your original thermostat had 2 wires (for power and for heating), the C wire is not necessary to be connected. The only time you'd use it is when you switch to the Nest Thermostat where it needs to have a stable power supply. 

Regards,

Ryan

[dreed]

Like Melba, you confuse me when you start talking about a C wire and not needing to be connected.  Yes, the original 2 wire thermostat did not have or need a C wire.  But remember that I’m asking about leaving that Nest Power Connector as is if I were to take the Nest thermostat out and put the original thermostat back in.  It sounds like that is OK to do, without touching any of the 5 wires at the Nest Power connector.  That’s OK to do, right?

  I think what you and Melba are also telling me is that if I wanted to, I could disconnect the C wire between the Nest Power Connector and the C/com terminal at the furnace control board.  But why would/should I do that if I don’t have to?!  You aren’t telling me I have to, right?   If I were to go to the furnace control board to disconnect the C wire from the Nest Power Connector there, I would go all the way and remove the Nest Power Connector completely and put the R and W wires back directly to the furnace control board as before.  I want to make sure that the Nest Power Connector can support either  thermostat without having to change anything at the furnace end.

[Ryan_G · Accepted solution]

Hi dreed,

Thanks for your reply and we're sorry for the delay.

The Nest Power Connector is a tool that provides additional ways to supply power to your Nest Thermostat. The Nest Power Connector can support either thermostat without having to change anything at the furnace end.

Regards,

Ryan

[Ryan_G]

Hey dreed,

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

Best regards,
Ryan
 

[dreed]

All set, thanks for the help!

dreed

[MelbaDT]

Hey there, 

Glad to hear that and thanks for getting back to us. We'll then go ahead and lock this thread after 24 hours. If you have any new issues, updates or just a discussion topic, feel free to start a new thread in the Community.
 

Best, 

Melba

[dreed]

Please do not lock this thread until you and/or Melba clarify your replies per my latest post.  Thank you in advance.

[dreed]

Hello, Ryan G,

Not sure how this post got marked as the “solution” when it doesn’t offer any technical advice or follow up.  Melba has gone quiet and neither of you have followed up on my request for clarification.  So I’ll ask it again…. Is it ok to leave the Nest Power Connector in place with the original 2 wire (R and W) non-Nest thermostat without disconnecting ANY of the 5 wires at the Nest Power Connector or furnace terminal board?  Yes or No?  Melba said leaving the Nest Power Connector in should be the least of my worries.  What should I be worried most about?   The Nest Power Connector was designed to work with the Nest thermostat.  Are you sure it can work with my Honeywell thermostat that does not need it?  Have you actually tried this or know of others who have tried this?

If Melba is the technical expert on this, would you please give her a nudge for me?

Thank you,

dreed