06-04-2022 05:35 PM
I am trying to install a nest thermostat.
I believe my system is compatible. I do have two wires connected by wire nuts, but they are not thick or stranded.
This is a simple newer furnace with no ac. Should be easy - only three wires: R, G, W. But I have an e74 error saying there is no power to the Rh wire. I have confirmed with a multimeter that there is 25 v difference between the R and G wires.
I have tried charging the thermostat via USB and it has restarted itself a couple times.
06-05-2022 07:58 PM
Post a picture of the original thermostat's wiring.
06-06-2022 08:53 AM
06-06-2022 08:55 AM
Existing thermostat photo above. I should mention that the heat does work with the existing thermostat.
06-06-2022 03:10 PM
Interesting wiring.
It looks like the blue and white wires are wire-nutted together for some reason.
Can you post a picture of the terminal block on the control board in the furnace/air handler?
06-07-2022 08:55 AM
Thank you for taking and interest and helping. There are three pictures below. First, the one I think is the terminal block you are asking for. the other two show that following the thermostat wires is not as strait forward as I might hope.
06-08-2022 12:27 AM
Is there something like this installed at the thermostat?
Does you system have cooling as well as heating? or just heat?
06-08-2022 08:14 AM
I don;'t see anything like that. it's heat only.
07-28-2022 09:50 AM
Hi jackgoss,
Sorry for the delay in a response here, but I wanted to check in and see if you were able to get this sorted out or to see if you were still working on things. If you're still having issues, let me know so I can help you out from where you've left off.
Thanks,
Jeff
07-29-2022 07:38 AM
I have not made any progress. I would welcome any help. I looked up the add-a-wire thing and found instructions for installing it but haven't understood how to adapt to it being there.
07-29-2022 11:49 PM
Hey jackgross,
I understand where you're coming from. Are you pertaining to the Nest Power Connector? If yes and you've already installed it, are you getting a message or a code on your thermostat display? I also suggest that you try the troubleshooting guide here: https://bit.ly/3ujTiLa
Keep us posted.
Best,
Melba
08-04-2022 06:01 AM
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
08-04-2022 09:21 AM
I'm afraid I don't understand Melba's response.
08-04-2022 09:23 AM
After reading some more about the Add a Wire I went looking for something like this. I think there is something like this attached the to the blue wire shoved into the wall where the wires come out, but I was afraid to pull on it too hard to verify.
08-08-2022 11:42 PM
Hey jackgoss,
Sorry for the confusion. You've mentioned that you've added a wire after some researches so I wanted to ask if that wire was the Nest Power Connector. Also, if you're afraid to pull out the wire to verify where it is connected to, you might want to ask the assistance of an HVAC technician or a local pro.
Best,
Melba
08-09-2022 08:51 AM
I didn't add the wire, I found it like this, presumably from the last thermostat installation. I will probably have to hire someone for this.
08-10-2022 07:28 PM
Hey there,
Got it and I understand. Hiring a professional is the best option as they will need to check on that spare wire if it can be used as a Common Wire. Please contact a local pro.
Best,
Melba
08-15-2022 07:49 PM
Hey there,
Checking back in should you still have further questions here. Let me know by replying to this thread.
Best,
Melba
08-16-2022 07:54 PM
Hi,
We haven't heard from you in a while so we'll be locking this thread if there is no update within the day. If you have any new issues, updates or just a discussion topic, feel free to start a new thread in the Community.
Best,
Melba
08-16-2022 08:30 PM
I have not had time to come back to this project. I will try again later when I have some free time.
08-16-2022 08:39 PM
Hey there,
Gotcha — thanks for getting back to us. I'll keep the thread open for a few more days while waiting for your update.
Cheers,
Melba
08-23-2022 03:14 AM
Hey there,
It' me again — how's it going now? Have you had the chance to have your system checked by a professional already?
Best,
Melba
08-24-2022 05:12 AM
Hi,
We haven't heard from you in a while so we'll be locking this thread if there is no update within the day. If you have any new issues, updates or just a discussion topic, feel free to start a new thread in the Community.
Best,
Melba