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Nest Thermostat Doesn't Turn-Off with Navien NCB-190

aa54
Community Member

I recently have my heating and hot water systems replaced with Navien NCB-190/060H(NG) combo system. My old Nest thermostats, used to work very well with the old system, don't turn off with the Navien. They heat up but refuse to turn off, I have to unplug the Nest from the wall base to turn off the heat. Any suggestions/recommendations appreciated. Below is a picture of the Nest connections.20221002_102130.jpg

17 REPLIES 17

Houptee
Silver Product Expert
Silver Product Expert

Post pics of the connections at the combo unit. Where are they wires connected?


Houptee -- NJ Master HVAC Licensed Contractor

aa54
Community Member

Thanks. Here are a few pics.
Please note that R, W, C(green) on the thermostat end (top left) are swapped to Blue, Yellow, and Black in the junction box (top right). In the combo unit (bottom picture) these three connections are visible towards the right side.Image2022-10-18.png

Houptee
Silver Product Expert
Silver Product Expert

Looks like correct wiring at both ends.

Did you tell Nest it was a radiator system, and not a hot air system?

All the Nest does in this system is conncet Red to White like a switch, When it wants heat it sends 24V from the red wire to the white wire.

 


Houptee -- NJ Master HVAC Licensed Contractor

aa54
Community Member

Yes, I did instruct Nest that that it is a radiator system.

I recently replaced my old heating system with Navien combo. The two Nest thermostats in my unit have been working fine with the old heating system and ran into problems from day one when the Navien system is installed. Looks like I have to throw away the two Nest thermostats and get a different brand (More than $350 down the drain). I feel it is a shame on Nest not coming up with a solution for an upcoming brand of heating system,

Houptee
Silver Product Expert
Silver Product Expert

I only see one set of thermostat wires connected to the Navien. You said there are 2 in this system. Do you know where the 2nd thermostat wires connect?

The Navien has 2 sets of screw terminals for 2 zones but you are only using one set.

If you look in the manual for the Navien it will show how to wire 2 thermostats to the terminal strip screws.

This might be why it is acting erratic if they wired the 2 stats in series.


Houptee -- NJ Master HVAC Licensed Contractor

aa54
Community Member

You caught it, clever eyes....the upstairs Nest is now replaced with a traditional thermostat until we can make downstairs work

Houptee
Silver Product Expert
Silver Product Expert

OK just make sure each tstat goes directly to the Navien to the correct screws for each zone.

Nest should work in this system it is very basic setup not sure why you are having problems.


Houptee -- NJ Master HVAC Licensed Contractor

aa54
Community Member

Thanks for all your expert feedback. I will pass this info to the contractor (he is on vacation right now) and hopefully he will be able to work out the solution. Will post an update.

EdwardT
Community Specialist
Community Specialist

Hi folks,

 

@Houptee, thanks for the help!

 

@aa54, how's it going with your Nest Thermostat? Let us know if you have other questions and we'd be glad to help.

 

Thanks,

Edward

EdwardT
Community Specialist
Community Specialist

Hi aa54,

 

I wanted to follow up and see if you are still in need of any help. Please let me know if you are still having any trouble from here, as I would be happy to take a closer look and assist you further.

 

Thanks,

Edward

EdwardT
Community Specialist
Community Specialist

Hi folks,

 

@Houptee, thanks for the help!

 

@aa54, how't it going with your Nest Thermostat? Still need our help?

 

Thanks,

Edward

aa54
Community Member

Thanks for the follow up. Yes, the two Nest are still not working with the Navien system.
I have almost given up and looking into getting old fashioned thermostats installed. I even contacted Navien and they said to have the installer call them when on site. But he was not willing as he says he is not an expert in electicals. Navien says they only want to talk to the licensed installer.
Altogether its disappointing that the two Nest thermostats I purchased last year and used on an older system are now being set aside.

EdwardT
Community Specialist
Community Specialist

Hi aa54,

 

Thanks for the response. We'd like to know more about this. Please fill out this form so we could investigate further.

 

Thanks,

Edward

EdwardT
Community Specialist
Community Specialist

Hi aa54,

 

I'm checking back in. Were you able to fill out the form? Let us know if you have questions and we'd be glad to assist you.

 

Thanks,

Edward

Jhonleanmel
Community Specialist
Community Specialist

Hi folks, 
 

@EdwardT, thanks for the help.
@aa54, I wanted to follow up and see if you are still in need of any help. If so, please fill out the form so we can help you further.

Best,
Mel

aa54
Community Member

Sorry for the late response. Just submitted the form. Thanks,

Jhonleanmel
Community Specialist
Community Specialist

Hey there, 

We got your form — thanks for filling it out. Keep your lines open as our team will reach out to you via email anytime soon. 

Also, please continue the conversation there as this thread will be locked after 24 hours.

Cheers, 
Mel