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Is my wiring compatible with a nest thermostat?

aeisenberg
Community Member

I have 4 wires going into my current thermostat: R, i+, i-, C. Is this compatible with a nest?

There is also a sticky note that says:

"Caution: 24 VAC Low Voltage Wiring only"

Is it possible to use this for a nest and what is the wiring configuration? Thanks.

1 Recommended Answer

aeisenberg
Community Member

Yes. After a lot of research, and a consultation with an HVAC expert, I was able to rewire to install the nest.

The i+, i- wires are specific to lennox furnaces and iComfort thermostats. When an iComfort thermostat is used with a lennox furnace, there are more advanced features of the furnace that can be used, such as turning on at partial power and better timing of the power of the furnace. Moving to a nest, you lose those advanced features of the thermostat.

I hired an HVAC specialist to activate both the normal wires and the lennox-specific wires so that I could choose which kind of thermostat to use. In the end, I chose to go with a nest for several reasons:

  1. The iComfort thermostats are something like $600 CAD and the nest is only $180 CAD
  2. I wanted to add sensors to different rooms in the house to keep track of the heat in multiple locations
  3. I trust Google's online security and safety more than I do lennox. I don't want anyone hacking into my wifi thermostat

That being said, I was on the edge of deciding to go with an iComfort because it does make better use of the furnace.

Here's a photo of my furnace's circuit board. Notice that there are two connection areas for wiring. One for the i+. i- and the other for "normal" wiring.

Oops...I don't seem to have access to upload images to this forum. You will have to use your imagination. 🙂

View Recommended Answer in original post

25 REPLIES 25

Jimmyd
Community Member

I have the same issue. Have you found a solution 

Jake
Community Specialist
Community Specialist

Hey all,

 

Sorry for the late reply. I wanted to follow up and ensure everyone is good to go. 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. 

Best regards,
Jake

I have an electric heating system with white, yellow, green and red wires for the thermostat. There are wire labels connecting the thermostat. Is my system compatible for a Nest Thermostat?

Oops. Forgot to mention the main issue. There are no labels on the wires.

Hi Mynestcommunity,

 

Thanks for the response. I'd love to know more about this. Could you share a photo of how your current thermostat is wired? Also, what is the make and model of your current thermostat?

 

Looking forward to your response.

 

Thanks,

Edward

aeisenberg
Community Member

Yes. After a lot of research, and a consultation with an HVAC expert, I was able to rewire to install the nest.

The i+, i- wires are specific to lennox furnaces and iComfort thermostats. When an iComfort thermostat is used with a lennox furnace, there are more advanced features of the furnace that can be used, such as turning on at partial power and better timing of the power of the furnace. Moving to a nest, you lose those advanced features of the thermostat.

I hired an HVAC specialist to activate both the normal wires and the lennox-specific wires so that I could choose which kind of thermostat to use. In the end, I chose to go with a nest for several reasons:

  1. The iComfort thermostats are something like $600 CAD and the nest is only $180 CAD
  2. I wanted to add sensors to different rooms in the house to keep track of the heat in multiple locations
  3. I trust Google's online security and safety more than I do lennox. I don't want anyone hacking into my wifi thermostat

That being said, I was on the edge of deciding to go with an iComfort because it does make better use of the furnace.

Here's a photo of my furnace's circuit board. Notice that there are two connection areas for wiring. One for the i+. i- and the other for "normal" wiring.

Oops...I don't seem to have access to upload images to this forum. You will have to use your imagination. 🙂

Jake
Community Specialist
Community Specialist

Hey all,

 

I want to ensure you are good to go, and everything is working properly. Please let me know if you are still having trouble, as I will be locking the thread in 24 hours due to inactivity. 

Best regards,
Jake

Do you know specifically how the HVAC unit was rewired? I have the same problem and would like to do it myself to use a Nest.

Do you have a Lennox gas furnace with an iComfort thermostat? That's all I can speak to. This is how the wiring on the furnace side was hooked up. Notice that one side uses the i+/- and the other side uses the standard wiring. It's the standard wiring that the nest uses.

https://photos.app.goo.gl/J8A7MpfBh7o56wZs9

Perfect! That's exactly what I was looking for! So, you're not using the 4 wires on the left side (i+/-) of the furnace motherboard at the Nest thermostat. just the 3 wires on the right, correct? They're just hanging disconnected?


@rhammer wrote:

Perfect! That's exactly what I was looking for! So, you're not using the 4 wires on the left side (i+/-) of the furnace motherboard at the Nest thermostat. just the 3 wires on the right, correct? They're just hanging disconnected?


That's correct. I kept them available, but disconnected on my wall upstairs just in case I ever decided to go back to using an iComfort, but I doubt I will.

Perfect. Thanks again!

Could you be more specific about the advanced features on the Google Nest Learning Thermostat that will continue to function when installed on the Lennox iComfort, and which Google features won't?

I don't know the specifics, but I think the main features that iComfort has and Nest doesn't is the ability to turn the furnace on at a lower power. For the Nest, the furnace is either on or off. The iComfort can be on, but at a lower intensity. I can't be any more specific than that. Maybe someone else knows more.

chewpr01
Community Member

When I turn on the nest it states heater. Does the nest also control AC compressor thru this 3-wire configuration?

I would think that if you want to hook up AC to the nest, you will need to include additional wires. We don't have AC, so I can't help you more than this.

chewpr01
Community Member

Simply connect Y1 to Y1 on the nest in addition to those 3-wires to the right. That gets the AC going. Nest test works and all is well.

PerryT
Community Member

"Simply" means moving the two middle wires on the left (black and white) to the Y2 and Y1 stations on the right?

 

Ryan_G
Community Specialist
Community Specialist

Hi everyone,

 

Thanks for reaching out here in the Google Nest Community.

 

I'd like to jump in here and check if you're all good to go about the concern. 

 

@PerryT, could you share a photo of your current wiring configuration? 

 

Regards,

Ryan

Jeff
Community Specialist
Community Specialist

Hi Mynestcommunity,

I just wanted to jump in real fast to see if you saw Edward's reply and to see if you still needed some help on this or if you were able to get it sorted out. If you are still needing some help, just let us know and we'll be happy to continue helping.

Thanks,
Jeff

Jeff
Community Specialist
Community Specialist

Hi everyone,

Just one quick final check in here since activity has slowed down. We'll be locking the thread in the next 24 hours, but if you still need help, I would be happy to keep it open. If there's more we can do, just let me know.

Thanks,
Jeff

Pass1277
Community Member

I can get my heater working but when I hook my y1 wire to my nest and to my panel on the unit the ac acts like it will run, in that the indoor blower motor comes on but my compressor outsidedoesn't.

 

My system doesn't have any AC, so I can't help you. You might need to get a professional to take a look.

 

esp91
Community Member

Were you ever able to figure this out? I am having the same issue.

Any update on how you solved this? Any pics of your wiring ?