Aux/e port is combined using only 1 wire

[rgaila]

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Original Poster: oliver gadient 

My aux/e port is combined and uses 1 wire. I have emergency heat, and I'm fairly certain I have aux heat too.  I hooked up a nest e that I was given but one of the heating elements stayed on a when running the AC. I think I need the nest learning one, however I'm unsure how I would hook it up to avoid the same issue while maintaining both aux and emergency capabilities 

[rgaila]

Hi Oliver, 

Thanks for reaching out to us, and welcome to our community. Let's see what your wiring system means together. 

Based on your wiring setup, it looks like you have a dual-fuel system, which makes sense given you have auxillary heat (e.g., heat pump with furnace). Since these systems can have complicated wiring setups, we strongly recommend contacting a local pro to prevent any damage to your HVAC system during installation. 

Here's the guide to your wires for reference: 

• W2 controls your auxillary heat. 
• G controls your fan. 
• W controls your heating system. 
• C is your common wire, which will assist your Nest Thermostat in keeping a consistent charge in order to function. 
• Y controls your cooling system. 
• R is the power wire for both heating/cooling. Though you have an Rc terminal, it doesn't appear to be in use. If you only have one R wire (no Rh or Rc), you can connect your R wire to either Rc or Rh on the Nest thermostat.

Hope this helps! Let us know how it goes. 

-From Ai, Community Specialist.

[HobsonsChoice]

Greetings!

Did you ever figure this out? I have seemingly the same exact system and am wondering if a regular Nest will work or if I need the learning one... Any help would be appreciated! Thanks

[Jhonleanmel]

Hi HobsonsChoice,

If you have the same wiring system posted above, then you need to get the Nest Learning Thermostat which has wire terminals necessary to accommodate that type of dual-fuel system.

Best,

Mel

[Markjosephp]

Hello folks,

I wanted to stop by and see how I could help.

Thanks for helping, Mel.

@HobsonsChoice, I'd be happy to take a look into this for you. Could you please send us a picture of your thermostat's wiring diagram? Also, what's the make and model of your HVAC system?

I'll look forward to your response.

Regards,

Mark

[Markjosephp]

Hello HobsonsChoice,

I'm checking in to make sure that you've seen our response. Please let us know if you have any additional questions or concerns before we lock this thread in 24 hours.

Thanks,

Mark