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Nest Wiring

Admf8
Community Member

E8B351CC-D3D5-4019-BD1A-AF53BAF3B4DA.jpegwill nest gen 3 work with this wiring. The unit is a heat pump with aux heat. Thanks

1 Recommended Answer

EdwardT
Community Specialist
Community Specialist

Hi Admf8,

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

Thanks,

Edward

View Recommended Answer in original post

14 REPLIES 14

Markjosephp
Community Specialist
Community Specialist

Hello Admf8,

Thank you for taking the time to let us know about your inquiry. I'd love to help.

It would be compatible with Nest Thermostats based on its configurations. Here's a wiring diagram for you to follow:

Please let me know if that helps.

Best regards,

Mark

Hey there,

I wanted to see if you still needed help. Please let us know if you have any other questions or concerns.

Thanks,

Mark

Admf8
Community Member

Hi Mark

i set up the nest as you had shown and now I am getting an E73 error. I had previously had this nest installed but the aux heat did not work, but everything else did

Markjosephp
Community Specialist
Community Specialist

Hi there,

Thanks for responding back to us — let's sort this out.

It appears that your system may not provide enough power or any power to either the thermostat or a specific wire (so the thermostat can’t complete a circuit and shows the E73 code). To isolate:

  • Make sure that their breakers are on.
  • Gather the power readouts from the technical info settings under power.
  • Make sure the thermostat wires are properly stripped and seated in the thermostat base.
  • Move the Rc wire to the Rh terminal.
  • Check the air filter.
    • A clog in the air filter can limit how much air flows over the cooling coils. If the clog persists, the cooling coils can freeze and cause the system to shut off.
  • Check the emergency switch and drip pan.
    • Ensure that it's on and not clogged.
  • Check the condition of your HVAC fuse. Occasionally, fuses burn out due to one or more reasons.
    • If the HVAC fuse burns out, the system may cut off the power to the thermostat and cause an E73/E74 power message.

Please note: turn off the power from the HVAC system at the breaker box before touching the wires.

Keep me posted on how it goes.

Best,

Mark

Hello Admf8

I'm checking back in. Were you able to do the steps above? I'd be glad to hear from you — I'd like to make sure everything is working.

Thanks,

Mark

Hi Mark

I installed this Nest stat several months ago and didn’t A004644F-E36B-4E98-85B9-85F30673C2BB.jpeg

have any concerns until the temps dropped. This is when I found that the aux heat was not working. With the wiring shown in the pic has worked well for heat pump heat and cooling, just not when there’s a need for the aux heat. Thanks for your continued support.

EdwardT
Community Specialist
Community Specialist

Hi Admf8,

Thanks for the response and sharing a photo of your Nest Thermostat. It appears that your AUX wire is connected to the C terminal. Could you try connecting it to the W2 terminal? Please make sure that you turn off the breakers before touching the wires.

Thanks,

Edward

Admf8
Community Member

Hi Edward

Moving the common wire to W2 was an original suggestion from Mark. Doing this resulted in an E73 error code.

EdwardT
Community Specialist
Community Specialist

Hi Admf8,

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 Admf8,

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

Thanks,

Edward

Admf8
Community Member

Hi Edward

yes I did complete the form and would appreciate further assistance.

 

 Thanks 

EdwardT
Community Specialist
Community Specialist

Hi Admf8,

 

Thanks for the response. We can't seem to find your form. Could you fill it out again and include the link to this thread?

 

Thanks,

Edward

Admf8
Community Member

Hi Edward

i re-submitted the form

EdwardT
Community Specialist
Community Specialist

Hi Admf8,

 

We got your form — thanks for filling it out. Our team will reach out to you via email to further assist you. Also, please be advised that this thread will be locked after 24 hours.

 

Thanks,

Edward