Nest 3rd Gen to Trane Heat Pump TWE040E13FB2 with XR 12 condenser

[Edkuscg]

After reviewing the other posts and trying to correctly wire this I’m at a loss. Most would think its pretty straight forward but when wired up and set up as previously shown my compressor short cycles and blows cold in Cool mode. 

here is the original T-stat wiring

R jumped to Rc - Red

O - Orange

Y - Yellow

G- Green

B- Blue

X2 - Black

W1 - White

The setup i thought i needed was :

Y1 - Yellow

G- Green

OB - Orange and set up to O on thermostat

Rc - Red (although seen Rh also used since Trane likes to do things different)

W2/AUX - White

C - Blue

* - Black.

Any help on the correct set up would be greatly appreciated. Not sure if its a programming issue or a wiring issue.

Thank you in advance. 

[zoeuvre]

Hi Edkuscg, 

Uh-oh! I'm sorry to hear that you're experiencing issues with the wiring and setup of your Nest Thermostat. It's important to ensure that the thermostat is properly wired to your HVAC system to avoid any functionality problems. Here's a suggested wiring configuration based on the information you provided:

Original Thermostat Wiring:

• R (jumped to Rc) - Red
• O - Orange
• Y - Yellow
• G - Green
• B - Blue
• X2 - Black
• W1 - White

Suggested Nest Learning Thermostat Wiring:

• Rc or Rh - Red (either one should work, depending on your specific HVAC system)
• O/B - Orange (set it to O in the thermostat settings)
• Y1 - Yellow
• G - Green
• W2/AUX - White
• C - Blue
• * - Black

Gather the power readouts of your Nest Learning Thermostat's Battery, VOC, VIN, and lIN under Settings > Technical Info > Power.  Also, check your air filter, as a clogged filter might cause a similar symptom. If the air filter is dirty and needs to be changed, replace the air filter and let us know if the issue continues after they change the filter. Refer to the Air filters and filter reminders article for more details. 

Keep us posted.

Best,

Zoe

[Edkuscg]

Zoe, Thank you for the info. That’s how I’ve previously installed the thermostat but I’ve cleared everything to start fresh. Wired up the thermostat as stated above and here are the power readouts you requested.

battery : 3.835v

Voc : 33.23v

Vin : 33.23v

lin : 200mA

Set in cool mode for testing and the heat pump is blowing in hot air. Not sure why this is happening as the thermostat is set to cool and at 68 calling for cool with heat blowing.  Any other help would be appreciated. 

[Edkuscg]

Update: Heat come on in both cool and heat. 

[zoeuvre]

Hi there, 

Gotcha. Your HVAC system requires good airflow to work properly. 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 your system to shut off.

1. Find your HVAC system's air filter. The air filter is usually behind a grate in the hallway.
   • Check the air filter using your furnace's manual.
   • If you can't find the air filter, search for it inside the furnace near the fan.
2. If the air filter seems dirty, or there seems to be a clog, replace the filter. If the issue is due to frozen cooling coils, wait for the HVAC system to thaw before you use it again.

Thanks,

Zoe

[Edkuscg]

Brand new filters. The fact that the reversing valve is making heat come on with both calling for both heat and cool is telling me something isn’t right with the wiring. Any other recommendations?

[zoeuvre]

Hello Edkuscg, 

I see. Don't give up on us yet—we'd like to further check on this. Could you fill out this form and let me know once you're done?

Regards,

Zoe

[zoeuvre]

Hello there. 

Checking back in—we haven't received your form. Were you able to fill it out? Still need our help? 
 

Kind regards,

Zoe

[Edkuscg]

I did receive it. I will get it back soon 

[Edkuscg]

Filled out and sent the form in. Thank you 

[zoeuvre]

Hi there Edkuscg, 

We haven't received your form. Kindly use the same email address you use here in the Community forum to fill out the form. 

Best regards,

Zoe

[Edkuscg]

Not sure if my first message went through, it didn’t’ show up in the stream. I sent the form, thank you for following up. 

[Jenelyn_O]

Hey Edkuscg,

Chiming in — thanks for filling out the form. I received your form — I'll hand it over to our team. Please keep an eye on your inbox or messages as they will get in touch with you soon.

I appreciate your help, Zoe.

Cheers,

Jenelyn

[Edkuscg]

Thank you all for your help

[Jenelyn_O]

Hi Edkuscg,

We appreciate that — we're happy to help. If you have any questions or concerns, please feel free to create a new thread, as we'll be willing to assist you from there.

Kind regards,

Jenelyn

[Edkuscg]

Creating a new thread as the problem still exists. It might be a configuration of the thermostat issue so I’ll need some info on that. 

[Edkuscg]

Here is the link to the other post 

https://www.googlenestcommunity.com/t5/Nest-Thermostats/Nest-learning-thermostat-configuration-for-T...