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Trane Heat Pump Wiring

gummycat
Community Member

Hi,

I'm trying to ensure that my wiring is correct as I have seen conflicting information in my research. My heating seems to be working (can't testing cooling right now due to outside temp), but the conflicting information has me worried it may not be setup optimally and that that may cause problems in the long run.

Equipment

Heat Pump: Trane XL14i

Air Handler: Trane 4TEE3F49 (variable Speed with 15kw electric back-up)

(both installed in 2003)

Air Handler Wiring

IMG_4439.jpg

W2 and W3 wires are joined

R and BK seem to have a jumper on the board

Original thermostat wiring:IMG_20160831_181604.jpg

W1 and Y have a jumper despite being separate wires... very odd and has me wondering if they were supposed to fix something at the thermostat when the HVAC system was upgraded

Current Nest wiring:

IMG_4441.jpeg

My understanding of the connections with respect to Heat Pumps...

  • Y1... power out to the heat pump for heating or cooling... therefore use the yellow wire
  • OB... reversing valve depending on heating or cooling... therefore use the orange wire
  • G... fan wire blower motor... therefore use the green wire
  • Rc... power in for the Nest to send out to control heat pump... therefore use the Red Wire
  • C... common wire to power thermostat to provide constant power... therefore use the blue wire
  • Rh... power for heating when you have separate heating and cooling systems... therefore nothing is connected here
  • W1... control heating system, but not sure if this is needed with a heat pump?... I connected the white wire here because of the previous thermostat... but I wonder if the white might belong in the W2/Aux?
  • W2... control supplemental electrical heating coil on the heat pump... I connected the black wire here because of the previous thermostat... but I wonder it the black wire belongs in the *
  • *... emergency heat/accessory for heat pump failure... not currently connected to anything, but I wonder if the black wire belongs here

Questions

  • Is this equipment combination considered dual fuel system per the Nest app (it asks during installation)?
  • I believe Y1, OB, G, Rc and C connections are all correct but would love confirmation on that!
  • I'm much less confident in the W1, W2 and * connections... any corrections here?

Thanks!

1 Recommended Answer

gummycat
Community Member

Shortly after posting I found the following blog post... according to this, it looks like I should connect white wire to W2/Aux and the black wire to the * as shown below...

gummycat_0-1670099001783.png

Then I went into the system settings from the thermostat and was able to change to single fuel type. I then went into pro setup and configured the OB to change seasonally (changes when switching from heat to cool) instead of with each cycle (read somewhere that this is fewer on/off cycles which is better). After making these changes, I was then able to see Heat Pump balance settings in the temperature preferences section of the Nest iOS app for the thermostat. I tested each thing and they all seemed to work (this was true before as well). Based on this other person having what looks to be a VERY similar setup, I think their post confirms my suspicions.

Putting this here in case it helps others.

If anyone is experienced and can confirm, that would be amazing!

Thanks!

View Recommended Answer in original post

7 REPLIES 7

gummycat
Community Member

Shortly after posting I found the following blog post... according to this, it looks like I should connect white wire to W2/Aux and the black wire to the * as shown below...

gummycat_0-1670099001783.png

Then I went into the system settings from the thermostat and was able to change to single fuel type. I then went into pro setup and configured the OB to change seasonally (changes when switching from heat to cool) instead of with each cycle (read somewhere that this is fewer on/off cycles which is better). After making these changes, I was then able to see Heat Pump balance settings in the temperature preferences section of the Nest iOS app for the thermostat. I tested each thing and they all seemed to work (this was true before as well). Based on this other person having what looks to be a VERY similar setup, I think their post confirms my suspicions.

Putting this here in case it helps others.

If anyone is experienced and can confirm, that would be amazing!

Thanks!

Jake
Community Specialist
Community Specialist

Hey there,

 

I am glad you were able to get everything set up, and working properly from here. I wanted to check in with you, and see if you had any questions. Please let me know, as I would be happy to take a closer look.

 

Best regards,

Jake

gummycat
Community Member

Jake,

 

Thanks for checking in.  I'm pretty sure it is setup correctly with the mentioned adjustments, but if you have experience that confirms where I landed, that'd be awesome!

 

Thanks!

Michael

Jake
Community Specialist
Community Specialist

Hey there,

 

Sorry for the delayed reply. Taking a closer look at the wiring, and the diagram you have posted, I am showing that everything looks to be set up properly. I also found this article that has some details about Aux heat. Here is an article with more details on emergency heat that you can read through for more details. Let me know if you have any questions from here, as I would be happy to review.

 

Best regards,

Jake

Markjosephp
Community Specialist
Community Specialist

Hi folks,

 

Thanks for assisting, Jake.

 

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

Best,

Mark

No further help needed… thanks!

Markjosephp
Community Specialist
Community Specialist

Hi gummycat,

 

Sounds good! Thanks for letting us know. We can probably consider this one finished, so I'll close the thread in 24 hours unless I can help with anything else. 

 

Regards,

Mark