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Trane 2 stage heating/cooling with Nest Learning thermostat

seansanders82
Community Member

Hello, I have a Trane XV90 with a Trane XL19i heat pump. The system has two stage heating and two stage cooling. I wired up my nest learning thermostat and can only get the two stage cooling to run, and no heating. I have included pictures of the original wiring as well as the current wiring with the nest thermostat. Any advice or help is appreciated. Thank you

A1CDF59C-0767-46C1-9D81-6A6B4F7E7FF6.jpeg

2384FD12-353D-4DF5-8EAF-28AFF333FC90.jpeg

1 Recommended Answer

Houptee
Silver Product Expert
Silver Product Expert

Remove White wire from OB and move it to the W1 on the Nest.

W1 is 1st stage heat and probably why you are not getting the full heat output.


Houptee -- NJ Master HVAC Licensed Contractor

View Recommended Answer in original post

15 REPLIES 15

Houptee
Silver Product Expert
Silver Product Expert

On your old Tstat it says the outer labels are for Heat Pumps, so if you match it up to the other labels you wired the Nest wrong.

Orange went to Y2 and Black was W1 and Yellow was O

If the heat pump does not run in heat mode you can alter what O/B wire does in the Nest settings. Some systems need voltage output on O/B some need the opposite to switch the heat pump to heat mode.


Houptee -- NJ Master HVAC Licensed Contractor

Patrick_Caezza
Platinum Product Expert
Platinum Product Expert

The wire colors mean nothing as there is no standard. Follow the terminal block labels on the outside of the original thermostat.

Try this wiring.

Orange - Y2 to Y2

Black - W1 to W2 (set as AUX heat)

Red - R to Rc (jumper to RC not needed)

White - O to OB

Yellow - Y to Y1

Green - G to G

Blue - B to C

Do a reset to factory defaults when you change the wiring.


To ensure that I see your reply, please tag me using @Patrick_Caezza

I adjusted the wiring per your directions and got the following results.I adjusted the wiring per your directions and got the following results:

  • Stage one heating = hot / low speed
  • Stage two heating = cold / high speed
  • Stage one cooling = cold / low speed 
  • Stage two cooling = cold / high speed

I’m at least getting some heat now, but not sure why it won’t run on high speed.

Any ideas?

 

 

 

 

seansanders82
Community Member

Current wiring on nest

F95DECC4-8586-450F-9A9D-8E97C6195EFD.jpeg

 

Current wiring on Trane XV90

B856253E-AC91-4A97-BEDF-D22648B76137.jpeg

Patrick_Caezza
Platinum Product Expert
Platinum Product Expert

Are you positive that you have a Trane XL19i heat pump? Heat pumps require an Air Handler and not a furnace.

You say you have an XL90 Furnace, and it is not designed to work with a Heat Pump.

Even the wiring in your furnace doesn't match up with the wiring for a heat pump.

 


To ensure that I see your reply, please tag me using @Patrick_Caezza

Maybe I don’t have my nomenclature correct. I have an XV90 inside my house and a big unit outside that says XL19i on it. I assumed it was a heat pump but sounds like I’m wrong. Does that change the wiring configuration? Thanks again

EdwardT
Community Specialist
Community Specialist

Hi folks,

 

@Patrick_Caezza and Houptee, We always appreciate the help!

 

@seansanders82, how's it going with your Nest Thermostat? Still need our help?

 

Thanks,

Edward

I think I’ve got it figured out now, thank you 

Houptee
Silver Product Expert
Silver Product Expert

Remove White wire from OB and move it to the W1 on the Nest.

W1 is 1st stage heat and probably why you are not getting the full heat output.


Houptee -- NJ Master HVAC Licensed Contractor

This seemed to do the trick, thank you

EdwardT
Community Specialist
Community Specialist

Hi seansanders82,

 

I'm glad to hear that you were able to get it working. Please observe it for now and let us know if anything comes up.

 

Thanks,

Edward

EdwardT
Community Specialist
Community Specialist

Hi seansanders82,

 

I wanted to follow up and see if you are still in need of any help. 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.

 

Thanks,

Edward

Seems to be working as expected. Thanks again for checking in.

Sean

EdwardT
Community Specialist
Community Specialist

Hi seansanders82, 

 

Thanks for the update. I'm glad to hear that it's working fine. Please let us know if you have any other questions or concerns as I will be locking this in 24 hours.

 

Thanks,

Edward