Wiring Trane XL624 Thermostat


Old 07-04-16, 02:53 PM
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Join Date: Jul 2016
Location: USA
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Wiring Trane XL624 Thermostat

I have a Trane heat pump that was installed in 2006 (Model # 4TEE3F31A1000AB) with a Trane programmable thermostat. I recently purchased a Z-Wave enabled Trane XL624 thermostat so I could integrate the HVAC system into my home automation system. I expected the wiring to be straight forward since I was replacing one Trane thermostat with another, but this was not the case. The wiring connections for the two thermostats have different letter codes so I'm not certain which wire goes to which connection on the new thermostat. I've included three pictures I hope will help:

Picture 1 - Connections at system
Black and White wires are connected to W1
Yellow Wire to Y
Blue wire to B
Orange Wire to O
Red wire to B (R?) and appears to be jumped with BK
Green wire to G
Name:  Existing System Wiring.jpg
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Picture 2 - Connections to existing thermostat
Black wire to X2
White wire to W1
Red wire to R and appears to be jumped with RC
Orange wire to O
Green wire to G
Blue wire to B
Name:  Existing Thermostat Wiring.jpg
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Picture 3 - Connections on new Thermostat
Name:  New Thermostat.jpg
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Any and all help will be much appreciated.

Best regards,

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Old 07-05-16, 07:15 AM
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Red -R
White - W1
Black - W2
Orange - O/B
Blue - C
Yellow - Y2
Green - G

Configure for heat pump with Aux heat.
Old 07-10-16, 07:17 AM
Thread Starter
Join Date: Jul 2016
Location: USA
Posts: 2
Got it working - THANK YOU!
Old 01-16-17, 12:06 PM
Join Date: Jan 2017
Location: USA
Posts: 2
Another XL624 question...

I have a Trane Heat Pump (model 4TWR5042E1000AB) and a Trane GAM5A Air Handler. My old thermostat was a model TCONT401AN21MAA and I just installed an XL624

The thermostat installation manual shows that with a heat pump, there is a W2 wire in addition to the W1 wire and that's the only difference. But I didn't have any W2 wire connected to my old thermostat, so I'm confused. I do have a brown and a black that were unused in the old Tstat. This is what I have, which is exactly the way the old Tstat was wired:

Red to R
Blue to B/Common
White to W1
Orange to O
Green to G
Yellow to Y1

Problem is, when the air is supposed to come on, the heat does. I've attached pictures of the old Tstat wiring, the wiring guide on the outside of the air handler, the air handler wiring block and XL624 block. Any help would be GREATLY appreciated. TIA
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Old 01-17-17, 06:33 PM
Join Date: Jan 2017
Location: USA
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Couldn't see any way to delete my post but the problem has been resolved. It was wired properly but the settings in the Tstat needed to be adjusted for my setup.
Old 01-17-17, 06:54 PM
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Welcome to the forums.

Glad you got your problem resolved.
Don't worry about the thread. It will travel on thru the system.
Old 03-03-17, 07:52 PM
Join Date: Mar 2017
Location: USA
Posts: 6
Trane XL624 Backlight Will Not Dim

I have installed an XL624 thermostat on my 4TWX/4TEE system. Everything seems to work except I cannot get the backlight to dim. Screen timeout works; after the delay time the thermostat goes to showing the temperature in large font. I have set the backlight timeout to 5 seconds and the backlight off percentage to 20% but the backlight stays on full time. Am I missing something?


Old 03-04-17, 11:33 AM
Join Date: Mar 2017
Location: USA
Posts: 6
Wiring Diagrams for my Installation

Here is how my system is wired with the XL624 based on helpful information I found on here and data from my system's installation instructions, followed by how it was originally wired with the TCONT802. It seems to work normally on cool. I have not checked it on heat.

Is it wired correctly? I have not connected the condensate switch shown in the red wire of the TCONT802 diagram yet. How should it be wired?

Is there anything in the wiring that would affect the backlight?


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