Hello,

I recently had a new Trane XL16i (4ttx6048c), a Trane Variable Speed Air Handler (4tee3f49c), with 10kw electric heat, and a Trane Tcont803 thermostat installed in my house in South Florida. I am trying to confirm the wiring and thermostat settings to ensure that it is running as designed and specified.

Question 1:
The XL16i is a 2 Stage condenser unit with (1) two-step scroll compressor?

Question 2:
Based on the Tcont803 installers manual (see link below) the unit should be wired according to Fig. 8. Typical hookup of two-stage indoor and
two-step scroll cooling unit in a single transformer
system (2H/2C or 2H/1C or 1H/2C). Am I correct in this assumption?
Removed Link. Installer Guide should have been left with your system Manuals.

http://www.airconditioner-parts.com/...tallation .pdf

Wired as shown below:

T - AH - CU
Y2 - BK - Y2
W2 - W2
S1
S2
RC
R - R
W1
Y - Y - Y1
G - G
B

RC jumper to R on thermostat (factory)
R jumper to BK on air handler removed
R jumper to O on air handler


3. Which setting should be chosen in the System Type Selection in the Installer Setup Menu of the Tcont803 thermostat?

Thank you for your help. I just want the system to work as advertised considering the amount of money I paid for it.

 

Correct.

Correct.

Need to make a change. Otherwise, rest is correct.

W1 from t-stat goes to W1 on the air handler.

Do you have an extra wire in the wall for B?

Is B/C hooked up to C at the unit outside?

170-10
180-0
220-2
230-3
240-3
280-1 (makes a good night light if B is hooked up.)

If you have questions on the other settings, let me know.

 

Jay, thanks for the quick response.

I only have 5 wires from the AH to the Thermostat which are all occupied. What does W1 to W1 do? Should I run this wire?

Also there are only 2 wires coming from the outside unit. I opened it and only saw two.

Why does Trane 0170-10 say "1 heat/2 cool oil furnace or 0H/2C"? The "oil furnace" makes it confusing .

 

No problem. Glad to help.


Ok, we won't be able to hook up B (Common wire) for our back light #280 setting, so leave that at 0. I suggest to put in fresh battery once a year in the t-stat.

W1 is your heat (1st stage) and you don't have two stage (W2), so W2 needs to be moved over to W1 at both t-stat and air handler. Other wise if that was left on W2, you would not have heat if the t-stat was set up 1Heat.

What!? You need 3 wires.. Y1 to Y, Y2 to BK, and B to B/C

Not sure? I'm sure it was a misprint.

Do you want me to review the dip switch settings on the air handler for you?

 

My mistake on the original post, W1 from the Tstat goes to W1 on the AH and has a jumper to W2 on the AH.

That is correct, as it is now the T - AH - CU is as follows: Y1 - Y - Yellow/Black , and Y2 - BK - Yellow/Red. There is no third wire. I opened the condenser unit outside, and there is no wire (blue or any other color) that is not terminated, loose, or clipped. There is a blue/black wire the same gauge as the other communication wires that goes from a relay timer, through what looks like a large resistor, then into the contactor. Thoughts?

My dip switches are set as follows:

1 - ON
2- OFF
(it is a 4 ton unit)
3- OFF
4- OFF
(normal)
5- ON
6 - ON
(enhanced)
7 - ON
8 - OFF
(med-high)


Thanks Again!

 

You have the CmfortLink II System only two wire control connection. If the system is working, then I won't worry about it.

You are moving too much air, won't feel "warm" with this.. The manual calls for 700 cfm on your heat coil.

Change
8 - ON

 

Its not a ComfortLink II, i just verified the model number. I just checked again, in daylight. It does indeed have a blue wire. The installer took it to ground on the outside unit. What does the blue wire do? Should I have the installer come back and correctly wire it?

 

The "Common" wire can be grounded.

Guessing they were not able to run a new wire outside, so that's why they did it.. I've done it once before in the past where fishing a new wire was going to be very hard.

 

So this grounded blue wire will have no effect on the staging/efficiency/operation of the unit? I paid a good amount of money for the system, and I know the installer would come back out if I wasn't satisfied, so if you think I should have them connect it to the AH, I will.

Also, in the installers test mode when I cycle stage 1 and stage 2 of the compressor should there be a clear audible change?


Thanks

 

No, common wire will end up being grounded down the line.


I have not been around this unit in person, so I couldn't say for sure. You may notice it a little bit quieter, and fan running a little slower outside on 1st stage. Only best thing to tell is put an amp meter on the line, or count how long it takes for your house meter to spin around.

 

I found the wiring schematic for both the CU and AH and indeed it is grounded down the line at the AH. Just one more thing for my own sanity...If i meter the blue wire that is currently grounded (obviously disconnected from the ground), it would read +24 volts coming out?


Again Jay, thanks so much for your help.

 

No, you won't get a reading 24 volts on common wire to ground.